Comparative study of predictive FE methods for mechanical properties of nuclear composites

Carbon fiber reinforced carbon (C/C) composites are candidate materials for plasma facing components in experimental fusion reactors such as: the ITER; the JT-60 – a Tokamak fusion test facility (JAEA); and for control rods in the next generation fission reactors. Therefore, determining their thermo-mechanical properties under irradiation is essential for safe design-cum-operation of future reactors. Development of reliable models which can predict such materials’ behavior is of massive advantage against the conventional experimental verification which is hugely expensive and time-consuming. Three-dimensional finite element (FE) methods are used here for predicting Young’s modulus of two woven C/C composites where tensile tests are performed for validation. Stress distribution results indicate that a novel image-based route for FE meshes compared to a unit cell approach gives stronger agreement with experimental data. The image-based approach captures true porosity as fine microstructural details are converted from X-ray tomographic data. In comparison, the unit cell model represents idealizations of composite architecture that ignores porosities.