A Novel Test Method to Induce Bi-axial Stress States in Thin-ply Carbon Composites Under Combined Longitudinal Tension and Transverse Compression

摘要

A novel test configuration has been developed to induce combined stress-states of inplanelongitudinal tension and transverse compression in unidirectional (UD)composite layers. Two different multi-directional laminates have been designedincorporating UD carbon/epoxy plies embedded in angle-ply blocks of the samematerial. The scissoring deformation of the angle-plies induces compression in thecentral UD layers when the composite is strained in the 0° fibre direction. The amountof transverse compressive stress is determined through an inverse identificationmethod from the measured surface strains of the laminates. Despite the large in-planetransverse compressive strain generated, there is only about 9% drop in the failurestrain of the laminates when compared to the baseline failure strain of the UDcarbon/epoxy material.