FAILURE PROGRESS OF STITCHED REINFORCED POLYESTER-GLASS LAMINATE AT STATIC BENDING

摘要

The course of failure of polyester-glass fabric laminates,classic(non-stitched)and stitched ones(Fig.1,2),has been studied at three-point static bending tests of the samples.The failure progress was recorded using photographic(Fig.3-5)and acoustic emission(Fig.6-9)methods.It was found that failure process initiation in stitched or non-stitched laminates run by delamination.Delamination in stitched laminates is clearly limited by stitches as the forces causing tangential or translaminar stresses are carried by the stitches to reinforcement layers in a laminate.So the stitched laminate shows milder failure progress than the classic one.At the moment of reaching the maximal stress a dominant failure mechanism in non-stitched composite is delaminating cracking of a matrix while in stitched laminate-cracking of reinforcing fibers.In the latter the higher number of elementary cracks of both components was observed than in classic one,what probably resulted from the higher number of structural defects.