Combined Experimental and Modeling Approaches for Strength Analysis of 3D Woven Composites: From Elementary Coupons to Complex Aeronautical Structures

New generations of 3D woven composite materials have been recently developed to be used in aeronautics as an alternative to the classical laminated composite materials, for structures exposed to impact. Therefore, it has been necessary to determine precisely the damage and failure scenarios for such materials subjected to different kinds of loadings through a large experimental testing campaign performed at Onera on unnotched coupons. These tests have been multi-instrumented to understand the different damage and failure mechanisms encountered in 3D woven composite materials. Based on these observations, a model, named Onera Damage Model for Polymer Matrix Composites (ODM-PMC), has been developed specifically for such materials. This non-linear material approach takes into account the different observed sources of non-linearity (viscoelasticity of the matrix, in–plane matrix damage, interyarn debondings and fiber yarn failures) and has been validated through comparisons with available tests on unnotched specimens. Moreover, the predicted failure loads, obtained with the ODM-PMC model, on plates containing different kinds of geometrical singularities, such as a hole or a milled groove, have been compared successfully to multi-instrumented test results also performed at Onera . Finally, the ODM-PMC model has been applied to large 3D woven composite structures, quite representative of real industrial components. The predicted damage and failure scenarios seem to be relevant as compared to data available in the literature. Moreover, the obtained computational times are compatible with usage in an industrial environment. Therefore, it has been demonstrated that this approach, implemented in a commercial finite element code, could be used in design offices in aeronautical industries.