A FEM method for prediction of energy absorption capability of crashworthy polymer composite materials

Crashworthy performance of composite materials is commonly expressed in terms of specific energy absorption capability. It is determined by progressive crushing of tubular composite specimen by applying axial compressive load. The specific energy absorption capability of composite material is calculated using the mean crush load obtained from the compression test. In this work efforts have been made to develop a finite element calculation method for predicting the mean crush load. For analysis purpose, we considered filament wound glass fiber/epoxy and woven glass fiber/epoxy composite tubes which crush by splaying mode. Based on the microscopic observations, various microfracture processes in the splaying mode crush zone were identified. Longitudinal cracking of tube wall is relatively important compared to other fracture processes. The contribution of longitudinal cracking of tube wall on the mean crush load and energy absorption capability of composite material was estimated. The predicted values were in reasonably good agreement with the experimental results.