Micromechanical Analysis of Mode I Crack Growth in Carbon Fibre Reinforced Polymers

Computational micromechanics models offer the possibility of analysis and quantification of the failure mechanisms that take place at the micro-scale level and are the responsible of the damage in the composite with high accuracy and with the need for very few hypotheses. Although these kind of analyses are common in current scientific literature, the analysis performed are generally limited to the stress/strain fields. This work makes use of a micromechanical model to analyze the crack tip and the cohesive zone of an interlaminar crack loaded in mode I for a carbon fiber reinforced polymer (CFRP). A periodic square fibre distribution is assumed and modelled in a FE environment and a degradation law is used to simulate damage in the matrix. This simulation allows both stress and strain quantification during crack opening and fracture mechanics analysis, such as the estimation of the critical value of the energy release rate and the quantification of the length of the cohesive zone, which is a parameter required for the application of cohesive elements.