Compared to tensile and compressive strength

the shear strength of engineering materials is generally lower. However

shear is also one of the common load forms encountered in the service conditions of aerospace loadbearing structures and has a significant impact on load-bearing performance of structures. Therefore

the in-plane shear constitutive relationship and ultimate strength of materials are undoubtedly key fundamental parameters for structural design and performance evaluation. This paper focuses on a typical type of thermal structural material

namely silicon carbide ceramic matrix composites (CMC-SiC)

reviews the in-plane shear stress-strain behavior

multi-scale damagefailure modes and evolution mechanisms

macroscopic phenomenological constitutive models

and physical-mechanical models considering micro-damage mechanisms. It also briefly discusses the primary factors influencing the in-plane shear performance of CMC-SiC materials

identifies the shortcomings of current research

and outlines future research directions. The aim is to promote the comprehensive characterization

theoretical analysis and model evaluation of the mechanical properties of advanced ceramic-matrix composites

thereby providing support for the design and assessment of load-bearing performance of thermal structures.