Damage modeling of woven composite materials on the microscale and mesoscale

par Enrico Obert

Thèse de doctorat en Mécanique

Sous la direction de Pierre Ladevèze.

Thèses en préparation à Cachan, Ecole normale supérieure , dans le cadre de École doctorale Sciences pratiques (1998-2015 ; Cachan, Val-de-Marne) depuis le 13-09-2011 .

  • Résumé

    High-performance composite materials are becoming more and more important in the aeronautical and spatial industries. Therefore, today’s sizing methods based on experiments, which are becoming prohibitively expensive in terms of both cost and time, must evolve. The thesis has its place in this context where the objective is to reproduce numerically and accurately the physics of the phenomena involved up to complete rupture of the specimen. The most advanced research works on composites concern laminated composites made of unidirectional plies, which are also the most popular composites in the aerospace industry. Two approaches can be distinguished depending on the scale, micro or meso, of the analysis. The bridge between these two approaches recently led to the development of a micro/meso modeling scheme which meets the virtual testing challenge well and is now implemented – or in the process of being implemented – in industrial analysis codes. The modeling and analysis of woven composites up to rupture is much less advanced. Indeed, some mesomodels have been developed, but these are limited to the prediction of the initiation of a macrocrack and, therefore, are unable to predict final rupture. Of course, there have also been works on the microscale, but a true bridge between the microscale and the mesoscale is still lacking. In order to develop a model as close as possible to the physics, it is necessary to observe, understand and describe each mechanism on the most appropriate scale. Then, using relevant homogenization procedures, the information which is available on the microscale must be transferred to a coarser scale, called the mesoscale, which is suitable for structural analysis. The cornerstone is the development of a complete bridge between the microscopic and mesoscopic viewpoints.

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