Validation of full 3D and equivalent tape laminate modeling of plasticity induced non-linearity in 2 × 2 braided composites

Fiber reinforced polymer matrix braided composites exhibit considerable non-linear response. Plasticity induced non-linear behavior of 2 × 2 braided composites was investigated using a two scale finite element modeling approach based on Hill’s yield function for orthotropic materials. The analysis was validated by comparing the macroscopic stress–strain predictions for a variety of 2 × 2 biaxial braids with experimental data. Experimental results were also compared with equivalent tape laminate analyses, which required only three elements and much less computational time. All the braids show considerable plasticity induced non-linearity. Predictions of both full 3D and equivalent tape laminate plastic analyses agree reasonably well with the experiments. Performance of braided composites was compared with tape laminates and it was seen that equivalent tape laminates have a better performance than their braid counterparts in terms of longitudinal modulus, but in terms of percentage moduli degradation due to plasticity, both braids and tapes have similar performance.