A physically based thermo‐elastoplastic constitutive model for braided CMCs‐SiC at ultra‐high temperature. Issue 3 (18th November 2021)

• Record Type: Journal Article
• Authors: Chen, Yanfei; Ai, Shigang; Wang, Pan; Fang, Daining
• Is Part Of: Journal of the American Ceramic Society. Volume 105:Issue 3(2022)
• Page Start: 2196
• Page End: 2208
• Publication Date: 2021-11-18
• Subjects: CMCs‐SiC -- nonlinearity -- thermo‐elastoplastic constitutive model -- ultra‐high temperature; Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.18213
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract: Complex microstructure and multiple internal microcrack propagation of braided silicon carbide ceramic matrix composites (CMCs‐SiC) make their mechanical behavior remarkably nonlinear. Still, few models have been developed at ultra‐high temperature due to the challenge to incorporate detailed micromechanisms of nonlinearity into the formulation. Based on the observations of fracture morphologies of previous experiments of CMCs‐SiC under different stress states and current on‐axis tensile experiments of 2D C/SiC composites at ultra‐high temperature, some assumptions are proposed. Then, a physically based constitutive model at ultra‐high temperature is established within the thermo‐elastoplastic framework. The novelty of this model is that we proposed a thermal yield criterion, which considers the material orthotropy, tension‐compression asymmetry, unilateral crack closure effect, and temperature effect. The thermal hardening effect is a distinctive phenomenon for CMCs‐SiC in vacuum and is described using an improved Johnson–Cook model. The proposed model is implemented using a return mapping algorithm. The results show that the model predictions of stress–strain relationships agree well with experimental data at different stress states and different temperatures.