多层各向异性包壳力学模型开发与应用

The multilayer SiC composites cladding composed of monolithic SiC and SiC fiber/matrix composite (SiC_f/SiC) is a popular choice for accident-tolerant fuel cladding. However, typical fuel performance analysis codes currently lack the modeling capability for the anisotropic mechanical behavior of SiC_f/SiC materials. In order to enhance the precision of mechanical calculations for composite SiC cladding in fuel performance analysis, a mechanical model was developed for multilayer anisotropic materials and integrated into the fuel performance analysis code FRAPCON4.0. Validation of the model's accuracy was conducted using a multilayer SiC cladding thermal-mechanical coupling case. The mechanical calculation capability for SiC composite cladding with orthotropic mechanical properties and multiaxial pseudoplastic behavior was achieved, and the performance of duplex-layer SiC cladding fuel elements under normal operation condition was analyzed. The developed mechanical model in this study is adaptable to arbitrary multilayer cylindrical structure fuel elements and has the capability to analyze orthotropic mechanical parameters and behaviors, rendering it applicable to various types of novel fuel element analyses.