@article {ma13030745, title = {Experimental Evaluation of Mode II fracture Properties of Eucalyptus globulus L.}, journal = {Materials}, volume = {13}, number = {3}, year = {2020}, note = {n/a}, abstract = {

Eucalyptus globulus Labill is a hardwood species of broad growth in temperate climates, which is receiving increasing interest for structural applications due to its high mechanical properties. Knowing the fracture behaviour is crucial to predict, through finite element models, the load carrying capacity of engineering designs with possibility of brittle failures such as elements with holes, notches, or certain types of joints. This behaviour can be adequately modelled on a macroscopic scale by the constitutive cohesive law. A direct identification of the cohesive law of Eucalyptus globulus L. in Mode II was performed by combining end-notched flexure (ENF) tests with digital image correlation (DIC) for radial-longitudinal crack propagation system. The critical strain energy release for this fracture mode, which represents the material toughness to crack-growth, was determined by applying the Compliance Based Beam Method (CBBM) as data reduction scheme and resulted in a mean value of 1.54 N/mm.

}, issn = {1996-1944}, doi = {10.3390/ma13030745}, url = {https://www.mdpi.com/1996-1944/13/3/745}, author = {Majano-Majano, Almudena and Lara-Bocanegra, Antonio Jos{\'e} and Jos{\'e} Xavier and Morais, Jos{\'e}} } @article {CATALANOTTI2020112068, title = {High strain rate characterisation of intralaminar fracture toughness of GFRPs for longitudinal tension and compression failure}, journal = {Composite Structures}, volume = {240}, year = {2020}, note = {n/a}, pages = {112068}, abstract = {

The elastic parameters, strengths, and intralaminar fracture toughness are determined for an E-Glass polymer composite material system, statically and at high strain rate, adapting methodologies previously developed by the authors for different carbon composites. Dynamic experiments are conducted using tension and compression Split-Hopkinson Bars (SHBs). A unique set of experimental parameters is obtained, and reported together with the experimental set-up, in order to ensure reproducibility. While in-plane elastic and strength properties were obtained by testing one specimen geometry, intralaminar fracture properties required the testing of different sized notched specimens with scaled geometries. This allowed the use of the size-effect method for the determination of the dynamic R-curve. When comparing these results with those previously obtained for a carbon/epoxy material system, it is observed that the dynamic fracture toughness exhibits a much more significant increase in both tension and compression. The obtained results permit the identification of the softening law at different strain rates, allowing its use in any analytical or numerical strength predictive method.

}, keywords = {Dynamic characterisation, Glass fibre reinforced plastics (GFRPs), Intralaminar R-curve, Size-effect}, issn = {0263-8223}, doi = {https://doi.org/10.1016/j.compstruct.2020.112068}, url = {http://www.sciencedirect.com/science/article/pii/S0263822319343958}, author = {G. Catalanotti and P. Kuhn and J. Xavier and H. Koerber} } @article {PEREIRA2020105482, title = {Low and ultra-low-cycle fatigue behavior of X52 piping steel based on theory of critical distances}, journal = {International Journal of Fatigue}, year = {2020}, note = {n/a}, pages = {105482}, abstract = {

The cyclic failure observed in structural components such as pipelines subjected to extreme loading conditions highlights some limitations concerning the application of existing fatigue damage models. The evaluation and prediction of this type of failure in these steel components under large-scale plastic yielding associated with high levels of stress triaxiality are not sufficiently known nor explored. This fatigue domain is conventionally called ultra-low-cycle fatigue (ULCF) and damage features are representative of both low-cycle fatigue (LCF) and monotonic ductile fracture. Thus, in order to understand the ULCF damage mechanisms both monotonic and LCF tests are required to get representative bounding damage information to model the material damage behaviour under such extreme loading conditions. This paper aims at exploring the Theory of Critical Distances (TCD) in the LCF and ULCF fatigue regimes, including the application of the point, line and area methods. The application of the TCD theories has not been explored so far in the ULCF fatigue regimes, despite its promising results in the LCF and high-cycle fatigue. An experimental program was carried out on several specimens{\textquoteright} geometries made of X52 piping steel. In detail, smooth plane specimens and notched plane specimens were cyclic loaded under tension/compression loading in order to obtain fatigue lives within the range of 101-104 cycles. In addition, cyclic bending tests on notched plane specimens were also incorporated in this study. Finite element simulations of all small-scale tests were conducted allowing to derive elastoplastic stress/strain fields along the potential crack paths. The numerical data were subjected to a post-processing in order to find characteristic lengths that can be treated as a fatigue property according to the TCD. A unified strain-life relation is proposed for the X52 piping steel together with a characteristic material length, consisting of a practical relation for pipeline strain-based design under extreme cyclic loading conditions.

}, keywords = {cyclic plasticity, LCF, piping steel, Theory of Critical Distances, ULCF}, issn = {0142-1123}, doi = {https://doi.org/10.1016/j.ijfatigue.2020.105482}, url = {http://www.sciencedirect.com/science/article/pii/S014211232030013X}, author = {J.C.R. Pereira and A.M.P. de Jesus and J. Xavier and J.A.F.O. Correia and L. Susmel and A.A. Fernandes} } @article {CIDADE2019707, title = {Determination of mode I dynamic fracture toughness of IM7-8552 composites by digital image correlation and machine learning}, journal = {Composite Structures}, volume = {210}, year = {2019}, note = {n/a}, pages = {707 - 714}, abstract = {

An optical experimental procedure for evaluating the J-Integral from full-field displacement fields under dynamic loading is proposed in this work. The methodology is applied to measure the J-integral in the dynamic compressive loading of fiber-reinforced composites and to calculate the dynamic fracture toughness associated with the propagation of a kink-band. A modified J-Integral that considers inertia effects is calculated over the full-field measurements obtained by digital image correlation, for double edge-notched specimen of IM7-8552 laminates dynamically loaded in a split-Hopkinson pressure bar (SHPB). A sensibility study is conducted to address the influence of the speckle parameters. The results show good agreement with experimental observations obtained by using a different data reduction method, suggesting the existence of a rising R-curve for the studied material under dynamic loading. Furthermore, it was noticed that the inertia effect can be negligible, indicating a state of dynamic equilibrium in which quasi-static approaches may comfortably be used.

}, keywords = {Digital image correlation (DIC), Dynamic fracture toughness, Fiber-reinforced composite materials, J-Integral}, issn = {0263-8223}, doi = {https://doi.org/10.1016/j.compstruct.2018.11.089}, url = {http://www.sciencedirect.com/science/article/pii/S0263822318320932}, author = {Rafael A. Cidade and Daniel S.V. Castro and Enrique M. Castrodeza and Peter Kuhn and Giuseppe Catalanotti and Jose Xavier and Pedro P. Camanho} } @article {doi:10.1177/1464420718799116, title = {Fracture characterization of a cast aluminum alloy aiming machining simulation}, journal = {Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications}, volume = {233}, number = {3}, year = {2019}, note = {n/a}, pages = {402-412}, abstract = {

Despite extensive research regarding metal cutting simulation, the current industrial practice very often relies on empirical data when it comes to tool design. In order accurately simulate the cutting process it is not only important to have robust numerical models that closely portray the phenomenon, but also to properly characterize the material taking into account the cutting conditions. The goal of this investigation focuses on the mechanical characterization of the cast aluminum alloy AlSi9Cu3 by conducting both compression and fracture tests. Due to its very good castability, machinability, and attractive mechanical properties, this alloy is widely used in casting industry for the manufacture of automotive components, among others. Besides the experimental characterization, a numerical methodology is proposed for the modeling of the cast alloy, making use of the Johnson{\textendash}Cook constitutive material model, in Abaqus/CAE. The material model is calibrated based on compression tests at multiple conditions (quasi-static, incremental dynamic and high temperatures). The identified model is then validated by simulation of the ductile fracture tests of notched specimens. The obtained numerical results were consistent with the experimentally obtained, contributing to the validity of the presented characterization technique.

}, doi = {10.1177/1464420718799116}, url = {https://doi.org/10.1177/1464420718799116}, author = {TEF Silva and S Gain and D Pinto and A.M.P. de Jesus and J. Xavier and Reis, A. and P. A. R. Rosa} } @article {GOMES2019900, title = {High strain rate compressive behaviour of wood on the transverse plane}, journal = {Procedia Structural Integrity}, volume = {17}, year = {2019}, note = {

3rd International Conference on Structural Integrity, ICSI 2019, 2-5 September 2019, Funchal, Madeira, Portugal

}, pages = {900 - 905}, abstract = {

The high strain rate compressive behaviour of Pinus pinaster Ait. wood along the radial and tangential material axes was addressed in this work. Both quasi-static and dynamic tests were considered for comparation purposes. The quasi-static compression tests were performed on rectangular prismatic specimens along the radial and tangential directions coupled with digital image correlation. The high strain rate tests were carried out using a classical split-Hopkinson pressure bar coupled with a high-speed imaging system allowing independent kinematic measurements through digital image correlation. From these tests and material symmetry orientations, the constitutive curves were determined from which the Young modulus, Poisson{\textquoteright}s ratio and yield stress were evaluated and compared over the two different regimes over the strain rate spectrum. The mechanical properties observed for this species under quasi-static compression loading agree with reference values. A qualitative comparison between quasi-static and high strain rate regimes reveals a significant increase of some mechanical properties by increasing the strain rate. Quantitatively, by comparing mean values at the two strain rates, it was found that, in the radial direction, the modulus of elasticity increased by 6.3\%, the yield stress showed an increase of 130.3\% and the Poisson{\textquoteright}s ratio is slightly higher by 3.0\%. Furthermore, in the tangential direction, it was found that the modulus of elasticity increased by 21.9\% while the value of the yield stress showed an increase of 111.8\%, and finally the Poisson{\textquoteleft}s ratio presented a reduction of 24.3\%.

}, keywords = {high strain rate, Wood}, issn = {2452-3216}, doi = {https://doi.org/10.1016/j.prostr.2019.08.120}, url = {http://www.sciencedirect.com/science/article/pii/S2452321619303294}, author = {F Gomes and J. Xavier and H. Koerber} } @article {ma12010023, title = {Measuring the Cohesive Law in Mode I Loading of Eucalyptus globulus}, journal = {Materials}, volume = {12}, number = {1}, year = {2019}, note = {n/a}, abstract = {

Assessing wood fracture behavior is essential in the design of structural timber elements and connections. This is particularly the case for connections with the possibility of brittle splitting failure. The numerical cohesive zone models that are used to simulate the fracture behavior of wood make it necessary to assume a cohesive law of the material that relates cohesive tractions and crack opening displacements ahead of the crack tip. This work addresses the determination of the fracture cohesive laws of Eucalyptus globulus, a hardwood species with great potential in timber engineering. This study centres on Mode I fracture loading for RL and TL crack propagation systems using Double Cantilever Beam tests. The Compliance-Based Beam Method is applied as the data reduction scheme in order to obtain the strain energy release rate from the load-displacement curves. The cohesive laws are determined by differentiating the relationship between strain energy release rate and crack tip opening displacement. The latter is measured by the digital image correlation technique. High strain energy release rates were obtained for this species, with no big differences between crack propagation systems. The difference between the crack systems is somewhat more pronounced in terms of maximum stress that determines the respective cohesive laws.

}, issn = {1996-1944}, doi = {10.3390/ma12010023}, url = {https://www.mdpi.com/1996-1944/12/1/23}, author = {Majano-Majano, Almudena and Lara-Bocanegra, Antonio Jos{\'e} and Jos{\'e} Xavier and Morais, Jos{\'e}} } @article {Raposo2018396, title = {Characterization of the mechanical behaviour of wooden construction materials from quinta lobeira de cima}, journal = {International Journal of Structural Integrity}, volume = {9}, number = {3}, year = {2018}, note = {

n/a

}, pages = {396-410}, abstract = {

Purpose The antique structures are part of the inheritance that our elders left, being important to preserve their memories. It is important to preserve, rehabilitate and restore the historic buildings protecting the cultural patrimony, attending to the actual comfort and habitability requirements. It is necessary to study the behaviour of the various elements that compose antique structures (masonry and wood) in order to develop assessment measures according to the characteristics of the original materials. The paper aims to discuss these issues. Design/methodology/approach An experimental campaign to characterize the mechanical behaviour of the wood of the roof of the �sequeiro� of �Quinta Lobeira de Cima�, a building from the twentieth century located in Minho, was carried out. The tested wood specimens are from two different species: chestnut and oak. Compression, tension and static flexion tests according to parallel to the grain direction were performed. Other parameters, such as density, moisture content and longitudinal modulus of elasticity in compression and in tension, were also obtained. The measurement of displacements was made with Digital Image Correlation (DIC). Findings The results of this study show the similarity between experimental and empirical values for the studied woods species. Originality/value This original study aimed at characterizing the mechanical properties using DIC of wood of the roof of the �sequeiro� of �Quinta Lobeira de Cima�, a building from the twentieth century located in Minho (Portugal). This study is part of master thesis of Jo�o Martins, an original research work.

}, doi = {10.1108/IJSI-06-2017-0039}, url = {https://doi.org/10.1108/IJSI-06-2017-0039}, author = {P. Raposo and J. Martins and J. Correia and Maria E. Salavessa and Cristina Reis and Jos{\'e} Xavier and Abilio M.P. de Jesus} } @article {Fernandes201819, title = {Durability of bond in NSM CFRP-concrete systems under different environmental conditions}, journal = {Composites Part B: Engineering}, volume = {138}, year = {2018}, note = {

n/a

}, pages = {19 - 34}, abstract = {

Abstract This paper addresses the durability of bond between concrete and carbon fibre reinforced polymer (CFRP) strips installed according to the near-surface mounted (NSM) technique (NSM CFRP-concrete systems) under the effects of two main groups of environmental conditions: (i) laboratory-based ageing conditions; (ii) real outdoor ageing conditions. The bond degradation was evaluated by carrying out direct pullout tests on aged specimens that were previously subjected to distinct environmental conditions for different periods of exposure. Moreover, the degradation of the mechanical properties of the involved materials was investigated. The digital image correlation (DIC) method was used to document the evolution of the deformation fields at the surface over the whole region of interest consisting of concrete and epoxy adhesive at the ligament region. This information supported the discussion about the evolution of the bond resistant mechanism developed in \{NSM\} CFRP-concrete specimens during testing, as well as the assessment of the bond quality of the system. In general, the results obtained from the durability tests conducted have shown that the different exposure environments, which may be considered as quite severe, did not result in significant damage on \{NSM\} CFRP-concrete system. The maximum decrease of about 12\% on bond strength was obtained for real outdoor environments. Conversely, a maximum increase of 8\% on bond strength was obtained on the specimens exposed to the temperature cycles between -15��C and +60��C. \{DIC\} allowed to document the stress transfer mechanisms established between the \{CFRP\} and the concrete substrate, revealing the crack patterns and the influence widths of the \{CFRP\} reinforcement strips, which were shown to be important for avoiding group effect when using multiple parallel strengthening \{CFRP\} strips.

}, keywords = {Carbon fibre, Debonding, Environmental degradation, Mechanical testing, Near-surface mounted systems}, doi = {https://doi.org/10.1016/j.compositesb.2017.11.022}, url = {https://www.sciencedirect.com/science/article/pii/S1359836817311332}, author = {Pedro Fernandes and Jos{\'e} Sena-Cruz and Jos{\'e} Xavier and Patr{\'\i}cia Silva and Eduardo Pereira and Jos{\'e} Cruz} } @article {Kuhn201802018, title = {Intralaminar fracture toughness of UD glass fiber composite under high rate fiber tension and fiber compression loading}, journal = {EPJ Web Conferences}, volume = {183}, year = {2018}, note = {

n/a

}, pages = {02018}, abstract = {

n/a

}, doi = {10.1051/epjconf/201818302018}, url = {https://doi.org/10.1051/epjconf/201818302018}, author = {P. Kuhn and H. Koerber and G. Catalanotti and J. Xavier} } @article {doi:10.1177/0309324718791087, title = {Measuring orthotropic bending stiffness components of Pinus pinaster by the virtual fields method}, journal = {The Journal of Strain Analysis for Engineering Design}, volume = {53}, number = {8}, year = {2018}, note = {

n/a

}, pages = {556-565}, abstract = {

Orthotropic stiffness components of Pinus pinaster Ait. wood are simultaneously determined by means of a heterogeneous plate bending test. The proposed inverse identification approach couples full-field slope measurements provided by deflectometry with the virtual fields methods. Wooden plates oriented in the longitudinal{\textendash}radial and longitudinal{\textendash}tangential material planes were manufactured. A procedure was implemented to allow suitable specular reflective coating of the wooden plates, required in the deflectometry technique. Reconstructed curvature fields, applied load and plate dimensions were input in virtual fields methods for material parameter identification, assuming Kirchhoff{\textendash}Love classical plate theory. Several virtual fields and load cases were analysed to address the identifiability of the method. The values of the orthotropic elastic constants obtained from the proposed approach were found in good agreement with regard to reference ones for the same species and determined from classical tensile, compression and shear mechanical tests.

}, doi = {10.1177/0309324718791087}, url = {https://doi.org/10.1177/0309324718791087}, author = {J. Xavier and F. Pierron} } @article {Pereira2018448, title = {Determination of mode II cohesive law of bovine cortical bone using direct and inverse methods}, journal = {International Journal of Mechanical Sciences}, volume = {138-139}, year = {2018}, note = {n/a}, pages = {448 - 456}, abstract = {

This study presents two alternative methods to determine the cohesive law of bovine cortical bone under mode II loading, employing the End Notched Flexure (ENF) test. The direct method results from the combination of the progress of the mode II strain energy release rate with the crack tip shear displacement, obtained by digital image correlation. The resulting cohesive law is determined by differentiation of this relation relatively to the crack shear displacement. The inverse method employs finite element analyses with cohesive zone modelling, in association with an optimization procedure. The resulting strategy enables determining the cohesive law without establishing a pre-defined shape. The significant conclusion that comes out of this work is that both methods offer consistent results regarding the estimation of the cohesive law in bone. Given that the inverse method dispenses the use of sophisticated equipment to obtain the cohesive law in bone, it can be used as a more convenient procedure to accomplish efficient studies in the context of bone fracture characterization under mode II loading.

}, keywords = {Bovine cortical bone, Cohesive law, End notched flexure, Mode II}, issn = {0020-7403}, doi = {https://doi.org/10.1016/j.ijmecsci.2018.02.009}, url = {http://www.sciencedirect.com/science/article/pii/S0020740317327479}, author = {F.A.M. Pereira and de M.F.S.F. Moura and N. Dourado and J.J.L. Morais and J. Xavier and M.I.R. Dias} } @article {Kuhn2018276, title = {Determination of the crack resistance curve for intralaminar fiber tensile failure mode in polymer composites under high rate loading}, journal = {Composite Structures}, volume = {204}, year = {2018}, note = {n/a}, pages = {276-287}, abstract = {

This paper presents the determination of the crack resistance curve of the unidirectional carbon-epoxy composite material IM7-8552 for intralaminar fiber tensile failure under dynamic loading. The methodology, proposed by Catalanotti et al. (2014) for quasi-static loading conditions, was enhanced to high rate loading in the order of about 60 ?s-1. Dynamic tests were performed using a split-Hopkinson tension bar, while quasi-static reference tests were conducted on a standard electromechanical testing machine. Double-edge notched tension specimens of different sizes were tested to obtain the size effect law, which in combination with the concepts of the energy release rate is used to measure the entire crack resistance curve for the fiber tensile failure mode. Digital image correlation is applied to further verify the validity of the experiments performed at both static and dynamic loading. The data reduction methodology applied in this paper is suitable for intralaminar fiber failure modes without significant delamination. Sufficient proof is given that quasi-static fracture mechanics theory can also be used for the data reduction of the dynamic tests. It is shown, that the intralaminar fracture toughness for fiber tensile failure of UD IM7-8552 increases with increasing rate of loading.

}, keywords = {Dynamic fracture, Fiber-reinforced composites, R-curve, Size effect}, doi = {https://doi.org/10.1016/j.compstruct.2018.07.039}, url = {http://www.sciencedirect.com/science/article/pii/S0263822318308079}, author = {P. Kuhn and G. Catalanotti and J. Xavier and M. Ploeckl and H. Koerber} } @article {Crespo2018, title = {Determination of the resistance-curve in Eucalyptus globulus through double cantilever beam tests}, journal = {Materials and Structures}, volume = {51}, number = {3}, year = {2018}, note = {n/a}, pages = {77}, abstract = {

The prediction of the fracture behaviour through reliable and practical criteria in the design of structural timber elements and connections has become of great importance and demands a proper fracture characterization of the material. Eucalyptus globulus Labill is envisioned as a hardwood species with great potential for high performance structural purposes because of its major mechanical and durability properties, being so far mainly used in paper industry. Experimental research on the identification of the resistance curves to derive the critical strain energy release rate in Eucalyptus globulus L. under pure mode I and RL crack propagation system is performed by means of Double Cantilever Beam tests. Three different data reduction schemes are compared: the Modified Experimental Compliance Method; and two approaches of the Compliance Based Beam Method. These methods take into account the non negligible damage mechanisms at the fracture process zone and have the advantage of being based exclusively on the specimen compliance following an equivalent crack concept, for which crack length monitoring during testing is not required. The Compliance Based Beam Method turns out to be the most appropriate data reduction scheme to obtain the critical energy release rate in eucalyptus because of its simplicity. Concerning this, a high average value of 720�J/m2 was obtained confirming Eucalyptus globulus L. as a promising hardwood species for timber structural design.

}, issn = {1871-6873}, doi = {10.1617/s11527-018-1209-9}, url = {https://doi.org/10.1617/s11527-018-1209-9}, author = {J. Crespo and A. Majano-Majano and J. Xavier and M. Guaita} } @article {Pereiraetal2018, title = {Identification of transverse elastic properties of the diaphysis of cortical bone}, journal = {Journal of Mechanical Engineering and Biomechanics}, volume = {2}, number = {5}, year = {2018}, note = {n/a}, pages = {50-55}, abstract = {n/a}, doi = {10.24243/JMEB/2.5.172}, url = {https://doi.org/10.24243/JMEB/2.5.172}, author = {B. Pereira and J. Xavier and Pereira, F. and Morais, J} } @article {Xavier2018462, title = {Non-linear shear behaviour of bovine cortical bone by coupling the Arcan test with digital image correlation}, journal = {Optics and Lasers in Engineering}, volume = {110}, year = {2018}, note = {n/a}, pages = {462-470}, abstract = {

The non-linear shear behaviour of bovine cortical bone is measured by coupling the Arcan test with digital image correlation. The experimental study is carried out on specimens taken from bovine femur and oriented along the longitudinal-tangential material plane. An ad hoc Arcan fixture is built to transfer the cross-head displacement of the testing machine into a shear loading at the centre of the V-notched section. A validation of predominant shear behaviour at the gauge section is shown from full-field deformation measurements. Moreover, direct evaluation of the shear modulus is obtained by integrating the shear strain component along the V-notches, avoiding numerical correction factors required in the classical data reduction scheme. The shear modulus of bovine cortical bone is found in good agreement with references from literature. Moreover, the shear stress at maximum load is understood as a suitable estimation of the shear strength. Furthermore, the Ramberg�Osgood model is found to provide an accurate description of the non-linear shear behaviour of bone tissue.

}, keywords = {Arcan shear test, Cortical bone, Digital Image Correlation, Finite element method, Non-linear shear behaviour}, doi = {https://doi.org/10.1016/j.optlaseng.2018.07.004}, url = {http://www.sciencedirect.com/science/article/pii/S0143816618302288}, author = {J. Xavier and Morais, J and Pereira, F.} } @article {doi:10.1177/0309324718786351, title = {On the identification of earlywood and latewood radial elastic modulus of Pinus pinaster by digital image correlation: A parametric analysis}, journal = {The Journal of Strain Analysis for Engineering Design}, volume = {53}, number = {8}, year = {2018}, note = {n/a}, pages = {566-574}, abstract = {

This work addresses the reconstruction of strain gradient fields at the wood growth ring scale from full-field deformation measurements provided by digital image correlation. Moreover, the spatial distribution of the earlywood and latewood radial modulus of elasticity is assessed. Meso-scale tensile tests are carried out on Pinus pinaster Ait. wooden specimens oriented in the radial{\textendash}tangential plane under quasi-static loading conditions. A parametric analysis of the two-dimensional digital image correlation extrinsic and intrinsic setting parameters is performed, in a balance between spatial resolution and resolution. It is shown that the parametric module is an effective way to quantitatively support the choice of digital image correlation parameters in the presence of the high deformation gradient fields generated by the structure{\textendash}property relationships at the scale of observation. Under the assumption of a uniaxial tensile stress state, the spatial distribution of the radial elastic modulus across the growth rings is obtained. It is observed that the ratio of the radial modulus of elasticity between latewood and earlywood tissues can vary significantly as a function of the digital image correlation parameters. It is pointed out, however, that a convergence value can be systematically established. Effectively, earlywood and latewood stress{\textendash}strain curves are obtained and elastic properties are determined assuming the converged digital image correlation setting parameters.

}, doi = {10.1177/0309324718786351}, url = {https://doi.org/10.1177/0309324718786351}, author = {Jo{\~a}o Lu{\'\i}s Pereira and Jos{\'e} Xavier and Bahman Ghiassi and Jos{\'e} Lousada and Morais, Jos{\'e}} } @article {Lameiras2018142, title = {Pull-out behaviour of glass-fibre reinforced polymer perforated plate connectors embedded in concrete. Part II: Prediction of load carrying capacity}, journal = {Construction and Building Materials}, volume = {169}, year = {2018}, note = {n/a}, pages = {142 - 164}, abstract = {

Abstract The authors have recently proposed an innovative connector system that consists on a Glass Fibre Reinforced Polymer (GFRP) perforated plate that is embedded into Steel Fibre Reinforced Self-Compacting Concrete (SFRSCC) layers. The connection is strongly based in the mechanical interlock assured by the dowels originated from the \{SFRSCC\} passing through the holes opened on the \{GFRP\} plates. In this study, an analytical framework to evaluate the load capacity of the connections when loaded transversally was developed based on experimental pull-out tests presented in the companion paper (Part I). For a better understanding of the mechanical behaviour of the connections and to allow to make estimations of the load capacity of connection when it is conditioned by the rupture of the connector itself, pull-out pin-bearing tests with single-hole plates were executed to assess the effect of the type of \{GFRP\} on the strain distribution in the vicinity of the holes until the failure, as well as the estimated failure modes and load capacities of the connections.

}, keywords = {Bearing test, Fibre Reinforced Self-Compacting Concrete (SFRSCC), Glass-Fibre Reinforced Polymer (GFRP), PERFOFRP connector, Pull-out}, doi = {https://doi.org/10.1016/j.conbuildmat.2018.02.141}, url = {https://www.sciencedirect.com/science/article/pii/S0950061818303908}, author = {R. Lameiras and J.A.O. Barros and I.B. Valente and J. Xavier and M. Azenha} } @article {Arteiro2018438, title = {A strategy to improve the structural performance of non-crimp fabric thin-ply laminates}, journal = {Composite Structures}, volume = {188}, year = {2018}, note = {n/a}, pages = {438 - 449}, abstract = {

The enhanced mechanical performance of thin-ply laminates results from their ability to delay the onset of damage typically observed in composite materials. However, in notched structures, subcritical damage growth causes beneficial stress redistributions in the vicinity of the notch, blunting the stress concentration. Precluding these damage mechanisms, as in thin-ply laminates, may potentially lead to inferior notched responses. To obviate this limitation of thin-ply laminates, a strategy based on the combination of standard grade 0� plies and thin transverse and off-axis plies is analysed in this paper. A detailed study of the effect of 0� ply blocking is carried out, with particular emphasis on the blunting mechanisms and notched response. Tests on scaled notched panels loaded in tension, with notch sizes between 6?mm and 30?mm, show that the combination of standard grade 0� ply blocks with thin transverse and off-axis plies promotes localised fibre-matrix splitting, which acts as an important notch blunting mechanism, while preventing matrix cracking and delamination. This results in an improved notched response and superior large damage capability. It is also shown that thicker 0� ply blocks provide higher stability in composite bolted joints, while the thin transverse and off-axis plies contribute for matrix-dominated damage suppression, resulting in an improved bolt-bearing response. The improvements of the large damage capability and bolt-bearing performance are obtained without compromising the superior unnotched tensile and compressive strengths intrinsic to thin-ply laminates.

}, keywords = {Mechanical testing, Mechanically-fastened joints, Polymer-matrix composites (PMCs), Size effects, Thin plies}, issn = {0263-8223}, doi = {https://doi.org/10.1016/j.compstruct.2017.11.072}, url = {http://www.sciencedirect.com/science/article/pii/S0263822317339090}, author = {A. Arteiro and G. Catalanotti and J. Xavier and P. Linde and P.P. Camanho} } @article {Rodrigues2017183, title = {Numerical analysis of a double shear standard bolted connection considering monotonic loadings}, journal = {Engineering Structures and Technologies}, volume = {9}, number = {4}, year = {2017}, note = {

n/a

}, pages = {183-194}, publisher = {Taylor \& Francis}, abstract = {

AbstractThe behaviour of standard boltedsteel connections submitted to monotonic loads, through the use of numerical models, is presented in the current paper.The bolted connections allow speed up constructive processes in an increasingly competitive and globalized world in which the costs are a decisive factor in the development of a project. The use of computational tools in the analysis of bolted connections becomes determinant, mainly for new solutions or solutions less explored in terms of design codes.Throughout the years, bolted connections have been suffering transformations resulting from research activities performed by many authors. Rivets have been replaced by bolts, the main achievement being the pre-stressed bolts. Methodologies based on finite element analyses were proposed for double shear bolted connection. The non-linear behaviour of these connections is investigated and their performances are compared. In the numerical modelling of the bolted connection, linear elastic and elastoplastic analyzes reveal that there are two slip levels associated with local non-linearities caused by the contact pairs, which vary with clamping stresses.

}, doi = {10.3846/2029882X.2017.1414638}, url = {https://doi.org/10.3846/2029882X.2017.1414638}, author = {M.F. Rodrigues and J. Correia and B. Pedrosa and A. de Jesus and B. Carvalho and C. Rebelo and J. Xavier and R. Cal{\c c}ada} } @article {Pereira2017663, title = {ULCF assessment of X52 piping steel by means of cyclic bending tests}, journal = {Journal of Constructional Steel Research}, volume = {138}, year = {2017}, note = {

n/a

}, pages = {663 - 674}, abstract = {

Abstract Pipelines and piping components may experience large cyclic deformations during a reduced number of cycles (Ni = 1�100 cycles), when subjected to extreme cyclic loading events (e.g. hurricanes, support settlements, earthquakes). In accordance with these loading scenarios, a lateral movement can be applied to the pipeline inducing bending stresses that gradually promotes strain localization, due to progressive plastic instabilities (buckling), damage evolution and final failure. This work aims at characterizing ultra-low cycle fatigue (ULCF) behaviour of the \{X52\} piping steel under bending and local buckling state. An experimental program was carried out to derive \{ULCF\} data for smooth, notched and flat-grooved specimen geometries under cyclic bending. Furthermore, the small-scale tests were simulated in ABAQUS� with the objective of computing the parameters governing the fatigue damage models. The classical Coffin-Manson strain-life relation commonly used in the low cycle fatigue (LCF) regime is proposed to model the fatigue lives. In addition, the Xue model, particularly dependent of the monotonic fracture strain was also used for the prediction of the number of cycles until the crack initiation. The numerical data obtained with these models are compared, being achieved similar fatigue lives predictions for notched plane specimens. For the case of flat-grooved specimens which provides plain strain conditions, an overestimation from the Coffin-Manson relation was observed while the Xue model reproduces very good results for both specimens{\textquoteright} series.

}, keywords = {Cyclic bending, Experimental techniques, Numerical modelling, ULCF, X52 piping steel}, doi = {https://doi.org/10.1016/j.jcsr.2017.08.020}, url = {http://www.sciencedirect.com/science/article/pii/S0143974X17304352}, author = {J.C.R. Pereira and A.M.P. de Jesus and J. Xavier and A.A. Fernandes} } @article {Raposo20171086, title = {Characterization of the Tensile Mechanical Behavior of Wooden Construction on Materials from Historic Building}, journal = {Procedia Structural Integrity}, volume = {5}, number = {Supplement C}, year = {2017}, note = {

2nd International Conference on Structural Integrity, ICSI 2017, 4-7 September 2017, Funchal, Madeira, Portugal

}, pages = {1086-1091}, abstract = {

Abstract Ancient structures are part of the inheritance our elders left us. These historical inheritance needs to be preserved, so the historic structures need to be rehabilitated and restored, protecting the cultural patrimony and attending to the comfort and habitability required nowadays. In order to accomplish a good and economic rehabilitation is essential to study the behaviour of traditional structures elements (masonry and wood) in order to develop adequate assessment measures and techniques. In this context it was carried out an experimental campaign to characterize the tensile mechanical behavior of the woods from the �sequeiro� wood structure, integral part of the �Quinta de Lobeira de Cima� farm. This building from the 20th century is located in Minho, Portugal. Tensile Tests were carried out for two different species of wood, chestnut and oak. The tensile tests were performed to obtain the tensile strength parallel to the fibers, using the digital image correlation (DIC) for the extension measurement.

}, keywords = {Digital Image Correlation, Historic buildings, Mechanical characterization, Rehabilitation, Wood structures}, issn = {2452-3216}, doi = {https://doi.org/10.1016/j.prostr.2017.07.083}, url = {http://www.sciencedirect.com/science/article/pii/S2452321617301944}, author = {P.C. Raposo and J. Martins and J.A.F.O. Correia and M.E. Salavessa and C. Reis and J.M.C. Xavier and A.M.P. de Jesus} } @article {Silva2017124, title = {Combined analytical-numerical methodologies for the evaluation of mixed-mode (I+II) fatigue crack growth rates in structural steels}, journal = {Engineering Fracture Mechanics}, volume = {185}, number = {Supplement C}, year = {2017}, note = {

XVIII International Colloquium Mechanical Fatigue of Metals

}, pages = {124-138}, abstract = {

Abstract This paper proposes an experimental study aiming to evaluate stress intensity factors (SIFs) for fatigue cracks propagating under pure mode I and mixed-mode I+II for a S235 structural steel. Compact tension (CT) specimens with a side hole were manufactured in order to generate a stress field, ahead of the crack tip, resulting in mixed-mode fatigue crack propagation. Specimens with distinct side hole locations were submitted to fatigue tests under stress controlled conditions for a stress rati

}, keywords = {Digital Image Correlation, Fatigue crack propagation, Finite element method, Mixed-mode, Stress intensity factor}, doi = {https://doi.org/10.1016/j.engfracmech.2017.04.016}, url = {http://www.sciencedirect.com/science/article/pii/S0013794417300383}, author = {A.L.L. Silva and A.M.P. de Jesus and J. Xavier and J.A.F.O. Correia and A.A. Fernandes} } @article {Pereira2017210, title = {Direct and inverse methods applied to the determination of mode I cohesive law of bovine cortical bone using the DCB test}, journal = {International Journal of Solids and Structures}, volume = {128}, number = {Supplement C}, year = {2017}, note = {n/a}, pages = {210 - 220}, abstract = {

Abstract This work addresses the determination of the cohesive law under mode I loading of bovine cortical bone tissue using the Double Cantilever Beam (DCB) test. Direct and inverse methods were proposed to assess the cohesive laws representative of bone fracture under mode I loading. The direct method combines the evolution of the strain energy release rate under mode I loading with the crack tip opening displacement that is monitored by digital image correlation technique. According to this method, the cohesive law is obtained by differentiation of such relation with respect to the crack opening. The inverse procedure is performed through a finite element analysis including cohesive zone modelling, conjointly with a developed optimization algorithm. This identification strategy does not require a pre-established shape of the cohesive law as with the conventional inverse based procedures, which is viewed as a novelty of this work. It was concluded that both methods provide consistent results, being appellative tools concerning systematic and methodical studies dedicated to bone fracture characterization.

}, keywords = {Bovine cortical bone, Cohesive law, Double cantilever beam test, Mode I}, doi = {https://doi.org/10.1016/j.ijsolstr.2017.08.028}, url = {http://www.sciencedirect.com/science/article/pii/S002076831730392X}, author = {F.A.M. Pereira and de M.F.S.F. Moura and N. Dourado and J.J.L. Morais and J. Xavier and M.I.R. Dias} } @article {Pinto201763, title = {Dispersion and failure analysis of PLA, PLA/GNP and PLA/CNT-COOH biodegradable nanocomposites by SEM and DIC inspection}, journal = {Engineering Failure Analysis}, volume = {71}, year = {2017}, note = {n/a}, pages = {63 - 71}, abstract = {

Biodegradable polymers such as PLA have been studied for medical applications, human ligament repair is one of such cases. However, these materials can be applied in other sectors as aerospace, aeronautics, automotive, food packaging. PLA presents a relatively brittle on the mode I fracture behavior, being often blend with other biodegradable or non-degradable polymers to improve its fracture energy. For some existing applications, PLA components exhibit accumulated permanent deformation resulting from dynamic mechanical inputs, resulting on failure by laxity of parts. Aiming the improvement of PLA mechanical properties, the inclusion of carbon nanofillers into PLA matrix, in particular, CNT-COOH and GNP have been developed, due to their strong sp2 carbon-carbon bondings and their geometric arrangement that enhance mechanical properties of the polymer matrix. PLA and nanocomposites were produced by melt blending followed by compression moulding in a hot press, with small weight percentages of nanofillers added to the matrix. Nanocomposites dispersion was evaluated by SEM. Quasi static tensile tests were performed on a mechanical testing machine (Instron� ElectroPuls E1000) along with strain field measurements of specimens with centred crack with digital image correlation, revealing strain distribution along specimens.

}, keywords = {Composite(s), Failure analysis, Mechanical testing, Non-destructive testing, Static failure}, doi = {https://doi.org/10.1016/j.engfailanal.2016.06.009}, url = {http://www.sciencedirect.com/science/article/pii/S1350630716304745}, author = {V.C. Pinto and T. Ramos and A.S.F. Alves and J. Xavier and P.J. Tavares and P.M.G.P. Moreira and R.M. Guedes} } @article {Arteiro2017208, title = {Effect of tow thickness on the structural response of aerospace-grade spread-tow fabrics}, journal = {Composite Structures}, volume = {179}, year = {2017}, note = {n/a}, pages = {208 - 223}, abstract = {

The effect of ply thickness on the onset of intralaminar and interlaminar damage is extremely important for the structural response of laminated composite structures. This subject has gained particular interest in recent years due to the introduction in the market of spread-tow, ultra-thin carbon-fibre reinforcements with different configurations. In the present paper, an experimental test campaign was carried out to study the structural response of aerospace-grade plain weave spread-tow fabrics (STFs) of different areal weights. The results showed that, in spite of an apparent superior longitudinal tensile strength of the thick STF, the multidirectional thin-STF laminate exhibited an improved tensile unnotched strength over the thick-STF laminate, attributed to its damage suppression capability. However, damage suppression was also responsible for similar tensile notched strengths. In compression, the thin-STF laminate performed substantially better than the thick-STF laminate in both unnotched and notched configurations. Finally, a similar bearing response was obtained in both STF laminates, in spite of a slightly higher resistance of the thin-STF laminate to the propagation of subcritical damage mechanisms.

}, keywords = {Mechanical properties, Mechanical testing, Polymer-matrix composites (PMCs), Spread-tow fabrics}, doi = {http://dx.doi.org/10.1016/j.compstruct.2017.06.047}, url = {http://www.sciencedirect.com/science/article/pii/S0263822316330057}, author = {A. Arteiro and G. Catalanotti and J. Xavier and P. Linde and P.P. Camanho} } @article {Silva2017, title = {Fracture characterization of human cortical bone under mode II loading using the end-notched flexure test}, journal = {Medical {\&} Biological Engineering {\&} Computing}, volume = {55}, number = {8}, year = {2017}, note = {n/a}, pages = {1249-1260}, abstract = {

Fracture characterization of human cortical bone under mode II loading was analyzed using a miniaturized version of the end-notched flexure test. A data reduction scheme based on crack equivalent concept was employed to overcome uncertainties on crack length monitoring during the test. The crack tip shear displacement was experimentally measured using digital image correlation technique to determine the cohesive law that mimics bone fracture behavior under mode II loading. The developed procedure was validated by finite element analysis using cohesive zone modeling considering a trapezoidal with bilinear softening relationship. Experimental load-displacement curves, resistance curves and crack tip shear displacement versus applied displacement were used to validate the numerical procedure. The excellent agreement observed between the numerical and experimental results reveals the appropriateness of the proposed test and procedure to characterize human cortical bone fracture under mode II loading. The proposed methodology can be viewed as a novel valuable tool to be used in parametric and methodical clinical studies regarding features (e.g., age, diseases, drugs) influencing bone shear fracture under mode II loading.

}, doi = {10.1007/s11517-016-1586-6}, url = {https://doi.org/10.1007/s11517-016-1586-6}, author = {F.G.A. Silva and de M.F.S.F. Moura and N. Dourado and J. Xavier and F.A.M. Pereira and J.J.L. Morais and M.I.R. Dias and P.J. Louren{\c c}o and F.M. Judas} } @article {Kuhn2017164, title = {Fracture toughness and crack resistance curves for fiber compressive failure mode in polymer composites under high rate loading}, journal = {Composite Structures}, volume = {182}, number = {Supplement C}, year = {2017}, note = {n/a}, pages = {164-175}, abstract = {

Abstract This work presents an experimental method to measure the compressive crack resistance curve of fiber-reinforced polymer composites when subjected to dynamic loading. The data reduction couples the concepts of energy release rate, size effect law and R-curve. Double-edge notched specimens of four different sizes are used. Both split-Hopkinson pressure bar and quasi-static reference tests are performed. The full crack resistance curves at both investigated strain rate regimes are obtained on the basis of quasi-static fracture analysis theory. The results show that the steady state fracture toughness of the fiber compressive failure mode of the unidirectional carbon-epoxy composite material IM7-8552 is 165.6kJ/m2 and 101.6kJ/m2 under dynamic and quasi-static loading, respectively. Therefore the intralaminar fracture toughness in compression is found to increase with increasing strain rate.

}, keywords = {Dynamic fracture, Fiber-reinforced composites, R-curve, Size effect}, doi = {https://doi.org/10.1016/j.compstruct.2017.09.040}, url = {http://www.sciencedirect.com/science/article/pii/S0263822317320822}, author = {P. Kuhn and G. Catalanotti and J. Xavier and P.P. Camanho and H. Koerber} } @article {Subramani2016132, title = {Development and characterization of novel auxetic structures based on re-entrant hexagon design produced from braided composites}, journal = {Composites Part B: Engineering}, volume = {93}, year = {2016}, note = {n/a}, pages = {132-142}, abstract = {

Abstract This paper reports the first attempt of developing macro-scale auxetic structures based on re-entrant hexagon design from braided composite materials for civil engineering applications. Braided composite rods (BCRs) were produced and arranged as longitudinal and horizontal elements to produce three types of auxetic structures: (1) basic re-entrant hexagon structure, (2) basic structure modified by adding straight longitudinal elements and (3): structure-2 modified by changing structural angle. The influence of various material and structural parameters as well as structure type on Poisson{\textquoteright}s ratio and tensile properties was thoroughly investigated. The auxetic behaviour was found to strongly depend on the structural angle and straight elements, resulting in lower auxeticity with lower angles and in presence of straight elements. Material parameters influenced the auxetic behaviour to a lesser extent and a decrease in auxetic behaviour was noticed with increase in core fibre linear density and using stiffer fibres such as carbon. The reverse effect was observed in case of tensile strength and work of rupture. Among these structures, structure-3 exhibited good auxetic behaviour, balanced tensile properties, and high energy absorption capacity and their auxetic behaviour could be well predicted with the developed analytical model. Therefore, these novel structures present good potential for strengthening of civil structures.

}, keywords = {A. Smart materials, B. Mechanical properties, C. Analytical modelling, D. Mechanical testing, E. Braiding}, doi = {http://dx.doi.org/10.1016/j.compositesb.2016.02.058}, url = {http://www.sciencedirect.com/science/article/pii/S1359836816300129}, author = {P. Subramani and Sohel Rana and Bahman Ghiassi and Raul Fangueiro and Daniel V. Oliveira and Paulo B. Lourenco and Jose Xavier} } @article {Silva201655, title = {Effects of different environmental conditions on the mechanical characteristics of a structural epoxy}, journal = {Composites Part B: Engineering}, volume = {88}, year = {2016}, note = {n/a}, pages = {55-63}, abstract = {

Abstract With the aim of characterising a commercially available epoxy adhesive used for fibre-reinforced polymers strengthening applications, when submitted to different environmental conditions, mainly thermal (TC), freeze{\textendash}thaw (FT), and wet{\textendash}dry (WD) cycles and immersion in pure (PW) and water with chlorides (CW) for periods of exposure that lasted up to 16 months, an experimental program was carried out. Several methodologies were used in its characterization, mainly the scanning electron microscope (SEM), dynamic mechanical analysis (DMA), standard tensile tests (STT) coupled with digital image correlation (DIC). In general the results revealed that the chemical composition was not affected by the environmental conditions. Nevertheless, it was verified through \{DMA\} and \{STT\} that the modulus of elasticity and tensile strength of the epoxy adhesive increased in the TC, while the specimens submitted to \{PW\} and \{CW\} faced a high degradation in terms of its mechanical properties. Eventually, the glass transition temperature (Tg) was not affected by the environmental conditions, apart from the specimens subjected to \{TC\} and FT, presenting a higher and lower Tg, respectively, when compared with the reference specimens.

}, keywords = {B. Chemical properties, B. Mechanical properties, D. Thermal analysis, Durability, E. Thermosetting resin}, doi = {http://dx.doi.org/10.1016/j.compositesb.2015.10.036}, url = {http://www.sciencedirect.com/science/article/pii/S1359836815006666}, author = {Patr{\'\i}cia Silva and Pedro Fernandes and Jos{\'e} Sena-Cruz and Jos{\'e} Xavier and Fernando Castro and Delfim Soares and V{\'\i}tor Carneiro} } @article {Silva201672, title = {Mixed-mode I+II fracture characterization of human cortical bone using the Single Leg Bending test}, journal = {Journal of the Mechanical Behavior of Biomedical Materials}, volume = {54}, year = {2016}, note = {n/a}, pages = {72-81}, abstract = {

Abstract Mixed-mode I+II fracture characterization of human cortical bone was analyzed in this work. A miniaturized version of the Single Leg Bending test (SLB) was used owing to its simplicity. A power law criterion was verified to accurately describe the material fracture envelop under mixed-mode I+II loading. The crack tip opening displacements measured by digital image correlation were used in a direct method to determine the cohesive law mimicking fracture behavior of cortical bone. Cohesive zone modeling was used for the sake of validation. Several fracture quantities were compared with the experimental results and the good agreement observed proves the appropriateness of the proposed procedure for fracture characterization of human bone under mixed-mode I+II loading.

}, keywords = {Fracture characterization, Human cortical bone, Mixed-mode I+II, Single Leg Bending test}, issn = {1751-6161}, doi = {http://dx.doi.org/10.1016/j.jmbbm.2015.09.004}, url = {http://www.sciencedirect.com/science/article/pii/S175161611500332X}, author = {F.G.A. Silva and de M.F.S.F. Moura and N. Dourado and J. Xavier and F.A.M. Pereira and J.J.L. Morais and M.I.R. Dias} } @article {Xavier2016285, title = {On the identifiability of stiffness components of clear wood from a 3D off-axes prismatic specimen: angle orientation and friction effects}, journal = {European Journal of Wood and Wood Products}, volume = {74}, number = {3}, year = {2016}, note = {n/a}, pages = {285-290}, abstract = {

The robustness of the test method based on a single 3D off-axis prismatic specimen for the simultaneous identification of the orthotropic stiffness components of clear wood is addressed. In this method, the specimen is consecutively submitted to uniaxial compression tests along its three orthogonal axes. A data reduction based on anisotropic elasticity is applied to extract active material parameters from 3D full-field deformation measurements provided by stereo-correlation over adjacent faces. Two major limitations of this test method, directly affecting the parameter identification, are analysed and discussed: (1) off-axes angle orientation; (2) friction effects. A numerical study pointed out that radial and tangential rotations of about 29{\textdegree} and 9{\textdegree}, respectively, balances out the strain components in the specimen response. Moreover, friction can be reduced by using mass lubricant or soft material in the contact interface, realising transverse shear deformation.

}, doi = {10.1007/s00107-016-1032-3}, url = {http://dx.doi.org/10.1007/s00107-016-1032-3}, author = {J. Xavier and A. Majano-Majano and J. Fernandez-Cabo} } @article {Furtado20161, title = {Selective ply-level hybridisation for improved notched response of composite laminates}, journal = {Composite Structures}, volume = {145}, year = {2016}, note = {n/a}, pages = {1-14}, abstract = {

Abstract This work presents an experimental study on the effect of ply-level hybridisation on the tensile unnotched and notched response of composite laminates. In a first assessment, notched tests were performed on laminates with nominal ply thicknesses between 0.03 mm and 0.30 mm. From the understanding of the effect of ply thickness on the damage mechanisms that govern the notched response of laminates, the concept of ply-level hybridisation is introduced, which consists in combining plies of different grades. A uniform combination of thin and conventional plies resulted in a hybrid laminate with intermediate notched response. Selective hybridisation, where thin off-axis plies are combined with thicker 0{\textdegree} plies, resulted in a globally enhanced notched behaviour without compromising the unnotched and fatigue responses. This work clearly shows how ply-level hybridisation, when designed to trigger specific damage mechanisms, can be used to improve the notched response of composite laminates.

}, keywords = {Hybrid, Mechanical properties, Notched response, Thin-ply laminates}, doi = {http://dx.doi.org/10.1016/j.compstruct.2016.02.050}, url = {http://www.sciencedirect.com/science/article/pii/S0263822316300915}, author = {C. Furtado and A. Arteiro and G. Catalanotti and J. Xavier and P.P. Camanho} } @conference {Arteiro201513, title = {A Finite Fracture Mechanics Model for the Prediction of the Notched Response and Large Damage Capability of Composite Laminates}, booktitle = {Advances in Fracture and Damage Mechanics XIII}, series = {Key Engineering Materials}, volume = {627}, year = {2015}, note = {n/a}, month = {1}, pages = {13-16}, publisher = {Trans Tech Publications}, organization = {Trans Tech Publications}, abstract = {

A new model based on Finite Fracture Mechanics (FFMs) has been proposed to predict the open-hole tensile strength of composite laminates [1]. Failure is predicted when bothstress-based and energy-based criteria are satisfied. This model is based on an analytical solution, and no empirical adjusting parameters are required, but only two material properties: the unnotched strength and the fracture toughness. In the present work, an extension of the proposed FFMs model to predict the notched response of composite laminates with notch geometries other than a circular opening [2] is presented and applied to the prediction of size effects on the tensile and compressive notched strength of composite laminates. The present model is also used to assess the notch sensitivity and brittleness of composite laminates by means of versatile design charts and by the identification of a dimensionless parameter designated as notch sensitivity factor. A further extension of the FFMs model is proposed, which takes into account the crack resistance curve of the laminate in the model{\textquoteright}s formulation, and it is used to predict the large damage capability of a non-crimp fabric thin-ply laminate [3].

}, keywords = {Analytical Modeling, Fracture, Polymer-matrix composites (PMCs), Stress Concentration}, doi = {10.4028/www.scientific.net/KEM.627.13}, author = {A. Arteiro and G. Catalanotti and J. Xavier and P.P. Camanho} } @article {GarzonRoca2015331, title = {Effect of wet-dry cycles on the bond behaviour of concrete elements strengthened with NSM CFRP laminate strips}, journal = {Composite Structures}, volume = {132}, year = {2015}, note = {

n/a

}, pages = {331 - 340}, abstract = {

Abstract The near-surface mounted (NSM) strengthening technique is capable of effectively increase the bearing capacity of structural concrete elements. This technique which basically consists of placing \{FRP\} reinforcements inside small grooves cut in the concrete cover, has been widely investigated in terms of structural performance and ability to improve the flexural and shear behaviour of reinforced concrete beams and columns. However, little research has been carried out concerning to the \{NSM\} long-term performance and durability. Motivated by the need of increasing the knowledge on the expected durability of the \{NSM\} technique using \{CFRP\} laminates, this paper presents an experimental program in which direct pull-out tests are carried out for evaluating the bond behaviour of specimens aged through wet-dry cycles. A total of 30 specimens are tested, analysing the effect of the bond length, the groove width, the groove depth and the aging effect on the bond behaviour. Digital image correlation method is also used to identify the bond resistant mechanism developed in an element strengthened using \{NSM\} technique. Finally, using the experimental results, an analytical�numerical strategy is applied to establish the local bond stress�slip relationship.

}, keywords = {Bonding, Carbon fibre reinforced polymer, Concrete, Digital Image Correlation, Inverse analysis, \{NSM\}}, issn = {0263-8223}, doi = {http://dx.doi.org/10.1016/j.compstruct.2015.05.053}, url = {http://www.sciencedirect.com/science/article/pii/S0263822315004274}, author = {J. Garon-Roca and J.M. Sena-Cruz and P. Fernandes and J. Xavier} } @article {Ghiassi2015271, title = {Evaluation of the bond performance in FRP-brick components re-bonded after initial delamination}, journal = {Composite Structures}, volume = {123}, year = {2015}, note = {

n/a

}, pages = {271-281}, abstract = {

Abstract The bond behavior between Fiber Reinforced Polymers (FRPs) and masonry substrates has been the subject of many studies during the last years. Recent accelerated aging tests have shown that bond degradation and \{FRP\} delamination are likely to occur in FRP-strengthened masonry components under hygrothermal conditions. While an investigation on the possible methods to improve the durability of these systems is necessary, the applicability of different bond repair methods should also be studied. This paper aims at investigating the debonding mechanisms after repairing delaminated FRP-strengthened masonry components. FRP-strengthened brick specimens, after being delaminated, are repaired with two different adhesives: a conventional epoxy resin and a highly flexible polymer. The latter is used as an innovative adhesive in structural applications. The bond behavior in the repaired specimens is investigated by performing single-lap shear bond tests. Digital image correlation (DIC) is used for deeper investigation of the surface deformation and strains development. The effectiveness of the repair methods is discussed and compared with the strengthened specimens.

}, keywords = {Bond, Delamination, Digital Image Correlation, Masonry, repair, \{FRP\}}, doi = {http://dx.doi.org/10.1016/j.compstruct.2014.12.047}, author = {B. Ghiassi and J. Xavier and D.V. Oliveira and A. Kwiecien and P.B. Louren{\c c}o and B. Zajac} } @article {Xavier201527, title = {Fracture behaviour of wood bonded joints under modes I and II by digital image correlation and fibre Bragg grating sensors}, journal = {Ci{\^e}ncia \& Tecnologia dos Materiais}, volume = {27}, number = {1}, year = {2015}, note = {

n/a

}, pages = {27-35}, abstract = {

Abstract Direct identification of cohesive laws in modes I and {\.I}I\} of wood bonded joints is addressed by the double cantilever beam (DCB) and end-notched flexure (ENF) tests, respectively. Moreover, the development and extension of fracture process zone (FPZ) ahead of the initial crack tip, is analysed by means of digital image correlation (DIC) and embedded fibre Bragg grating (FBG) sensors. From \{FBG\} spectral response, the spectrum geometric mean is determined and the strain induced by wavelength variation employed to identify the initial and final stages of the FPZ. These stages are used to consistently define the cohesive laws in both modes I and II. Resistance-curves are determined from the compliance-based beam method (CBBM). Besides, the crack tip opening displacements (CTOD) are determined by post-processing displacement field provided by \{DIC\} around the initial crack tip. The strain energy release rate as a function of the \{CTOD\} are then determined for both mode I and mode II. The respective cohesive laws are reconstructed by numerical approximation and differentiation. It is concluded that the proposed data reduction scheme is effective to determine both the \{FPZ\} development phase and the corresponding cohesive laws of wood bonded joints in both mode I and mode II.

}, keywords = {Adhesion, Digital Image Correlation, fibre Bragg grating sensors., Joints/joining, Mechanical testing, Wood}, doi = {http://dx.doi.org/10.1016/j.ctmat.2015.06.001}, url = {http://www.sciencedirect.com/science/article/pii/S0870831215000439}, author = {J. Xavier and J.R.A. Fernandes and J.J.L. Morais and O. Fraz{\~a}o} } @article {Koerber2015, title = {High strain rate behaviour of 5-harness-satin weave fabric carbon-epoxy composite under compression and combined compression-shear loading}, journal = {International Journal of Solids and Structures}, volume = {54}, year = {2015}, note = {

n/a

}, pages = {172-182}, abstract = {

Abstract The strain rate dependent mechanical behaviour was studied for the common out-of-autoclave aerospace textile composite 5-harness-satin carbon�epoxy. End-loaded 15 � , 30 � and 45 � off-axis and 90 � compression tests were carried out at three different strain rate levels ( 4 � 10 - 4 s - 1 , 200 s - 1 and 1000 s - 1 ) to determine the effect of strain rate for transverse compression and combined transverse compression/in-plane shear loading. The dynamic tests were carried out on a split-Hopkinson pressure bar, where high speed photography and digital image correlation allowed a detailed study of the specimen deformation and failure process. Quasi-static reference tests were carried out on an electro-mechanical test machine using the same specimen type and a static \{DIC\} system. Pronounced strain rate effects on the axial stress�strain response were observed for all specimen types. Failure envelopes for the combined s 22 c - t 12 stress state were derived from the experimental data and compared with the maximum stress criterion, which appears well suited to approximate the experimental failure envelope at all strain rate levels. It was observed that the failure envelope was simply scaled up with increasing strain rate, while the overall shape was found to be strain rate independent.

}, keywords = {Digital Image Correlation, Failure envelopes, Plastic deformation, Polymer�matrix composites, Strain-rate effects}, doi = {http://dx.doi.org/10.1016/j.ijsolstr.2014.10.018}, url = {http://www.sciencedirect.com/science/article/pii/S0020768314003977}, author = {H. Koerber and J. Xavier and P.P. Camanho and Y.E. Essa and F. Mart{\'\i}n de la Escalera} } @article {Catalanotti2015202, title = {Measurement of the mode II intralaminar fracture toughness and R-curve of polymer composites using a modified Iosipescu specimen and the size effect law}, journal = {Engineering Fracture Mechanics}, volume = {138}, year = {2015}, note = {

n/a

}, pages = {202-214}, abstract = {

Abstract A modified Iosipescu specimen is proposed to measure the mode {\.I}I\} intralaminar fracture toughness and the corresponding crack resistance curve of fibre reinforced composites. Due to the impossibility of scaling the specimen, a modification of the classical size effect method is proposed. The calculation of the crack driving force curves is performed using the Finite Element Method. The classical Iosipescu shear feature was used and tests were coupled with digital image correlation to support the proposed approach. Experiments were performed on IM7/8552 material system and the R-curve was obtained. The steady-state value of the fracture toughness of the ply is found to be equal to R 0 ss = 34.4 \&$\#$xa0;kJ/m2.

}, keywords = {A. Polymer-matrix composites (PMCs), B. Fracture toughness, C. Analytical modelling, D. Mechanical testing}, doi = {http://dx.doi.org/10.1016/j.engfracmech.2015.03.005}, url = {http://www.sciencedirect.com/science/article/pii/S0013794415000776}, author = {G. Catalanotti and J. Xavier} } @article {Xavier201583, title = {Measuring mode I cohesive law of wood bonded joints based on digital image correlation and fibre Bragg grating sensors}, journal = {Composite Structures}, volume = {121}, year = {2015}, note = {

n/a

}, pages = {83-89}, abstract = {

Abstract This work addresses the experimental identification of mode I cohesive law of wood bonded joints. The approach combines the double cantilever beam (DCB) test with both digital image correlation (DIC) and embedded fibre Bragg grating (FBG) sensors. The spectrum geometric mean of the \{FBG\} reflected spectral response was determined, and the wavelength evolution was used to define the fracture process zone (FPZ) development phase. This evaluation allowed a consistent selection of experimental range of over which the identification procedure of mode I cohesive law is build up. Mode I crack length, Resistance-curve and cohesive law parameters are characterised and discussed. The strain energy release rate (GI) is determined from the P�d curve by the compliance-based beam method (CBBM). The crack tip opening displacement (wI) is determined by post-processing displacements measured by DIC. The cohesive law in mode I (sI�wI) is then obtained by numerical differentiation of the GI�wI relationship.

}, keywords = {Adhesion, Joints/joining, Mechanical testing, Wood}, doi = {http://dx.doi.org/10.1016/j.compstruct.2014.11.017}, author = {J. Xavier and J.R.A. Fernandes and O. Fraz{\~a}o and J.J.L. Morais} } @article {FernandezCabo2015, title = {Assessment of wire-frame analysis models of a historical planked timber arch}, journal = {Proceedings of the Institution of Civil Engineers - Structures and Buildings}, volume = {168}, number = {9}, year = {2015}, note = {n/a}, pages = {680-694}, abstract = {n/a}, doi = {10.1680/jstbu.14.00049}, url = {http://www.icevirtuallibrary.com/doi/abs/10.1680/jstbu.14.00049}, author = {J.L. Fern{\'a}ndez-Cabo and R. Widmann and M. Arce-Blanco and R. Crocetti and J. Xavier and A. Majano-Majano} } @article {Pinto2015635, title = {Comparative Failure Analysis of PLA, PLA/GNP and PLA/CNT-COOH Biodegradable Nanocomposites thin Films}, journal = {Procedia Engineering}, volume = {114}, year = {2015}, note = {

{\.I}CSI\} 2015 The 1st International Conference on Structural Integrity Funchal, Madeira, Portugal 1st to 4th September, 2015

}, pages = {635-642}, abstract = {

Abstract Biodegradable polymers such as poly(lactic) acid (PLA) have been studied for biomaterials applications such as natural human ligament replacement, however these materials could be applied to other sectors as aerospace, aeronautics, automotive, food packaging. \{PLA\} presents a relatively brittle with a mode I fracture behavior, being often blend with other biodegradable or non-degradable polymers to improve its fracture energy. For some existing applications, \{PLA\} components exhibit accumulated permanent deformation resulting from dynamic mechanical inputs, resulting on failure by laxity of parts. Aiming the improvement of \{PLA\} mechanical properties, the inclusion of carbon nanofillers into \{PLA\} matrix, in particular, CNT-COOH and \{GNP\} have been developed, due to their strong sp2 carbon-carbon bondings and their geometric arrangement that enhance mechanical properties of the polymer matrix. \{PLA\} and nanocomposites were produced by melt blending followed by compression molding in a hot press, with small weight percentages of nanofillers added to the matrix. Quasi static tensile tests were performed on a mechanical testing machine (Instron{\texttrademark} ElectroPuls E1000) along with failure analysis of specimens with centered crack with digital image correlation, revealing strain distribution along specimens.

}, keywords = {biodegradable nanocomposites, Biodegradable polymers, CNT-COOH, DIC, FTM, GNP, mechanical failure, PLA}, doi = {http://dx.doi.org/10.1016/j.proeng.2015.08.004}, url = {http://www.sciencedirect.com/science/article/pii/S1877705815016434}, author = {V.C. Pinto and Tiago Ramos and Sofia Alves and J. Xavier and Paulo Tavares and P.M.G.P. Moreira and Rui Miranda Guedes} } @article {Xavier201512, title = {Determining mode I cohesive law of Pinus pinaster by coupling double cantilever beam test with digital image correlation}, journal = {Fracture and Structural Integrity}, volume = {31}, year = {2015}, note = {n/a}, pages = {13-22}, abstract = {

The direct identification of the cohesive law in pure mode I of Pinus pinaster is addressed. The approach couples the double cantilever beam (DCB) test with digital image correlation (DIC). Wooden beam specimens loaded in the radial-longitudinal (RL) fracture propagation system are used. The strain energy release rate in mode I (GI ) is uniquely determined from the load-displacement ( P ?? ) curve by means of the compliance-based beam method (CBBM). This method relies on the concept of equivalent elastic crack length ( eq a ) and therefore does not require the monitoring of crack propagation during test. The crack tip opening displacement in mode I ? ? I w is determined from the displacement field at the initial crack tip. The cohesive law in mode I I I (? ? w ) is then identified by numerical differentiation of the I I G ? w relationship. Moreover, the proposed procedure is validated by finite element analyses including cohesive zone modelling. It is concluded that the proposed data reduction scheme is adequate for assessing the cohesive law in pure mode I of P. pinaster.

}, doi = {http://dx.doi.org/10.3221/IGF-ESIS.31.02}, url = {http://www.fracturae.com/index.php/fis/article/view/IGF-ESIS.31.02}, author = {J. Xavier and Oliveira, M. and J.J.L. Morais and de M.F.S.F. Moura} } @article {Silva2015, title = {Fracture Characterization of Human Cortical Bone Under Mode I Loading}, journal = {Journal of Biomechanical Engineering}, volume = {137}, number = {12}, year = {2015}, note = {n/a}, pages = {121004-121004}, publisher = {ASME}, abstract = {

A miniaturized version of the double cantilever beam (DCB) test is used to determine the fracture energy in human cortical bone under pure mode I loading. An equivalent crack length based data-reduction scheme is used with remarkable advantages relative to classical methods. Digital image correlation (DIC) technique is employed to determine crack opening displacement at the crack tip being correlated with the evolution of fracture energy. A method is presented to obtain the cohesive law (trapezoidal bilinear softening) mimicking the mechanical behavior observed in bone. Cohesive zone modeling (CZM) (finite-element method) was performed to validate the procedure showing excellent agreement.

}, doi = {10.1115/1.4031846}, url = {http://dx.doi.org/10.1115/1.4031846}, author = {F. Silva and M. de Moura and N. Dourado and J. Xavier and Pereira, F. and Morais, J and Dias, M. and P. Louren{\c c}o and F. Judas} } @article {Koerber2015172, title = {High strain rate behaviour of 5-harness-satin weave fabric carbon{\textendash}epoxy composite under compression and combined compression{\textendash}shear loading}, journal = {International Journal of Solids and Structures}, volume = {54}, year = {2015}, note = {n/a}, pages = {172 - 182}, abstract = {

Abstract The strain rate dependent mechanical behaviour was studied for the common out-of-autoclave aerospace textile composite 5-harness-satin carbon{\textendash}epoxy. End-loaded 15 {\textdegree} , 30 {\textdegree} and 45 {\textdegree} off-axis and 90 {\textdegree} compression tests were carried out at three different strain rate levels ( 4 {\texttimes} 10 - 4 s - 1 , 200 s - 1 and 1000 s - 1 ) to determine the effect of strain rate for transverse compression and combined transverse compression/in-plane shear loading. The dynamic tests were carried out on a split-Hopkinson pressure bar, where high speed photography and digital image correlation allowed a detailed study of the specimen deformation and failure process. Quasi-static reference tests were carried out on an electro-mechanical test machine using the same specimen type and a static \{DIC\} system. Pronounced strain rate effects on the axial stress{\textendash}strain response were observed for all specimen types. Failure envelopes for the combined σ 22 c - τ 12 stress state were derived from the experimental data and compared with the maximum stress criterion, which appears well suited to approximate the experimental failure envelope at all strain rate levels. It was observed that the failure envelope was simply scaled up with increasing strain rate, while the overall shape was found to be strain rate independent.

}, keywords = {Digital Image Correlation, Failure envelopes, Plastic deformation, Polymer{\textendash}matrix composites, Strain-rate effects}, doi = {http://dx.doi.org/10.1016/j.ijsolstr.2014.10.018}, url = {http://www.sciencedirect.com/science/article/pii/S0020768314003977}, author = {H. Koerber and J. Xavier and P.P. Camanho and Y.E. Essa and F. Mart{\'\i}n de la Escalera} } @article {Dourado2015483, title = {A New Procedure for Mode I Fracture Characterization of Cement-Based Materials}, journal = {Strain}, volume = {51}, number = {6}, year = {2015}, note = {n/a}, pages = {483-491}, abstract = {

Fracture characterization under mode I loading of a cement-based material using the single-edge-notched beam loaded in tree-point-bending was performed. A new method based on beam theory and crack equivalent concept is proposed to evaluate the Resistance-curve, which is essential to determine fracture toughness with accuracy. The method considers the existence of a stress relief region in the vicinity of the crack, dispensing crack length monitoring during experiments. A numerical validation was performed by finite element analysis considering a bilinear cohesive damage model. Experimental tests were performed in order to validate the numerical procedure. Digital image correlation technique was used to measure the specimen displacement with accuracy and without interference. Excellent agreement between numerical and experimental load{\textendash}displacement curves was obtained, which validates the procedure.

}, keywords = {cement-based materials, cohesive zone modelling, fracture toughness, mode I loading, single-edge-notched test}, doi = {10.1111/str.12165}, url = {http://dx.doi.org/10.1111/str.12165}, author = {N. Dourado and de M.F.S.F. Moura and J. Xavier and F.A.M. Pereira} } @article {Sampayo2015691, title = {Probabilistic S-N Field Assessment for a Notched Plate Made of Puddle Iron From the Eiffel Bridge with an Elliptical Hole}, journal = {Procedia Engineering}, volume = {114}, year = {2015}, note = {

{\.I}CSI\} 2015 The 1st International Conference on Structural Integrity Funchal, Madeira, Portugal 1st to 4th September, 2015

}, pages = {691-698}, abstract = {

Abstract Probabilistic fatigue models are required to account conveniently for several sources of uncertainty arising in the prediction procedures for structural details, such as the scatter in material behaviour. In this paper, a procedure to derive probabilistic S-N fields for structural details [1] is applied to a notched geometry with elliptic central hole made of puddle iron from the Eiffel bridge, based on the local approaches supported by the probabilistic ɛa{\textendash}N or Smith{\textendash}Watson{\textendash}Topper (SWT){\textendash}N fields [1,2]. This procedure suggests an extension of the fatigue crack propagation model proposed by Noroozi et al. [3,4] to structural details, in order to cover both the fatigue crack initiation and fatigue crack propagation, based on local strain approaches to fatigue. Both fatigue crack initiation and fatigue crack propagation mechanisms are accounted for in the proposed approach. The numerical results are compared with available experimental S-N fatigue data for the notched plate under consideration.

}, keywords = {Fatigue, Finite Element Modelling., Local approach, Probabilistic approach}, issn = {1877-7058}, doi = {http://dx.doi.org/10.1016/j.proeng.2015.08.011}, url = {http://www.sciencedirect.com/science/article/pii/S1877705815016501}, author = {L.M.C.M.V. Sampayo and P.M.F. Monteiro and J.A.F.O. Correia and J.M.C. Xavier and A.M.P. De Jesus and A. Fernandez-Canteli and R.A.B. Cal{\c c}ada} } @article {Silva201454, title = {Determination of cohesive laws in wood bonded joints under mode II loading using the ENF test}, journal = {International Journal of Adhesion and Adhesives}, volume = {51}, year = {2014}, note = {

n/a

}, pages = {54-61}, abstract = {

n/a

}, keywords = {Bonded joints, Cohesive laws, Digital Image Correlation, End notched flexure (ENF), Wood}, doi = {http://dx.doi.org/10.1016/j.ijadhadh.2014.02.007}, url = {http://dx.doi.org/10.1016/j.ijadhadh.2014.02.007}, author = {F.G.A. Silva and J.J.L. Morais and N. Dourado and J. Xavier and F.A.M. Pereira and de M.F.S.F. Moura} } @article {Pereira2014107, title = {Assessing wood quality by spatial variation of elastic properties within the stem: Case study of Pinus pinaster in the transverse plane}, journal = {Canadian Journal of Forest Research}, volume = {44}, number = {2}, year = {2014}, note = {n/a}, pages = {107-117}, abstract = {n/a}, author = {J. Pereira and J. Xavier and Morais, J and J. Lousada} } @article {Xavier2014142, title = {Characterisation of steel components under monotonic loading by means of image-based methods}, journal = {Optics and Lasers in Engineering}, volume = {53}, year = {2014}, note = {n/a}, pages = {142-151}, abstract = {n/a}, doi = {http://dx.doi.org/10.1016/j.optlaseng.2013.09.004}, url = {http://www.sciencedirect.com/science/article/pii/S0143816613002807}, author = {J. Xavier and J.C.R. Pereira and A.M.P. de Jesus} } @article {Xavier2014109, title = {Determining mode {\.I}I\} cohesive law of Pinus pinaster by combining the end-notched flexure test with digital image correlation}, journal = {Construction and Building Materials}, volume = {71}, year = {2014}, note = {n/a}, pages = {109-115}, abstract = {

Abstract This work addresses the direct identification of cohesive law of Pinus pinaster in mode II. The end-notched flexure (ENF) test is selected for mode {\.I}I\} loading. The strain energy release rate in mode {\.I}I\} (GII) is determined according to the compliance-based beam method (CBBM) by processing the global load�displacement curve, without requirements to monitor the crack length during test. The fracture test is coupled with digital image correlation (DIC) for the local measurement of the crack tip opening displacement in mode {\.I}I\} (wII). Using a direct method, the cohesive law in mode {\.I}I\} (sII�wII) is determined by differentiating the GII�wII relationship. The procedure is validated from both numerical, using finite element analyses including cohesive zone modelling, and experimental approaches. The methodology and accuracy on this reconstruction is discussed. It is concluded that the proposed data reduction scheme is suitable for assessing the cohesive law of P. pinaster in mode II.

}, keywords = {Cohesive law, Digital Image Correlation, End-notched flexure test, Wood}, doi = {http://dx.doi.org/10.1016/j.conbuildmat.2014.08.021}, author = {J. Xavier and Oliveira, M. and J.J.L. Morais and de M.F.S.F. Moura} } @article {Subramani2014286, title = {Development of novel auxetic structures based on braided composites}, journal = {Materials \& Design}, volume = {61}, year = {2014}, note = {n/a}, pages = {286-295}, abstract = {n/a}, keywords = {Auxetic structure, Braided composite rods, Image-based tracking, Poisson{\textquoteright}s ratio}, doi = {http://dx.doi.org/10.1016/j.matdes.2014.04.067}, url = {http://www.sciencedirect.com/science/article/pii/S0261306914003422}, author = {P. Subramani and S. Rana and D.V. Oliveira and R. Fangueiro and J. Xavier} } @article {Xavier2014929, title = {Direct Evaluation of Cohesive Law in Mode I of Pinus pinaster by Digital Image Correlation}, journal = {Experimental Mechanics}, volume = {54}, number = {5}, year = {2014}, note = {n/a}, pages = {829-840}, abstract = {n/a}, keywords = {Cohesive law, Digital Image Correlation, Double cantilever beam test, Mode I fracture mechanics, Wood}, doi = {10.1007/s11340-013-9838-y}, url = {http://dx.doi.org/10.1007/s11340-013-9838-y}, author = {J. Xavier and Oliveira, M. and P. Monteiro and J.J.L. Morais and Moura, M.F.S.F.} } @article {Arteiro2014110, title = {Large damage capability of non-crimp fabric thin-ply laminates}, journal = {Composites Part A: Applied Science and Manufacturing}, volume = {63}, year = {2014}, note = {n/a}, pages = {110 - 122}, abstract = {n/a}, keywords = {A. Laminates, B. Stress concentrations, C. Analytical modelling, D. Mechanical testing}, doi = {http://dx.doi.org/10.1016/j.compositesa.2014.04.002}, url = {http://www.sciencedirect.com/science/article/pii/S1359835X14001043}, author = {A. Arteiro and G. Catalanotti and J. Xavier and P.P. Camanho} } @article {Catalanotti2014300, title = {Measurement of the compressive crack resistance curve of composites using the size effect law.}, journal = {Composites Part A: Applied Science and Manufacturing}, volume = {56}, year = {2014}, note = {n/a}, pages = {300-307}, abstract = {n/a}, doi = {http://dx.doi.org/v10.1016/j.compositesa.2013.10.017}, author = {C. Catalanotti and J. Xavier and P.P. Camanho} } @article {Xavier20147371, title = {Moisture content effect on the fracture characterisation of Pinus pinaster under mode I}, journal = {Journal of Materials Science}, volume = {49}, number = {21}, year = {2014}, note = {n/a}, pages = {7371-7381}, publisher = {Springer US}, abstract = {n/a}, issn = {0022-2461}, doi = {10.1007/s10853-014-8375-0}, url = {http://dx.doi.org/10.1007/s10853-014-8375-0}, author = {J. Xavier and P. Monteiro and J.J.L. Morais and N. Dourado and de M.F.S.F. Moura} } @article {Pereira2014214, title = {Ultra low-cycle fatigue behaviour of a structural steel}, journal = {Engineering Structures}, volume = {60}, year = {2014}, note = {n/a}, pages = {214-222}, abstract = {n/a}, keywords = {Experimental techniques, Finite element modelling, Structural steel, Ultra low-cycle fatigue}, doi = {http://dx.doi.org/10.1016/j.engstruct.2013.12.039}, url = {http://www.sciencedirect.com/science/article/pii/S0141029614000030}, author = {J.C.R. Pereira and A.M.P. de Jesus and J. Xavier and A.A. Fernandes} } @article {Ghiassi2013340, title = {Application of digital image correlation in investigating the bond between FRP and masonry}, journal = {Composite Structures}, volume = {106}, year = {2013}, note = {

n/a

}, pages = {340-349}, abstract = {

n/a

}, doi = {10.1016/j.compstruct.2013.06.024}, author = {B. Ghiassi and J. Xavier and D.V. Oliveira and P.B. Louren{\c c}o} } @article {Fernandes2013269, title = {Determination of cohesive laws of composite bonded joints under mode II loading}, journal = {Composites Part B: Engineering}, volume = {52}, year = {2013}, note = {

n/a

}, pages = {269-274}, abstract = {

n/a

}, doi = {10.1016/j.compositesb.2013.04.007}, author = {R.M.R.P. Fernandes and J.A.G. Chousal and de M.F.S.F. Moura and J. Xavier} } @article {Xavier2013423, title = {Characterisation of the bending stiffness components of MDF panels from full-field slope measurements}, journal = {Wood Science and Technology}, volume = {47}, number = {2}, year = {2013}, note = {n/a}, pages = {423-441}, abstract = {n/a}, doi = {10.1007/s00226-012-0507-6}, author = {J. Xavier and U. Belini and F. Pierron and Morais, J and J. Lousada and M. Tomazello} } @article {Dias2013646, title = {Cohesive laws of composite bonded joints under mode I loading}, journal = {Composite Structures}, volume = {106}, year = {2013}, note = {n/a}, pages = {646-652}, abstract = {n/a}, doi = {10.1016/j.compstruct.2013.07.027}, author = {G.F. Dias and de M.F.S.F. Moura and J.A.G. Chousal and J. Xavier} } @article {Fernandes201371, title = {Comparison between neural networks and partial least squares for intra-growth ring wood density measurement with hyperspectral imaging}, journal = {Computers and Electronics in Agriculture}, volume = {94}, year = {2013}, note = {n/a}, pages = {71-81}, abstract = {n/a}, doi = {10.1016/j.compag.2013.03.010}, author = {Fernandes, A. and J. Lousada and Morais, J and J. Xavier and J. Pereira and P. Melo-Pinto} } @article {Silva2013Holz, title = {Determination of cohesive laws in wood bonded joints under mode I loading using the DCB test.}, journal = {Holzforschung}, volume = {67}, number = {8}, year = {2013}, note = {n/a}, pages = {835-959}, abstract = {n/a}, doi = {http://dx.doi.org/10.1515/hf-2013-0012}, url = {http://www.degruyter.com/view/j/hfsg.2013.67.issue-8/hf-2013-0012/hf-2013-0012.xml}, author = {F. Silva and J. Xavier and F.A.M. Pereira and Morais, J and N. Dourado and de M.F.S.F. Moura} } @article {Fernandes201359, title = {Measurement of intra-ring wood density by means of imaging VIS/NIR spectroscopy (hyperspectral imaging)}, journal = {Holzforschung}, volume = {67}, number = {1}, year = {2013}, note = {n/a}, pages = {59-65}, abstract = {n/a}, doi = {10.1515/hf-2011-0258}, author = {Fernandes, A. and J. Lousada and Morais, J and J. Xavier and J. Periera and P. Melo-Pinto} } @article {Arteiro201397, title = {Notched response of non-crimp fabric thin-ply laminates}, journal = {Composites Science and Technology}, volume = {79}, year = {2013}, note = {n/a}, pages = {97-114}, abstract = {n/a}, doi = {10.1016/j.compscitech.2013.02.001}, author = {A. Arteiro and G. Catalanotti and J. Xavier and P.P. Camanho} } @article {Arteiro2013cst, title = {Notched response of non-crimp fabric thin-ply laminates: analysis methods.}, journal = {Composites Science and Technology}, volume = {88}, year = {2013}, note = {n/a}, pages = {165-171}, abstract = {n/a}, doi = {10.1016/j.compscitech.2013.09.003}, author = {A. Arteiro and C. Catalanotti and J. Xavier and P.P. Camanho} } @article {Ercin2013736, title = {Size effects on the tensile and compressive failure of notched composite laminates}, journal = {Composite Structures}, volume = {96}, year = {2013}, note = {n/a}, pages = {736-744}, abstract = {n/a}, doi = {10.1016/j.compstruct.2012.10.004}, author = {G.H. {Ercin} and P.P. Camanho and J. Xavier and G. Catalanotti and S. Mahdi and P. Linde} } @article {Xavier2012043602, title = {Measuring displacement fields by cross-correlation and a differential technique: experimental validation}, journal = {Optical Engineering}, volume = {51}, year = {2012}, note = {n/a}, pages = {043602}, abstract = {n/a}, doi = {10.1117/1.OE.51.4.043602}, author = {J. Xavier and A.M.R. Sousa and J.J.L. Morais and V.M.J. Filipe and M. Vaz} } @article {Xavier2012207, title = {Stereovision measurements on evaluating the modulus of elasticity of wood by compression tests parallel to the grain}, journal = {Construction and Building Materials}, volume = {26}, number = {1}, year = {2012}, note = {n/a}, pages = {207-215}, abstract = {n/a}, doi = {10.1016/j.conbuildmat.2011.06.012}, author = {J. Xavier and A.M.P. de Jesus and J.J.L. Morais and J.M.T. Pinto} } @article {Sousa201187, title = {Cross-correlation and differential technique combination to determine displacement fields}, journal = {Strain}, volume = {47}, number = {s2}, year = {2011}, note = {

n/a

}, pages = {87-98}, abstract = {

n/a

}, doi = {10.1111/j.1475-1305.2010.00740.x}, author = {A.M.R. Sousa and J. Xavier and M. Vaz and J.J.L. Morais and V.M.J. Filipe} } @article {Xavier20112881, title = {Measurement of mode I and mode II fracture properties of wood-bonded joints}, journal = {Journal of Adhesion Science and Technology}, volume = {25}, number = {20}, year = {2011}, note = {n/a}, pages = {2881-2895}, abstract = {n/a}, author = {J. Xavier and Morais, J and N. Dourado and de M.F.S.F. Moura} } @article {Sousa20111402, title = {Processing discontinuous displacement fields by a spatio-temporal derivative technique}, journal = {Optics and Lasers in Engineering}, volume = {49}, number = {12}, year = {2011}, note = {n/a}, pages = {1402-1412}, abstract = {n/a}, doi = {10.1016/j.optlaseng.2011.07.007}, author = {A.M.R. Sousa and J. Xavier and J.J.L. Morais and V.M.J. Filipe and M. Vaz} } @article {Morais2010446, title = {The double cantilever beam test applied to mode I fracture characterization of cortical bone tissue}, journal = {Journal of the Mechanical Behavior of Biomedical Materials}, volume = {3}, number = {6}, year = {2010}, note = {

n/a

}, pages = {446-453}, abstract = {

n/a

}, doi = {doi:10.1016/j.jmbbm.2010.04.001}, author = {J.J.L. Morais and de M.F.S.F. Moura and F.A.M. Pereira and J. Xavier and N. Dourado and M.I.R. Dias and J.M.T. Azevedo} } @article {Koerber2010, title = {High strain rate characterisation of unidirectional carbon-epoxy IM7-8552 in transverse compression and in-plane shear using digital image correlation}, journal = {Mechanics of Materials}, volume = {42}, number = {11}, year = {2010}, note = {n/a}, pages = {1004-1019}, abstract = {n/a}, doi = {10.1016/j.mechmat.2010.09.003}, author = {H. Koerber and J. Xavier and P.P. Camanho} } @article {Catalanotti2010, title = {Measurement of resistance curves in the longitudinal failure of composites using digital image correlation}, journal = {Composites Science and Technology}, volume = {70}, number = {13}, year = {2010}, note = {n/a}, pages = {1986-1993}, abstract = {n/a}, doi = {doi:10.1016/j.compscitech.2010.07.022}, author = {G. Catalanotti and P.P. Camanho and J. Xavier and C.G. D{\'a}vila and Marques, AT} } @article {Moura2010144, title = {Mixed-mode {I/II} wood fracture characterization using the mixed-mode bending test}, journal = {Engineering Fracture Mechanics}, volume = {77}, number = {1}, year = {2010}, note = {n/a}, pages = {144-152}, abstract = {n/a}, doi = {10.1016/j.engfracmech.2009.09.014}, author = {de M.F.S.F. Moura and J.M.Q. Oliveira and J.J.L. Morais and J. Xavier} } @article {Xavier2009217, title = {Measurement of the shear properties of clear wood by the Arcan test}, journal = {Holzforschung}, volume = {63}, number = {2}, year = {2009}, note = {n/a}, pages = {217-225}, abstract = {n/a}, doi = {10.1515/HF.2009.034}, author = {J. Xavier and Oliveira, M. and Morais, J and Pinto, J.} } @article {Xavier2009b, title = {Variation of transverse and shear stiffness properties of wood in a tree}, journal = {Composites Part A: Applied Science and Manufacturing}, volume = {40}, number = {12}, year = {2009}, note = {n/a}, pages = {1953-1960}, abstract = {n/a}, doi = {10.1016/j.compositesa.2009.09.023}, author = {J. Xavier and S. Avril and F. Pierron and Morais, J} } @article {Xavier2007, title = {Novel experimental approach for longitudinal-radial stiffness characterisation of clear wood by a single test}, journal = {Holzforschung}, volume = {61}, number = {5}, year = {2007}, note = {n/a}, pages = {573-581}, abstract = {n/a}, doi = {10.1515/HF.2007.083}, author = {J. Xavier and S. Avril and F. Pierron and Morais, J} } @article {Xavier2004, title = {A comparison between the Iosipescu and off-axis shear test methods for the characterization of {\i}t Pinus pinaster Ait.}, journal = {Composites Part A: Applied Science and Manufacturing}, volume = {35}, number = {7-8}, year = {2004}, note = {

n/a

}, pages = {827-840}, abstract = {

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}, doi = {doi:10.1016/j.compositesa.2004.01.013}, author = {J.C. Xavier and N.M. Garrido and Oliveira, M. and J.L. Morais and P.P. Camanho and F. Pierron} }