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The strength characteristic of CFRP composite materials often is dependent on the internal micro-structural fracture mode. Therefore, in order to precisely predict this strength, each fracture mode and its mutual influence must be taken into account in a simulation. In this paper, intra-ply fracture progression and load characteristics of a cyclic loading test were analyzed, utilizing a material model proposed by Ladeveze et al. The model can evaluate different fracture modes and the stiffness degradation resulting from them. The analyzed results were compared with actual test results to confirm the validity of the analysis. Another analysis was performed without considering the mutual influence of the different fracture modes, and the results were compared to discuss the necessity of the coupling.

We are in the context of the analysis of carbon fiber reinforced plastics (CFRP) high-pressure vessel (COPV - Composite Overwrapped Pressure Vessel) manufactured by filament winding (FW). Classically, the parameters of material models are identified based on flat laminate coupons with specific predetermined fiber orientations, and based on standards like the ones of ASTM relevant for flat coupons. CFRP manufactured by FW has a unique and complex laminate structure, which presents curvatures and ply interlacements. In practice, it is important to use coupons produced with the final manufacturing process for the parameter identification of the material models; if classical coupons produced by e.g. ply lamination are used, the effect of FW structure cannot be accounted for, and cannot be introduced in the material models. It is therefore essential to develop an approach to create representative flat coupons based on the FW process.