Modeling of mechanical behavior and design criteria for SiCf/SiC composite structures in fusion reactors

Silicon carbide composites are the primary composite materials being evaluated and developed world-wide for fusion structural applications. Their use as structural material involves however the adoption of appropriate design methodologies capable to take into account their complex non linear mechanical behavior. Some behavioral models developed specifically for SiCf/SiC composites and already available in literature are reviewed in this paper. They have been evaluated with respect to the possibility of implementation in FEM codes and keeping in mind fusion-specific issues. One of them has recently been implemented in the FEM code CASTEM 2000. At the same time, appropriate resistance criteria are necessary to correctly assess the potential advantages of SiCf/SiC composites over more common metallic materials. A new resistance criterion has then been defined and is presented in this work. Examples of application of the improved design analysis methodology are given throughout the paper.