Comparative study on aluminum/GFRP/CFRP tubes for oblique lateral crushing

Abstract

Thin-walled composite structures are increasingly used in vehicles attributed to their lightweight and high energy-absorbing capacity. However, understanding crushing behavior of tubal structures made of different materials for lateral impact loading from different directions is fairly limited, which restricts their further applications. This study aimed to investigate the oblique lateral crashworthy characteristics of thin-walled circular tubes with aluminum, glass fiber reinforced polymer (GFRP) and carbon fiber reinforced polymer (CFRP) materials by experimental, numerical and analytical methods. Thin-walled tubes were considered to bear the combined lateral compression and shear loading radially through two parallel rigid platens from the oblique angles of 0°, 10°, 20° and 30° to the horizontal direction, respectively. The effects of loading angles on crushing process, failure modes and crashworthiness indicators were quantified. Similar deformation patterns of each type of the tubes can be observed under these different loading angles, where frictional shear was found to be of limited effect on the deformation mode. With increase in loading angle, initial crushing force decreased, also the energy absorption of GFRP tube decreased whilst those of aluminum and CFRP tubes increased as seen from a prolonged process in the energy absorption-displacement curve. The specific energy absorption ( S E A ) of the aluminum, GFRP and CFRP tubes ranged from 2.36 to 2.62 J/g, 1.1 to 0.88 J/g and 0.79–0.96 J/g, respectively; and their corresponding crushing force efficiencies ( C F E ) ranged from 1.18 to 1.49, 0.74 to 0.59 and 0.6 to 0.65, respectively. To further explore the crushing behavior, finite element models were established and validated against the experiments. Finally, an analytical model was derived to predict the crashworthiness of thin-walled tubes under oblique lateral crushing. The study is expected to provide insights and guide to design of crashworthy structures for oblique lateral loading. • The oblique lateral crushing behavior of thin-walled aluminum, GFRP and CFRP tubes. • The FE and theoretical models of aluminum, GFRP and CFRP tubes under oblique lateral crushing. • The oblique lateral crushing performance and energy absorption mechanism of thin-walled aluminum, GFRP and CFRP tubes.