Bidaine, B., Adam, L., Assaker, R., Chang, H. et al., "Virtual Coupon Testing of Carbon Fiber Composites for Application in Structural Analysis," SAE Technical Paper 2014-01-0809, 2014, doi:10.4271/2014-01-0809.
In the steady quest for lightweighting solutions, continuous carbon fiber composites are becoming more approachable for design, now not only used in the aerospace but also the automotive industries. Carbon Fiber Reinforced Plastics (CFRP) are now being integrated into car body structures, used for their high stiffness and strength and low weight.The material properties of continuous carbon fiber composites are much more complex than metal, especially with respect to failure; this is further complicated by the fact that a single part is typically made from stacks of several unidirectional plies, each with a different fiber orientation. Hence failure occurs because of various mechanisms taking place at the ply level (matrix cracking, fiber breakage, fiber-matrix debonding) or between the plies (delamination). These mechanisms remain not fully understood and are investigated through experimental and virtual testing.To predict composite failure, we have developed advanced simulation strategies combining finite element analysis (FEA) and nonlinear micromechanical material modeling. In particular, we implemented progressive failure models such as Matzenmiller-Lubliner-Taylor to maintain the validity of the analysis after the first elements have failed. In addition, we enriched these models with inputs computed at the microscopic scale.Multi-scale modeling decomposes the macroscopic mechanical state between fibers and resin, enables the definition of per-phase failure criteria and provides access to macroscopic or microscopic stiffness degradation. In this paper, we will show how micro-mechanically-based progressive failure models enable virtual coupon testing for application in structural analysis.