冲击载荷下CFRP及GFRP层板断裂韧性的研究

利用Hopkinson杆加载装置, 对带有单边切口的炭纤维增强复合材料(CFRP)及玻璃纤维增强复合材料(GFRP)层板试件进行冲击拉伸加载实验。根据一维应力波理论求得作用于试件上的载荷P(t)和试件加载点的位移δ(t)。 根据试样中应力随时间的变化历史σ(t), 并基于断裂韧性测试原理, 建立了动态应力强度因子K_Ⅰ (t)响应曲线。利用柔度变化率方法确定起裂时间, 分别得到在两种加载速率下CFRP、 GFRP层板的动态断裂韧性。结果表明, 随着加载速率的提高, 这两种复合材料的断裂韧性降低。

Fracture toughness research of CFRP and GFRP laminates under impact load

The CFRP and GFRP laminates with a crack on a single side are loaded under tensile impact by the apparatus of Hopkinson bar.The curves of the load P(t) loaded on the specimens and the displacement δ(t) of the specimens were acquired according to the one-dimensional stress wave theory. The curves of dynamic stress intensity factor KⅠ (t) were set up according to the fracture toughness measuring theory and the stress changing σ(t) with time in the specimens. With the compliance changing rate method, the crack initiation time and the dynamic fracture toughness of CFRP and GFRP laminates were obtained at two kinds of strain rates separately. The experiment results show that the fracture toughness of CFRP and GFRP laminates increased with loading rates increasing.