In-plane shear inelastic behavior of 2D-SiC/SiC composites: Experiment and simulation

Understanding the nonlinear in-plane shear behavior of 2D-SiC/SiC composites is critical for the engineering applications of advanced ceramic matrix composites. To this end, monotonic and incremental cyclic loading-unloading experiments were conducted and analyzed using several phenomenological and physics-based constitutive models, including a mechanism-based model that explicitly accounts for matrix cracking, interface debonding, and fiber bridging and bending. Particular attention was given to the evolution of the unloading modulus, elastic strain, and residual strain evolved with unloading stress. The experimental results show that the unloading modulus decreases with increasing shear stress, whereas both the elastic and residual strains increase progressively. The predictions of these parameters and the complete stress-strain response agree closely with the experimental measurements, supporting the accuracy and physical basis of the proposed analytical framework. Finally, a parametric analysis based on the mechanism-based model was performed to examine the effects of temperature, matrix crack spacing, interfacial sliding stress, and thermal misfit stress on the in-plane shear stress-strain response, providing valuable guidance for the design and performance evaluation of 2D-SiC/SiC composite structures.