8 documents found, page 1 of 1
Fracture characterisation of bone-cement bonded joints under mode I loading
Campos, Teresa Daniela Azevedo; Barbosa, M. L. S.; Olmos, Andrea Alexandra Rodrigues; Martins, Marcos Silva; Pereira, F. A. M.; de Moura, M. F. S. F.Over the years, many techniques have been developed for the stabilisation of bone fractures. The study of the adhesion of bone-to-bone cement is an important step towards the development of new immobilization systems. Although bone cement has been used for more than fifty years, very few studies have been performed regarding the evaluation of fracture properties. In this work, numerical and experimental investi...
Determination of mode II cohesive law of bovine cortical bone using direct and ...
Pereira, F. A. M.; de Moura, M. F. S. F.; Dourado, N.; Morais, J. J. L.; Xavier, J.; Dias, M. I. R.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 th...
Dimensional optimization of carbon-epoxy bars for reinforcement of wood beams
Reis, J. P.; de Moura, M. F. S. F.; Silva, F. G. A.; Dourado, N.In this work, experimental and numerical studies of wood beams reinforced with an embedded bar of carbon- fibre reinforced polymer were performed. The beams were submitted to three-point bending loading considering three different heights of embedded systems. The experimental load-displacement curves were used to validate a numerical model based on three-dimensional finite element analysis including cohesive zone ...
Mode II fracture characterization of wood using the Four-Point End-Notched Flex...
de Moura, M. F. S. F.; Silva, M. A. L.; Morais, J. J. L.; Dourado, N.This work addresses wood fracture characterization under mode II loading using the Four-Point End-Notched Flexure test. A suitable data reduction scheme based on specimen compliance, beam theory and equivalent crack model was developed with the aim of solving several disadvantages intrinsic to this fracture test. Following this methodology, crack length measurements in experimental tests required in classical p...
Fracture behavior of wood-steel dowel joints under quasi-static loading
Dourado, N.; Silva, F. G. A.; de Moura, M. F. S. F.This study analyses a common L-shape configuration formed by wood members and a thick metal plate, duly fastened with steel dowels. Four connecting arrangements were experimentally tested, considering different values of space between dowels and distance to the boundary edge, which allowed measuring the initial stiffness and moment-carrying capacity. A three-dimensional finite element model, including a trapezoid...
Mixed-mode I+II fracture characterization of a hybrid carbon-epoxy/cork laminat...
de Moura, M. F. S. F.; Cavaleiro, P. M. L. C.; Silva, F. G. A.; Dourado, N.This paper describes experimental and numerical studies addressing mixed-mode IþII fracture characterization of a carbon-epoxy/cork hybrid laminate using the Single-Leg Bending test. An equivalent crack length based data reduction scheme applied to the hybrid specimen was developed to evaluate the fracture energy. The proposed method does not require crack length monitoring during the test which is difficult to...
Surface treatment of CFRP composites using femtosecond laser radiation
Oliveira, Vitor; Sharma, S. P.; de Moura, M. F. S. F.; Moreira, R. D. F.; Vilar, R.In the present work, we investigate the surface treatment of carbon fiber-reinforced polymer (CFRP) composites by laser ablation with femtosecond laser radiation. For this purpose, unidirectional carbon fiber-reinforced epoxy matrix composites were treated with femtosecond laser pulses of 1024 nm wavelength and 550 fs duration. Laser tracks were inscribed on the material surface using pulse energies and scannin...
Direct and inverse methods applied to the determination of mode I cohesive law ...
Pereira, F. A. M.; de Moura, M. F. S. F.; Dourado, N.; Morais, J. J. L.; Xavier, J.; Dias, M. I. R.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 ...