Finite element analyses of compressive behaviors of biaxial warp-knitted composite material under various strain rates with a simplified geometrical model

This paper reports the compressive behaviors of biaxial warp-knitted (BWK) composite material under compression with various strain rates. The compression stress–strain curves and the failure modes along three orthogonal directions were obtained from split Hopkinson pressure bar (SHPB) apparatus. A finite element analysis (FEA) model based on a simplified model of BWK composite was also carried out to verify the experimental results. In the simplified model, an equivalence resin (ER) combined tricot yarns with resin, and the stiffness matrix was derived from the mechanical parameters of the tricot yarns and the resin. A good agreement between experimental and FEA demonstrates that the simplified method is applicable of modeling the high strain-rate behaviors. By comparing the experimental damage morphologies with the damage development and morphologies observed from the model, it was found that the FEA model offers a better understanding to the compression damage mechanisms. The model can also be extended to design the impact performance of the BWK composite with high efficiency.