Modelling localised progressive failure of composite sandwich panels under in-plane compression

Localised progressive failure of composite sandwich panels under in-plane loads is massively seen in engineering practice, e.g. fasteners, etc. This study develops a finite element analysis (FEA) model for accounting localised progressive failure of carbon fibre reinforced polymer (CFRP) composite sandwich panels when subjected to in-plane compression. In-plane crushing experiments on the CFRP composite sandwich panels were conducted, in which the localised progressive damage was initiated by three geometric initiators, i.e., rectangular, semicircular and triangular indenters. Good agreements between the FEA and experimental results were observed for all three types of crushing scenarios. Lamina bending was found to be the predominant failure mode while other failure modes are insignificant. Besides, it was shown that the composite sandwich panels under the semicircular indenter absorbed more (∼9%) energies than those under the rectangular indenters, due to a greater contact area with more thorough crushing and cracking of the fronds when using the semicircular indenter. An ∼8% variation of the FEA results to those of tests under all loading scenarios, proving the accuracy and effectiveness using the present models for prediction of localised progressive failure behaviours. This study sets a foundation for the future design and development of protective structures or equipment with high energy-absorption capabilities.