Analysis of a quasi-isotropic MMC laminate using iosipescu shear test

The shear constitutive response and deformation mechanisms of a quasi-isotr opic [0/+45/-45/90](s) laminate made from TIMETAL 21S/SCS-6 MMC were invest igated using the Iosipescu test. A combination of mechanical measurement, m icrostructure analysis and finite element method were used to investigate t he inelastic deformation mechanisms of the composite. Loading-unloading exp eriments provided significant insight into the nature of damage/plasticity in the quasi-isotropic MMC laminate. Shear-induced inelastic deformation is dominant due to plasticity which is associated with slip bands, and damage which includes matrix grain boundary cracks, reaction zone cracks, debondi ng and fiber cracks. A method of finite element analysis was developed on o riented ply-stacked quasi-isotropic laminate based on an existing inelastic constitutive model from literature. The prediction for the constitutive re sponse using finite element analysis fits test data very well. The correlat ion of predicted results with experimental data shows that Iosipescu shear test is a valid method for investigating shear properties of quasi-isotropi c MMC laminates which can experience complex damage modes under pure shear loading.