Fatigue and Post-Fatigue tensile behaviour of Non-Crimp stitched and unstitched Carbon/Epoxy composites

Valter Carvelli (1) , Vanni Neri Tomaselli (1) , Stepan V. Lomov (2) , Ignaas Verpoest (2) , Volker Witzel (3) , Bjorn van den Broucke

1 Department of Structural Engineering
2 Department of Metallurgy and Materials Engineering
3 Universität Stuttgart

An experimental study is described in this paper dealing with the tensile-tensile fatigue and the quasi-static post-fatigue tensile behavior of a structurally stitched multi-ply carbon composite and the unstitched counterpart. The influence of the stitching on the fatigue life and on the residual post-fatigue quasi-static properties in two principal direction is investigated. The fatigue behavior of both composites is represented by Wöhler-like diagrams. The damage imparted during fatigue is studied by X-ray analyses. The residual mechanical properties of the fatigued composites after different number of cycles are compared in term of stiffness and strength. The post-fatigue quasi-static tensile tests include acoustic emission (AE) registration and full-field surface strain mapping (SM) to investigate the damage onset and development. The main conclusions of the experimental work are: the fatigue life is improved in the direction of the structural stitching and is reduced in the orthogonal direction; for the considered cyclic stress level the post-fatigue reduction of the mechanical properties is limited by the structural stitching.

Mots clés: (A) Laminate; (B) Fatigue; Mechanical Properties

Domaines: Matériaux

Valter Carvelli, Vanni Neri Tomaselli, Stepan V. Lomov, Ignaas Verpoest, Volker Witzel, et al.. Fatigue and Post-Fatigue tensile behaviour of Non-Crimp stitched and unstitched Carbon/Epoxy composites. Composites Science and Technology, 2010, 70 (15), pp.2216. ⟨10.1016/j.compscitech.2010.09.004⟩. ⟨hal-00690070⟩