Evolution and interaction of damage modes in fabric-reinforced composites under dynamic flexural loading

In this paper, an experimental study is performed to characterise the behaviour of fabric-reinforced composites used in sports products under large-deflection bending in Izod-type impact tests. X-ray micro computed tomography (micro-CT) is used to investigate various damage modes in the impacted CFRP specimens. It revealed that matrix cracking, delaminations, tow debonding, and fibre fracture were the prominent damage modes. Three-dimensional finite-element models are developed to study the onset, progression and interaction of some damage modes such as delamination and fabric fracture observed with micro-CT. A damage modelling technique based on a cohesive-zone method, which is more efficient than continuum damage mechanics approach, is proposed for analysis of interaction of damage modes. The developed numerical models are capable to simulate the damage mechanisms and their interaction observed in the tests. In this study, the pattern of damage formation observed in specimens was front-to-back, unlike bottom-to-top one in drop weight impact tests. The effect of boundary conditions on the dynamic response and damage evolution of composite laminates is also investigated.