SiC fiber reinforced ceramic matrix composite oxidation-mechanical coupling constitutive model establishment and calculation method

The invention discloses a SiC fiber reinforced ceramic matrix composite oxidation-mechanical coupling constitutive model establishment and calculation method, O2 is modeled through diffusion of an oxide layer and a SiC/O2 oxidation reaction process, and then modulus reduction caused by oxidative damage is introduced into an orthotropic constitutive structure of SiC fibers. Secondly, a continuous damage model is adopted to describe initiation and evolution of microcracks of the ceramic matrix, O2 is modeled into a linear function of an equivalent damage factor along diffusion of the microcracks, and finally a user-defined unit subprogram based on commercial finite element software ABAQUS is written; the degree of freedom of a unit node is increased from three displacement degrees of freedom to five degrees of freedom containing SiC concentration and O2, and finite element calculation of the coupled constitutive is achieved. The invention provides a simple, convenient and intuitive method for failure analysis o