钛合金-芳纶纤维复合材料单搭接接头的失效形式

Failure Modes of Titanium Alloy-Aramid Fiber Composites Single Lap Joints

采用钛合金与芳纶纤维复合材料制备同质与异质材料单搭接胶接接头。利用数字图像相关技术、万能试验机、光学显微镜等手段,对拉伸载荷下的接头应变、极限载荷与破坏模式进行表征,分析不同搭接材料接头应变场及胶接性能,研究了钛合金-芳纶纤维复合材料接头失效形式。结果表明,在拉伸载荷下,钛合金-芳纶纤维复合材料接头复合材料应变远大于钛合金应变,搭接区域外部应变大于搭接区域内应变;接头偏移及被胶接件变形高于钛合金或芳纶纤维复合材料同质接头,承载能力较低;搭接区域复合材料端头剥离及剪切应力集中,是接头的薄弱部位,易出现渐进失效;破坏模式主要为复合材料层间破坏与钛合金-胶层界面破坏,芳纶纤维丝束承受剥离或剪切力断裂。

Single lap joints with different adherends were prepared by using titanium alloy and aramid fiber composites.The joints strain,ultimate load and failure mode under tensile load were characterized by digital image correlation,universal testing machine and optical microscope.The strain field and bonding performance of joints with different adherends were analyzed to study the titanium alloy-aramid fiber composite single lap joint failure mode.The results show that with the tensile load,to titanium alloy-aramid fiber composites single lap joints,the strain of composite adherends is much larger than that of titanium alloy,and the external strain of bonding area is larger than that in the bonding area;the joint offset and deformation of adherends is higher than those of titanium alloy and aramid fiber composite joints,and the bonding performance is low;the joint stripping and shear stress concentration of composites in the bonding area is a weak part,and the progressive failure occurs from here;the failure mode is mainly the delamination of composites and the interfacial failure between the titanium alloy and adhesive,and the fracture of aramid fiber tow is subjected to peeling or shearing force.