On axial crushing behavior of double hat-shaped CFRP and GFRP structures

Abstract

This study aimed to investigate the energy-absorbing mechanisms of composite structures subjected to quasi-static and dynamic axial crushing loads. Double hat-shaped composite tubes were prepared using carbon fiber-reinforced polymer (CFRP) and glass fiber-reinforced polymer (GFRP) composite materials. The results indicated that these composite tubes exhibited a progressive end-crushing mode and had a comparable load-carrying capacity at a crushing velocity of 2 mm/min. When the loading rate was increased to 6.1 m/s, a 23.3% reduction in the energy absorption of the CFRP structures was observed; whereas the energy absorption of the GFRP structures remained relatively constant. A stacked-shell finite element model, which considered the effects of strain rate on intra-layer and inter-layer properties, was developed to simulate the axial crushing behavior of the CFRP and GFRP tubes. The predictions made by the finite element model were found to correlate well with the tested crushing process, force–displacement curves, and final failure mode. The mechanical properties of the composite materials were also observed to play a critical role in the energy-absorbing mechanisms, contributing to the distinct crushing responses of the CFRP and GFRP structures. The results of this study are expected to help clarify the differences in the energy-absorbing mechanisms between CFRP and GFRP tubes, thereby contributing to the crashworthiness design of composite energy-absorbing structures.