Ti-AFRP胶接接头失效过程实验和仿真分析

Experimental and Simulation Analysis of Ti-AFRP Adhesive Joint Failure Process

制备搭接长度为60 mm的钛合金-芳纶纤维编织复合材料单搭接接头,利用DIC、万能试验机等对接头极限载荷与拉伸应变进行表征,同时采用VUMAT子程序模拟芳纶纤维编织布层内损伤和演化,使用Cohesive Zone Model模拟胶层和层间失效。将试验和仿真方法相结合,研究钛合金和芳纶纤维编织复合材料胶接接头表面和内部应变规律,了解异制材料接头失效过程及特征。结果表明,钛合金和芳纶纤维编织复合材料接头失效首先发生在刚度较小的复合材料端头;由DIC和仿真应变云图可知,复合材料的端头出现高应变区,随着时间延长,高应变区域逐渐向钛合金端头扩展,直到接头突然断裂;接头失效部位的两侧为剪切应力导致的失效,中间区域为剥离应力导致的失效。

Single lap joints of titanium alloy and aramid fiber composite with overlap length of 60 mm were prepared,and the ultimate load and tensile strain of joints were characterized by universal testing machine and DIC.At the same time,based on the VUMAT subroutine,the damage and evolution of aramid fiber fabric layers were simulated.The Cohesive Zone Model was used to simulate the adhesive and delamination failure,test and simulation methods were combined to explore the bonding of titanium alloy and aramid fiber woven composite materials surface and internal strain laws reveal,the failure process and characteristics of dissimilar material joints.It was showed that results showed that the failure of bonded joints of titanium alloy and aramid fiber composite firstly occurs at the end of composite adherend with less stiffness.When the load increases,the failure begins to expand from the end of the composite,and the joints appear mixed failure mode.DIC and simulated strain cloud diagrams showed that the composite material tip had a high strain region,and the high strain region gradually increases with time.Extend to the end of the titanium alloy until the joint suddenly breaks;the load transfer of the single lap joint was not collinear,resulting in failure of the left and right sides of the adhesive layer in the high strain area due to shear stress and failure due to peeling stress in the middle.