Tensile properties and failure mechanisms of 3D woven GRP composites

Tensile tests were performed on glass reinforced polymer (GRP) composites w ith three-dimensional (3D) orthogonal, normal layered interlock, and offset layered interlock woven fibre architectures. The mechanical properties and failure mechanisms under tensile loading were similar for the three compos ites. Cracks formed at low strains within the resin-rich channels between t he fibre tows and around the through-thickness binder yams in the composite s, although this damage did not alter the tensile properties. At higher app lied tensile stresses the elastic modulus was reduced by 20-30% due to inel astic tow straightening and cracking around the most heavily crimped in-pla ne tows. Further softening occurred at higher strains by inelastic straight ening of all the tows. Composite failure occurred within a localised region and the discrete tow rupture events that have caused tow lock-up acid pull out mechanisms in other 3D woven composites were not observed. Crown copyri ght (C) 1999 Published by Elsevier Science Ltd. All rights reserved.