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In this paper, it is explained how composite structures, made of continuous fibers embedded in a polymer matrix, are designed and analyzed in the aerospace industry. The strategy is based on the building block approach, in which the knowledge on the composite material and structure is built step by step from the coupon level up to the final full scale structure. Damage is then discussed, as it can't be ignored when composites are concerned. The approach available in the SAMCEF finite element code is then described. It is based on the continuum mechanics approach, and allows studying the progressive failure of composites in the plies and at their interface (so considering delamination). The material models are described, and their use is illustrated at the coupon level. The identification procedure for this damage models is also discussed.

In this paper, the advanced damage analysis of composite materials and structures made of continuous fibers embedded in a polymer matrix is addressed. The solution is based on the LMS Samtech Samcef finite element code, from Siemens PLM Software, which is now available in the Siemens NX CAE environment, with the specific focus of solving non-linear analysis problems for composites. Globally speaking, LMS Samtech Samcef is an implicit non-linear solver able to solve quasi-static and dynamic problems, with a comprehensive library of structural elements and kinematic joints. First, the sizing strategy based on the building block approach (pyramid of physical and virtual tests) is recalled. Applied for years in the aerospace industry, it is here extended to the automotive context. In this approach, the knowledge on the composite material and structure is built step by step from the coupon level up to the final full scale structure.

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.