14 documents found, page 1 of 2
A new method for the identification of cohesive laws under pure loading modes
Pereira, F.; Dourado, N.; Morais, J. J. L.; Moura, M. F. S. F. deIn this work, a new and simple methodology is proposed to identify the cohesive law of composite materials submitted to pure mode I and II loading. This methodology combines the experimental measured crack opening displacement and corresponding strain energy release rate with numerical simulation, using finite element method including cohesive zone modelling. The proposed procedure was tested and validated nume...
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...
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 characterization of human cortical bone under mode II loading using th...
Silva, F. G. A.; Moura, M. F. S. F. de; Dourado, N.; Xavier, J.; Pereira, F. A. M.; Morais, J. J. L.; Dias, M. I. R.; Lourenço, Paulo J.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 cohesiv...
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 ...
Bone fracture characterization under mixed-mode I + II loading using the MMB test
Pereira, F. A. M.; Moura, M. F. S. F. de; Dourado, N.; Morais, J. J. L.; Silva, F. G. A.; Dias, M. I. R.Fracture characterization of bovine cortical bone under mixed-mode I + II loading was performed in this work. With this aim, a miniaturized version of the mixed-mode bending testing setup was constructed. Three different mode ratios were analysed to cover a wide range of mode mixities, thus leading to an appropriate definition of fracture criterion of bovine cortical bone under mixed-mode I + II loading. A suit...
Adhesively-bonded repair proposal for wood members damaged by horizontal shear ...
Campilho, Raul; Moura, M. F. S. F. de; Ramantani, Dimitra A.; Morais, J. J. L.; Barreto, A. M. J. P.; Domingues, J. J. M. S.In this work, a repair technique with adhesively bonded carbon-epoxy patches is proposed for wood members damaged by horizontal shear and under bending loads. This damage is characterized by horizontal crack growth near the neutral plane of the wood beam, normally originating from checks and shakes. The repair consists of adhesively bonded carbon-epoxy patches on the vertical side faces of the beam at the crack...
Experimental and numerical evaluation of composite repairs on wood beams damage...
Campilho, Raul; Moura, M. F. S. F. de; Barreto, A. M. J. P.; Morais, J. J. L.; Domingues, J. J. M. S.An experimental and Finite Element study was performed on the bending behaviour of wood beams of the Pinus Pinaster species repaired with adhesively-bonded carbon–epoxy patches, after sustaining damage by cross-grain failure. This damage is characterized by crack growth at a small angle to the beams longitudinal axis, due to misalignment between the wood fibres and the beam axis. Cross-grain failure can occur i...
Buckling strength of adhesively-bonded single and double-strap repairs on carbo...
Campilho, Raul; Moura, M. F. S. F. de; Ramantani, Dimitra A.; Morais, J. J. L.; Domingues, J. J. M. S.This work reports on an experimental and finite element method (FEM) parametric study of adhesively-bonded single and double-strap repairs on carbon-epoxy structures under buckling unrestrained compression. The influence of the overlap length and patch thickness was evaluated. This loading gains a particular significance from the additional characteristic mechanisms of structures under compression, such as fibr...
Strength prediction of adhesively-bonded scarf repairs in composite structures ...
Campilho, Raul; Moura, M. F. S. F. de; Pinto, A. M. G.; Ramantani, Dimitra A.; Morais, J. J. L.; Domingues, J. J. M. S.This work reports on the experimental and numerical study of the bending behaviour of two-dimensional adhesively-bonded scarf repairs of carbon-epoxy laminates, bonded with the ductile adhesive Araldite 2015®. Scarf angles varying from 2 to 45º were tested. The experimental work performed was used to validate a numerical Finite Element analysis using ABAQUS® and a methodology developed by the authors to predict...