Predicting the mechanical behaviour of carbon fibre reinforced silicon carbide with interlaminar manufacturing defects

DLR, German Aerospace Centre, Institute of Structures and Design, Stuttgart, Germany

^a Corresponding author: Severin.Hofmann@dlr.de

Abstract

A finite element approach based on experimental material data is presented in order to compute the mechanical reliability of carbon fibre reinforced silicon carbide, C/C-SiC, taking interlaminar manufacturing defects into account. The approach is evaluated on sample scale by modelling the flexural behaviour of C/C-SiC samples containing delaminations after liquid silicon infiltration (LSI) processing. The non-destructive evaluation methods, determination of fracture mechanical input data and the numerical cohesive zone approach are described. The numerical predictions of flexural stiffness and strength of samples with and without interlaminar defects were validated by bending tests of the respective samples. The difference between tensile and bending behaviour is explained by FE modelling for this group of CMC materials.