Study of the influence of the type of matrix used in carbon-epoxy composites on fatigue delamination under mode III fracture

Abstract

The fatigue delamination process of three different aeronautical quality composites subject to mode III fracture loading is studied experimentally in this paper with the aim of analysing the effect of the type of matrix used under this fatigue fracture mode. In all cases, the main difference between the composite materials considered in this study is the type of epoxy resin used as the matrix.The test method used to produce the delamination process under mode III fracture is known as the Longitudinal Half Fixed Beam (LHFB) method, used in previous studies by the authors, which was shown to be a valid method for generating the delamination process in composite sheet materials subject to mode III fatigue loading.The experimental data from the fatigue tests were treated with a probabilistic model based on the Weibull distribution. This model facilitates the identification of relevant aspects of the fatigue behaviour of these materials, such as the estimation of fatigue strength for periods of time greater than those tested here, as well as the reliability of the results.The results thus obtained reflect important differences in the fatigue behaviour of the materials under study, the type of matrix being the predominant parameter of the fracture process under mode III loading.