Effect of strain rate on the failure mechanisms and energy absorption in polymer composite elements under axial loading

This paper is concerned with the development of finite element (FE) codes and design tools suitable for detailed fine scale modeling of crush behaviors observed in composite crashworthy structures under dynamic loading regimes. A numerical modeling methodology previously developed to model the quasi-static crush behavior is used here to replicate the dynamic crush behaviors and accurately simulate identified energy absorbing mechanisms determined from experimental work. The methodology undertaken consists of firstly, the numerical modeling of damage development in the FRP composite laminate. To capture the strain rate effects on the crush response, material models were formulated for each loading regime from experimental coupon tests under quasi-static and dynamic loads to retrieve input parameters for the material models. The second feature of the numerical methodology focuses on the implementation of innovative numerical triggers into the numerical models. These numerical triggers were designed to replicate in the numerical model, the initiation, propagation and complex failure mechanisms of the crush responses observed in the experimental crush tests.