Lateral crushing behavior of novel carbon fiber/epoxy composite bidirectional self-locked thin-walled tubular structure and system

Bidirectional self-locked structure has important significance in energy absorption protection, especially complex loading absorbing energy. This paper reports on the lateral crushing behavior of novel carbon fiber/epoxy composite bidirectional self-locked thin-walled tubular structure (BST) and system (BSTS), as well as some improved bidirectional self-locked thin-walled tubular structures and systems. The lateral crushing behaviors of BST and BSTS were investigated by experiment and finite element analysis. It was found that the specific energy absorption (SEA) of BSTS was inferior to BST, which indicated the assembling system weakened energy absorption. The simulated results indicated that changing stacking sequence of carbon fiber/epoxy prepreg had not significantly effect on crushing performance of BST. Finally, the improved bidirectional self-locked thin-walled tubular structures and systems were designed and tested. The improved design enabled to enhance 139.9% in the crushing force efficiency (CFE) (specifically from 33.3% to 79.9%) and 27.5% in the SEA (from 4.0 J/g to 5.1 J/g). It was worth mentioning that the bidirectional self-locked system with PMI foam-filled enhanced 20.8% than bidirectional self-locked thin-walled tubular structure with PMI foam-filled in the SEA (from 5.3 J/g to 6.4 J/g).