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Xavier, J., J. C. R. Pereira, and A. M. P. de Jesus. "Characterisation of steel components under monotonic loading by means of image-based methods." Optics and Lasers in Engineering. 53 (2014): 142-151. AbstractWebsite
Xavier, J., U. Belini, F. Pierron, J. Morais, J. Lousada, and M. Tomazello. "Characterisation of the bending stiffness components of MDF panels from full-field slope measurements." Wood Science and Technology. 47 (2013): 423-441. Abstract
Raposo, P., J. Martins, J. Correia, Maria E. Salavessa, Cristina Reis, José Xavier, and Abilio M. P. de Jesus. "Characterization of the mechanical behaviour of wooden construction materials from quinta lobeira de cima." International Journal of Structural Integrity. 9 (2018): 396-410. AbstractWebsite

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.

Raposo, P. C., J. Martins, J. A. F. O. Correia, M. E. Salavessa, C. Reis, J. M. C. Xavier, and A. M. P. de Jesus. "Characterization of the Tensile Mechanical Behavior of Wooden Construction on Materials from Historic Building." Procedia Structural Integrity. 5 (2017): 1086-1091. AbstractWebsite

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.

Dias, G. F., M. F. S. F. de Moura, J. A. G. Chousal, and J. Xavier. "Cohesive laws of composite bonded joints under mode I loading." Composite Structures. 106 (2013): 646-652. Abstract
Silva, A. L. L., A. M. P. de Jesus, J. Xavier, J. A. F. O. Correia, and A. A. Fernandes. "Combined analytical-numerical methodologies for the evaluation of mixed-mode (I+II) fatigue crack growth rates in structural steels." Engineering Fracture Mechanics. 185 (2017): 124-138. AbstractWebsite

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

Pinto, V. C., Tiago Ramos, Sofia Alves, J. Xavier, Paulo Tavares, P. M. G. P. Moreira, and Rui Miranda Guedes. "Comparative Failure Analysis of PLA, PLA/GNP and PLA/CNT-COOH Biodegradable Nanocomposites thin Films." Procedia Engineering. 114 (2015): 635-642. AbstractWebsite

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™ ElectroPuls E1000) along with failure analysis of specimens with centered crack with digital image correlation, revealing strain distribution along specimens.

Fernandes, A., J. Lousada, J. Morais, J. Xavier, J. Pereira, and P. Melo-Pinto. "Comparison between neural networks and partial least squares for intra-growth ring wood density measurement with hyperspectral imaging." Computers and Electronics in Agriculture. 94 (2013): 71-81. Abstract
Xavier, J. C., N. M. Garrido, M. Oliveira, J. L. Morais, P. P. Camanho, and F. Pierron. "A comparison between the Iosipescu and off-axis shear test methods for the characterization of ıt Pinus pinaster Ait." Composites Part A: Applied Science and Manufacturing. 35 (2004): 827-840. Abstract


Sousa, A. M. R., J. Xavier, M. Vaz, J. J. L. Morais, and V. M. J. Filipe. "Cross-correlation and differential technique combination to determine displacement fields." Strain. 47 (2011): 87-98. Abstract