Creep rupture failure of woven composites

This paper presents an experimental investigation of the tensile creep rupt ure behaviour of woven fibre composites stitched with cotton and carbon thr eads along the loading direction. Creep rupture tests were conducted at amb ient temperature and various elevated temperatures. The experimental result s reveal that through-thickness stitching can significantly increase the cr eep rupture life of woven composites, provided the stitches are aligned in the direction of loading. It is shown that the creep rupture lifetime can b e well correlated using the modified Monkman-Grant relationship, with all t he creep rupture data, stitched and unstitched composites, falling in a nar row band. Consequently, for a given creep strain rate the rupture life is i ndependent of the testing temperature and the stitching method. Observation s of the fracture surfaces revealed that stitching has dramatically reduced delamination and enhanced creep rupture life.