The effect of different boundary conditions on crushing behavior of hat-shaped polymer composite energy absorber

Abstract

Side-door impact b eams are widely used in car doors to improve the passenger’s safety during the side impact. Fiber-reinforced polymer composite materials have a high specific strength and stiffness and are considered suitable candidate for this application. The aim of this study was to investigate energy-absorbing capacity of hat-shaped structures made from fiber-reinforced polymer composite materials at different boundary conditions. A finite element analysis model was developed using ABAQUS/Explicit code to achieve optimized fiber orientation and stacking sequence. Unidirectional E-glass fiber/polyester resin was used to construct hat-shaped beam energy absorber. Finite element analysis has revealed the optimized fiber orientations of [75/0/0/−75], [−75/0/0/75], [60/−30/30/-60], [−75/−30/75/30], [30/60/−30/−60] for quasi-static loadings, and [60/45/−45/−60], [45/−45/−60/60], [75/60/−60/−75], [−30/30/45/−45], [−75/−60/75/60] for impact loadings. Quasi-static bending as well as pendulum type impact test was carried out on specimens made with fiber orientation adopted from numerical analysis. Quasi-static bending test demonstrated that in fully clamped boundary conditions, composite layup orientation of [−75/0/0/75] showed maximum energy-absorbing capacity, but in other boundary conditions, composite layup orientation of [60/−30/30/−60] had the maximum energy-absorbing capacity. Contrarily, pendulum impact test for similar boundary conditions showed the highest energy absorption happened in fiber orientations of [−30/30/45/−45] and [−75/−60/75/60]. It was postulated that different modes of loading were the reason for this discrepancy.