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.

Automated summary

3D woven composites are often modelled using homogenisation, but this approach is often not valid in reality due to violations of scale separation. To overcome this, experimental data representative of actual service conditions needs to be incorporated. A high-temperature multiaxial thermomechanical test, synchrotron X-ray tomography, and infrared thermography were used to investigate the behavior of an L-shaped specimen. The results provided valuable insights into the complex stress and deformation patterns within the sample.