Finite element modelling of the static axial compression and impact testing of square CFRP tubes in LS-DYNA3D

LS-DYNA3D finite element code was used for investigating the compressive properties and crushing response of square FRP (Fibre Reinforced Plastic) tubes subjected to static axial compression and impact testing. Several models were created in order to simulate a series of static and dynamic compressive tests that were performed in the National Technical University of Athens (NTUA) using carbon FRP tubes, that were 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. Modelling the three modes of collapse observed during the experimental works (i.e. progressive end-crushing with tube wall laminate splaying, local tube wall buckling and mid-length unstable crushing) was the primary goal of the simulation works. The agreement between calculations and test results regarding the main crushing characteristics of the tested CFRP tubes –such as peak compressive load and crash energy absorption– and the overall crushing response of the tubes was quite satisfactory as the finite element models were refined several times in order to achieve optimum results.