The static and dynamic axial collapse of CFRP square tubes: Finite element modelling

In the simulation works described in this paper the LS-DYNA3D explicit finite element code is used to investigate the compressive properties and crushing response of square carbon FRP (fibre reinforced plastic) tubes subjected to static axial compression and impact testing. A series of models was created to simulate some of the static and dynamic tests performed in the National Technical University of Athens using CFRP tubes featured by the same material combination (woven fabric in thermosetting epoxy resin) and external cross-section dimensions, but different length, wall thickness, laminate stacking sequence and fibre volume content. Simulation works focused on modelling the three modes of collapse (i.e. progressive end-crushing with tube wall laminate splaying, local tube-wall buckling and mid-length collapse) observed in the series of static and dynamic compression tests. Satisfactory level of agreement between calculations and test results was obtained regarding the main crushing characteristics of the tested CFRP tubes—such as peak compressive load and crash energy absorption and the overall crushing response—as the finite element models were refined several times in order to obtain optimum results.