奇异性法预测粘接厚度对单搭粘接接头失效的影响

A Stress Singularity Approach to Predict Initiate Failure of Single Lap Joints with Varying Bondline Thickness

通过应力奇异性模型预测了铝5052-铝5052单搭粘接接头初始失效位置的受力情况.与Bogy理论公式相比,应力奇异性有限元模型不但可以很好的确定奇异应力场的形状(应力奇异性指数),且还可以确定奇异应力场的大小(应力强度因子),实现了对单搭粘接接头强度的准确分析和预测.研究结果表明:粘接剂厚度的变化不会影响奇异点应力奇异性指数,但会影响该处应力强度因子,应力强度因子随着粘接剂厚度的增加而增大,应力强度因子越大,粘接界面强度越低,该变化趋势与试验结果相吻合.

A stress singularity model was used to predict that failure of single lap-shear bonded joint with various bondline thickness. It not only described the shape of the stress field around singularity and but also described the magnitude of the stress field. The stress singularity factor at the theoretical point of maximum stress in an uncracked single lap joint was analyzed by the finite element method （FEM）. By comparing the determination of strength of the singularity by finite element analyzed with analytical prediction of Bogy function with various adhesive thicknesses, good agreement was shown between FEM with Bogy function. The bondline thickness has no impact on the singularity order, and calculated stress intensity factor was found to increase with increasing bondline thickness.