温度-荷载耦合作用下玻璃纤维增强复合材料-泡沫夹层结构Ⅰ-Ⅱ混合型界面断裂试验

Experiments on mixing Ⅰ-Ⅱ interfacial fracture toughness of glass fiber reinforced plastic-foam sandwich structure under coupling effects of high temperature and loading

复合材料夹层结构在长期的使用过程中发现界面剥离是夹层结构失效的常见模式之一,因此十分有必要研究不同温度条件下,玻璃纤维增强复合材料(GFRP)-聚氨酯泡沫夹层结构的I-II混合型界面断裂韧性。本项研究采用单臂弯曲试验(SLB)的方法测量GFRP-聚氨酯泡沫夹层结构的荷载-挠度曲线和裂纹扩展长度。试验结果表明:随着温度的升高,裂纹沿着界面扩展,芯材无破坏现象,极限承载力呈下降趋势。通过计算应变能释放率发现,随着温度的升高应变能释放率峰值呈上升趋势。运用界面裂纹扩展准则判定裂纹扩展符合理论要求。

Composite material sandwich structure was widely used in many engineering fields due to its excellent performance. It is found that interfacial peeling is one of the common patterns of sandwich structure failure in the long-term use. The mixing Ⅰ-Ⅱ interfacial fracture toughness of glass fiber reinforced plastic( GFRP)-polyurethane foam sandwich structure under the effect of different temperatures was considered. The load-displacement curve and length of crack propagation of GFRP-foam sandwich structure were measured by single leg bending test(SLB). Results showed that as the temperature increased,the crack was expanded along the interface,the core material had no damage,and the ultimate bearing capacity was decreased.It was found that the peak of strain energy release rate was on the upward trend with the increase of temperature.The application of interface crack extension criterion to determine the crack propagation met the theoretical requirement.