Measurement of hole damage characteristics in the glass fibre reinforced plastic composite using digital image correlation technique

Characterization of the strain behaviour around the matrix and fibre holes in unidirectional glas fibre reinforced plastic composite laminates was carried out. The longitudinal and transverse strain fields around holes machined in tensile laminate specimen were determined by measurement of full-field strain distributions during tensile loads using the digital image correlation (DIC) technique. From these measurements, the strain concentration around the holes and strain gradient along the hole section were quantitatively determined and the strain fields during the failure evolvement process could be characterized. It was revealed that the longitudinal strain concentration of the matrix hole was relatively greater than that of the fiber hole, while the compressive transverse strain near the fiber hole was slightly larger than that near the matrix hole. Furthermore, it was found that the normalized peak strains, epsilon(yy) / epsilon(infinity), for both matrix and fiber holes were increased with increasing applied stress and that the strain for the fiber hole was slightly lower than that for the matrix hole. The subsequent failure processes for glas fibre reinforced plastic composite (GFRP) UD (uni-directional) composite specimen with a hole could be visualized and monitored by acquiring digital image correlation images.