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Stability condition for the evaluation of damage in three-point bending of a laminated composite
Mokaddem Allel,Alami Mohamed,Boutaous Ahmed 국제구조공학회 2013 Steel and Composite Structures, An International J Vol.15 No.2
The study of the tensile strength of composite materials is far more complex than analysis of the properties of elasticity and plasticity. Indeed, during mechanical loading, micro-cracks in the matrix, the fibers break, debonding of the interfaces are created. The failure process of composites is of great diversity and cannot be described if even we know: the strength criterion of each individual component, the state of stress and strain in the material, the propagation phenomena cracks in the structure and nature of the interface between the matrix and the reinforcement. This information is only partially known and the obtained by the analysis of a stress limit beyond which there is destruction of the material is almost impossible. To partially process the issue, a solution lies in a mesoscopic approach of seeking a law to locate the ultimate strength of the material for a plane stress state. Tests on rectangular plates in bending PEEK/APC2 and T300/914 three were made and this in order to validate our approach, the calculation has been implemented in a nonlinear finite element code (Castem 2000), in order to make comparison with the numerical results. The results show good agreement between numerical simulation and the two materials; however, it would be interesting to consider other phenomena in the criterion.
Mohammed Belkheir,Mohamed Alami,Allel Mokaddem,Bendouma Doumi,Ahmed Boutaous 한국섬유공학회 2022 Fibers and polymers Vol.23 No.10
Compared to Silica Optical Fibers, Polymethyl Methacrylate Polymer Optical Fibers (POFs) present a highattenuation and dispersion properties for long distances. However, they have more benefits in terms of mechanical andthermal characteristics such as viscoelasticity, strain and bending that allow them to be widely used for various life domainslike biomedical and sensing applications. This paper studies and analyzes the effect of humidity on the fiber-matrix interfacedamage for composite materials based on (Topas/PMMA, Topas-Zeonex/PMMA and Zeonex/PMMA) using geneticapproach based on Weibull probabilistic formalism and the law of diffusion. The results gained show that the mechanicalstresses applied to the three composite materials provoke damage to the interface with different levels, lower for Topas/PMMA, medium for Topas-Zeonex/PMMA and higher for Zeonex/PMMA. In the other hand, the fiber-matrix interface ofTopas/PMMA composite is not influenced by humidity compared to other interfaces of Topas-Zeonex/PMMA and Zeonex/PMMA composite materials. Our present results are closely similar to those found by Leal et al.