Author(s)

J.J. Horst

Abstract

A fatigue mechanism of bridged cracks is proposed, based on some novel experimental techniques: Measurements of creep during fatigue, through thickness strength profiles of specimens that had been subjected to a fixed number of fatigue cycles. SEM fractography was used in the normal way on broken specimens, but also on specimens that were fatigued, but not up to failure, and consequently cryogenically broken. Damage starts with void initiation at fibre ends, the voids consequently grow along the fibre and merge into larger "cracks". For this growth process especially the tensile strength of the fibre - matrix interface is important. However not one complete crack exists, as the crack walls remain connected at a number of spots. Damage is not hom

Keywords