In-plane shear constitutive model for 2D-C/SiC composites

Abstract

In order to characterize in-plane shear behavior of 2D-C/SiC composites，a macroscopic cross-ply laminate model and a microscopic mini-composite model were proposed，considering damage mechanisms such as matrix cracking，interface debonding，and fiber bridging and bending. By introducing the influence of thermal misfit stress and characterizing both the unloading elastic strain and residual strain，a temperature-dependent in-plane shear constitutive model for the material was established. In-plane shear tests with 2D-C/SiC composites were performed at room temperature to validate the model. It is found that the residual strain and elastic strain increase while the unloading modulus decreases gradually with increasing shear stress. The model was then used to simulate the shear behavior. The results show that the predictions of elastic strain，residual strain，unloading modulus， and apparent stress-strain relationship are all consistent with the tested data，which preliminarily illustrates the reasonability and accuracy of the analytical model. On this basis，the in-plane shear stress-strain curves of 2D-C/SiC composites at different temperatures are presented，providing a reference for thermal structure design.

Keywords

• 2d-c/sic composites
• in-plane shear
• thermal misfit stress
• high-temperature property
• damage mechanism