Tension-Tension Fatigue Strength Characteristics of Hybrid Composites with Non-Woven Tissue.

Abstract

Fatigue behavior characteristics of hybrid composites with non-woven carbon tissue are inves-tigated under tension-tension fatigue loadings. Hybrid laminates are made by interleaving non-woven carbon tissue between CFRP-prepreg layers. Ten kinds of laminates are studied; namely, non-woven carbon tissue laminates, transverse [90]12, off-axis [45]12 and angle-ply [±45]3S CFRP laminates, and transverse ([90//90//90//90//90//90/]S, [//90//90//90//90//90/]S), off-axis ([45//45//45//45//45//45/]S, [//45//45//45//45//45//45/]S) and angle-ply ([+45//-45// +45//-45// +45//-45]S, [//+45//-45//+45//-45//+45//-45]S) hybrid laminates. The symbol // means that the non-woven carbon tissue layer is located between the CFRP-prepreg layers, and the symbol / means a half of non-woven carbon tissue layer thickness. The effects of non-woven carbon tissue on the tension-tension fatigue life of all hybrid specimens, and moreover the residual strength and stiffness of angle-ply hybrid specimens are evaluated. The fatigue damage and failure mechanisms of the hybrid composites are discussed through observation results with an optical microscope. The hybrid composite laminates seem to be effective to improve the fatigue characteristics.