Analysis of impact-induced damage and delamination in the composite shell of a helmet

The impact energy absorption by helmets is of vital importance to the safety of motorcyclists during accidents. The paper is concerned with the study of damage and delamination, which are the principal modes of failure and energy absorption, in a composite shell and their influence on the impact performance of a helmet. Numerical simulations were conducted with different composite shells made of cross-ply laminate, woven fabric, and glass mat. The effectiveness of the numerical model is established using available experimental results from the literature. Hashin failure criteria and cohesive zone model (CZM) were used for predicting the in-plane damage and delamination in composite plies, respectively. An interface layer having a bilinear relationship between traction and relative displacement was placed between the plies of the composite shell to predict the delamination. The influence of damage and delamination in shells made of composite materials on impact-induced forces is evaluated and their performance is compared with helmet shells made of Acrylonitrile Butadiene Styrene (ABS).