Accurate measurement of in-plane and out-of-plane shear moduli on 3D woven SiC-SiBC material

The aim of this study is to purpose a robust experimental method to measure both in-plane and out-of-plane shear moduli of a 3D woven Ceramic Matrix Composites (CMC) SiC-SiBC, using torsion tests on rectangular bars. To construct this methodology, several data reduction process have been discussed. Then, the edge effects and their consequences on the shear moduli values have been investigated, using a Finite Element Analysis. Based on the findings of this preliminary study, a robust experimental methodology has been developed. Its originality stems on the use of 3D Digital Image Correlation (DIC) to measure properly twist angle on a restricted area, where the edge effects have lower influence. This methodology has been first validated by proceeding torsion tests on Aluminum bars with well known isotropic properties. Then, the experimental method has been extended to a 3D woven CMC SiC-SiBC material, to measure both its in-plane and out-of-plane shear moduli.