预紧力对复合材料单搭接接头拉伸性能的影响

Effect of Preload on Tensile Properties of Composite Single-lap Joints

为研究螺栓预紧力对复合材料单搭接接头拉伸性能的影响,依据ASTM标准设计拉伸试样,对试样进行拉伸试验,试验中采用3D-DIC技术测量复合材料板表面应变。研究了不同预紧力对接头载荷-位移曲线、极限载荷、拉伸刚度、破坏位移和表面应变等的影响。结果表明:预紧力大小不会改变载荷-位移曲线的变化趋势和接头失效形式。随着预紧力增大,接头极限载荷和破坏位移先增大后减小;拉伸刚度逐渐增大;复合材料板表面e_(yy)应变绝对值减小,应变集中状况得到改善。

To study the effect of bolt preload on the tensile properties of composite single-lap joints,tensile specimens are designed according to ASTM standard,and tensile experiments are conducted on the specimens,in which the 3D-DIC technique is used to measure the surface strain of composite laminates in the experiments.The effect of different preloads on the load-displacement curve,ultimate load,tensile stiffness,damage displacement and surface strain of the joints is studied.The results show that the preload force does not change the trend of load-displacement curve and joint failure form.As the preload force increases,the ultimate load and damage displacement of the joint increase first and decrease afterwards,the tensile stiffness gradually increases and the absolute value of e_(yy)strain on the surface of the composite laminates decrease.Thus the strain concentration is improved.