Study on Mechanical Properties of SiC_f/SiC Nuclear Cladding Tube Based on Braiding Process Simulation and Multi-scale FE Analysis

The production of silicon carbide fiber reinforced silicon carbide ceramic composite (SiC_f/SiC) cladding tube fiber preforms based on braiding process and PIP method is one of the focuses in research at present. In the spent fuel reactor, in order to improve the efficiency of the heat exchange, the wall thickness of the clad should be less than 0.75 mm while withstanding a complex load condition, which leads to a great challenge to the structure design of the four-meter-long cladding tube. Therefore, a finite element model dealing with the complex structure of composite materials for braiding process as well as multi-scale safety analysis is necessary. Based on the contact algorithm, the finite element model for braided process including certain processing parameters was established. Moreover, the influence of parameters, i.e. fiber volume fraction and mechanical properties of the constituents was investigated by meso- and macro-model. Compared with the tube model constructed by the traditional laminated theory method, it revealed that the latter has overestimated the torsional strength by 69%, which raised a extremely high risk in application for the clading tubes. This article aims to preliminarily explore the optimization of complex silicon carbide composite material structures through joint process simulation and multi-scale simulation design, and predict mechanical properties such as strength and modulus to reduce expensive preparation and experimental costs. It provides a reliable tool for future strength design of complex silicon carbide fiber reinforced silicon carbide composite material structures.