COMPRESSIVE R-CURVE OF A CARBON FIBER-EPOXY MATRIX COMPOSITE

The development of microbuckling from a sharp notch under remote compr essive loading is investigated for a unidirectional carbon-fibre/epoxy composite. Experimental measurements of the overall kink-band width c onfirm that a growing microbuckle propagates in a crack-like manner ra ther than like a dislocation. A large-scale bridging model with a crac k tip toughness and a constant bridging stress is successful in correl ating the length and width of a growing microbuckle with the remote st ress. This R-curve behaviour is modelled using a finite element analys is. The effect of matrix yield strain on the R-curve is significant, w hile the influence of the matrix strain-hardening rate and initial fib re waviness is slight. Prediction of the initiation of microbuckling i s found to be in good agreement with experimental data for a carbon-fi bre/epoxy composite. Copyright (C) 1996 Elsevier Science Limited