粘接界面的非线性弹簧模型及实验验证

研究了纵波及横波垂直入射时在粘接界面处的非线性边界条件。在二阶微扰近似及粘接界面层厚度远小于入射声波长的条件下,给出了严格的界面非线性弹簧模型的表达式。数值计算结果表明,利用该模型得到的透射二次谐波与利用连续性边界条件得到的精确解吻合良好。针对钢(铝)的楔形粘接结构,在纵波垂直入射的条件下对该非线性弹簧模型进行了实验验证。实际测量结果显示该模型具有较高的精度;且被粘物与胶层的阻抗比越大,该模型的误差越小。 

Theoretical and experimental research on nonlinear spring models of a bonding interface

The nonlinear boundary conditions on a bonding interface between two solids of a longitudinal or shear horizontal wave under normal incidence are explored.By applying the second-order perturbation method,the nonlinear spring models are rigorously developed in the limit of small thickness to wavelength ratio.Numerical results agree well with the exact solutions obtained by continuous boundary conditions.The nonlinear spring model for longitudinal wave is verified by measuring the nonlinearity of a wedge-shaped bonding structure of steel or aluminum.Experimental results reveal that the above model is rather accurate and as the impedance ratio of adherend to adherend increases,the model becomes more accurate.