The progressional approach to interfacial failure in carbon reinforced composites: elasto-plastic finite element modelling of interface cracks

摘要

A rigorous stage-by-stage 'Progressional Approach' to interfacial failure is described in which elasto-plastic finite element (FE) analysis has been used to model the initiation and subsequent propagation of an interface crack in a tensile loaded single carbon fibre composite specimen. The non-linear effects of frictional stress transfer across the debonded interface and the residual stresses thermally induced due to curing have been included. Such effects were found to play a key role in determining the reinforcement efficiency of the fibre as failure at the interface progressed, during incremental loading. Previously published laser Raman spectroscopy measurements for fibre stress distributions have been compared with the FE predictions, for a number of stress levels in the composite. Good correlation was obtained with the experimental data, for a number of interface crack lengths and for a coefficient of friction 0.8-0.9 at the cracked interface. The fibre stress distributions obtained were found to be characteristic of this mode of interfacial failure.