Materials Science Forum, Vol.514-516, 624-628, 2006
Residual strength after low velocity impact in carbon-epoxy laminates
The aim of present work is to study the influence of low energy impacts on residual strength of carbon-epoxy laminates. Experimental tests were performed on [0,90,0,90](2s) and [0,90](8) laminates using a drop weight-testing machine. The influence of the laminate stacking sequence is analysed under 1.5 J, 2 J, 2.5 J and 3 J impact energies, corresponding to a 0.91 ms(-1), 1.05 ms(-1). 18 ms(-1) and 1.29 ms(-1) of impact velocity, respectively. The impacted plates were inspected by C-Scan to evaluate the size, shape and position of the delaminations through the thickness of the plate. The same plates were inspected by C-Scan before the impact, to evaluate the eventual presence of defects produced during the manufacturing process. The residual flexural strength showed that the [0,90,0,90](2s) laminates have better performance than the [0,90](8) ones. The explanation is related with the lower flexural stiffness of the antisymmetric lay-up relatively to the symmetric one.