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Dourado, N., M. F. S. F. de Moura, J. Xavier, and F. A. M. Pereira. "A New Procedure for Mode I Fracture Characterization of Cement-Based Materials." Strain. 51 (2015): 483-491. AbstractWebsite

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–displacement curves was obtained, which validates the procedure.

Xavier, J., J. Morais, and F. Pereira. "Non-linear shear behaviour of bovine cortical bone by coupling the Arcan test with digital image correlation." Optics and Lasers in Engineering. 110 (2018): 462-470. AbstractWebsite

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.

Arteiro, A., G. Catalanotti, J. Xavier, and P. P. Camanho. "Notched response of non-crimp fabric thin-ply laminates." Composites Science and Technology. 79 (2013): 97-114. Abstract
Arteiro, A., C. Catalanotti, J. Xavier, and P. P. Camanho. "Notched response of non-crimp fabric thin-ply laminates: analysis methods." Composites Science and Technology. 88 (2013): 165-171. Abstract
Xavier, J., S. Avril, F. Pierron, and J. Morais. "Novel experimental approach for longitudinal-radial stiffness characterisation of clear wood by a single test." Holzforschung. 61 (2007): 573-581. Abstract
Rodrigues, M. F., J. Correia, B. Pedrosa, A. de Jesus, B. Carvalho, C. Rebelo, J. Xavier, and R. Calçada. "Numerical analysis of a double shear standard bolted connection considering monotonic loadings." Engineering Structures and Technologies. 9 (2017): 183-194. AbstractWebsite

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.