LAUSR

Abstract To improve their energy-absorption capacity and induce failure mechanisms, the plug-type triggers of composite square tubes are designed and compared. A progressive failure model verified by the axial quasi-static loading test is proposed. Six different plug initiators including circle convex plug initiator, two types of square convex plug initiators, two types of groove-like plug initiators, and ditch-like plug initiator are given. To understand the triggering mechanism, the crashworthiness of chamfered square tubes is compared. Further, the influence of width of ditch plug-initiator towards energy-absorption characteristics and failure modes is investigated. Results show that well agreements in the failure and energy-absorption mechanisms between the simulation and experiment are identified. Three types of convex plug initiators can reduce the initial peak load and induce the out-ward petaling and splaying mode. The progressive inward-folding mode is similarly triggered by both two groove plug initiators. The ditch plug initiators are recommended as the best plug design with reasonably induced failure modes and an increase of 31.9% in total energy absorption. Comparing with non-plug initiator, square tubes crushed by narrower ditch plug initiator possess higher energy-absorption capacity, with an increase of 51.9% in SEA.