Parametric study of crushing parameters and failure patterns of pultruded composite tubes using cohesive elements and seam: Part II - Multiple delaminations and initial geometric imperfections

Part I presented the circumferential central delamination and triggering modelling of composite tubes and their influence on predicting the peak crush load and the corresponding energy absorption. The knowledge of failure patterns is very important for the design architecture of an energy absorbing element and its placement in the structure. In this study, the failure patterns of pultruded circular and square cross sectional glass polyester composite tubes were evaluated with pre-defined seams for an axial impact loading case. Furthermore, this paper demonstrates the importance of considering multiple delaminations to predict the appropriate energy absorption of composite tubes using cohesive elements. The influence of correct numerical modelling of triggering (especially 45° edge chamfering) on the peak crush load of the composite tubes is proved with multiple layers of shell elements. The effect of initial geometric imperfections on the energy absorption, peak crushing load and the deformation pattern of pultruded glass polyester composite tubes is also studied. In order to address the importance of above factors, a comprehensive numerical investigation was carried out with multiple layers of shell elements and with cohesive elements. Finally, the deformation patterns, peak crushing load and the corresponding energy absorption were compared with experimental results [1].