In-plane shear characteristics of unidirectional glass fiber/epoxy functionally graded (FG) and nonfunctionally graded (NFG) composite laminates with statistical analysis

Abstract

In this paper, a modified Iosipescu test fixture has been designed and fabricated to investigate the in-plane shear characteristics of unidirectional glass fiber/epoxy composite laminates which are functionally graded in the thickness direction ( z). Two functionally graded and three non-functionally graded unidirectional glass fiber/epoxy composite laminates with a total fiber volume fraction of 39.9 ± 0.3% and a total thickness of 6 mm were fabricated using hand lay-up technique. The effects of unidirectional arrangement of glass fiber layers and the number of layers on shear characteristics of functionally graded and non-functionally graded composites were studied experimentally. It was observed that the layer arrangement and the number of layers have a great effect on the shear properties of the tested composites. The specimen failure modes were recorded and discussed. Two-parameter Weibull distribution function was used to statistically analyze the in-plane shear test results. The failure probability curves were plotted for all tested composites which can be used by design engineers.