Quantitative thermomechanical characterisation of 3D-woven SiC/SiC composites from in-situ tomographic and thermographic imaging

3D woven composites are often modelled using homogenisation whose foundation requires the validity of scale separation — microstructure scale much smaller than any other scales from part geometry, manufacture or loading — often violated in reality. Modelling has then to be confronted with experimental data representative of actual service conditions. A high-temperature multiaxial thermomechanical test is carried out on an L-shaped specimen. It is followed by synchrotron X-ray tomography and infrared thermography. The coupling of the complex geometry and weaving pattern, and a non-homogeneous thermal field, induces a very irregular stress field inside the sample, generating locally unusual loading configurations. Integrated digital volume correlation provides a fine identification of the material parameters of an image-based mesoscale model. Most involved parameters are identified with good precision, including tow shear moduli. The model is able to describe the sample deformation in the elastic domain accurately.