Mechanical Characterisation and Comparison of T-shape Intersections Made of C/SiC Composites
ABOUAB N. 1, CATY O. 1, EBEL A. 1, GUILLET F. 2, ROGER J. 1
1 Thermo-Structural Composite Laboratory (LCTS) - UMR 5801 (CNRS - CEA - Safran - Bordeaux University), Pessac, France; 2 CEA - Military Application Division, Le Ripault, Monts, France
Ceramic matrix composites (CMC) made of silicon carbide such as Cf/SiC have been developed for aeronautic applications with severe thermomechanical constraints. These materials provide high stiffness and mechanical strengths, important thermal resistance as well as low specific masses. Complex shape like sandwich structures can even further increase the flexural stiffness and lightness of the composites. However, complex shape parts made out of long-fibre composites are difficult to manufacture with satisfactory properties. Cf/SiC T-shape intersections have therefore been produced and characterised here as representative elements of a sandwich structure.
Studies on T-shape structures in carbon fibre reinforced polymer have already demonstrated the structural weakness of preform assemblies with poor inter-laminate bounding. Various reinforcements were then tested and compared in term of tensile strengths [1–3]. Nevertheless, to the best of our knowledge no such characterisation has been performed on CMC T-shape samples.
Various Cf/SiC T-shape samples were then manufactured: 2D preforms co-densified by CVI with or without inter-laminate reinforcements, and 3D woven T-shape intersections. Each sample were characterised mechanically by tensile testing and morphologically by X-ray tomography. The measured properties will be discussed and compared in regard to the various morphologies. Furthermore, the specific assembly designed to perform the mechanical testing of T-shape samples will be presented.
References:
[1] Yan S, Zeng X, Long A. Experimental assessment of the mechanical behaviour of 3D woven composite T-joints. Compos Part B Eng 2018;154:108–13. https://doi.org/10.1016/j.compositesb.2018.08.007.
[2] Cartié DDR, Dell’Anno G, Poulin E, Partridge IK. 3D reinforcement of stiffener-to-skin T-joints by Z-pinning and tufting. Eng Fract Mech 2006;73:2532–40. https://doi.org/10.1016/j.engfracmech.2006.06.012.
[3] Bigaud J, Aboura Z, Martins AT, Verger S. Analysis of the mechanical behavior of composite T-joints reinforced by one side stitching. Compos Struct 2018;184:249–55. https://doi.org/10.1016/j.compstruct.2017.06.041.
