含孔隙CFRP层合板冲击损伤试验

Experiments of impact damage of CFRP laminates with voids

为了研究孔隙率及冲击能量对CFRP层合板冲击损伤容限性能的影响规律,对3种孔隙率的CFRP层合板试样分别进行3、6、9、12、15 J五种能量的冲击作用.采用超声C扫描、金相显微镜、热揭层及目视等方法对CFRP层合板试样的冲击损伤进行检测.试验结果表明:相同冲击能量作用下,孔隙率对凹坑深度及损伤投影面积均存在不利影响;冲击能量超过9 J后,随着冲击能量增加,凹坑深度快速增长,但是分层面积增长缓慢.热揭层试验揭示了CFRP层合板冲击性能在冲击能量9 J前后发生突变的破坏机理,即当冲击能量超过9 J后,冲击能量由基体和纤维共同消耗转移为主要由纤维抵抗冲击能量.

Impact tests on CFRP laminates with three porosity levels were conducted at impact energy levels of 3, 6, 9, 12 and 15 J to study the influences of porosity and impact energy on the impact damage tolerance. The impact damage was evaluated by ultrasonic C-scan measurement, metallurgical microscope, thermal deply technique and visual inspections. The experimental results show that the porosity has detrimental effects on the dent depth and the damage area of composite laminates for the same impact energy. The dent depth increases rapidly with the increasing of impact energy, and a progressive increase of the impact area occurs after 9 J. The thermal deply test reveals the failure mechanism of impact damage mutation of CFRP laminates when the impact energy exceeds the threshold 9 J. The impact energy is consumed from the matrix cracks and delaminating to the fiber cracks after 9 J.