The Energy Release Rate at Knik and Peak Points for Polyester-kevlar fiber and polyester-Polyethylene fiber

Abstract

A single fiber drag-out test was used in this study to measure the critical energyrelease rate of a crack at interface of composite ,using Nairn model at the initiationof crack (knik point) or the beginning of the difference in elastic behavior betweenfiber and matrix and the critical energy release rate when the crack length equalembedded length (peak point ) or full debond , the difference between these pointseffected by the strength of adhesion between the fiber and the matrix and also bythe wettability or diffusion of polyester monomer into interfibrillar space wherepolyethylene is solid fiber while kevlar is rope fiber .