复合结构界面粘接质量的非线性超声检测

为满足评价复合结构界面粘接质量的需求，研究了一种测量粘接界面粘接强度的非线性超声检测系统。实验中制作了3组有机玻璃/粘接剂/钢结构的粘接试件，粘接剂采用环氧树脂胶粘剂，以3种配比模拟不同的粘接强度。针对目前兰姆波检测方法中其模式的选择相对复杂，脉冲反射回波法未能根据二次谐波激发效率判断粘接状态的问题，提出了一种单频率大幅度超声激励作用下，表征界面超声非线性程度的二次谐波幅值A₂与反射基波幅值A₂₁之比A₂/A₂₁的方法。实验结果表明：非线性效应程度越大，界面粘接质量越差，可将非线性效应程度作为有效评价复合结构粘接质量的特征参数。 为满足评价复合结构界面粘接质量的需求，研究了一种测量粘接界面粘接强度的非线性超声检测系统。实验中制作了3组有机玻璃/粘接剂/钢结构的粘接试件，粘接剂采用环氧树脂胶粘剂，以3种配比模拟不同的粘接强度。针对目前兰姆波检测方法中其模式的选择相对复杂，脉冲反射回波法未能根据二次谐波激发效率判断粘接状态的问题，提出了一种单频率大幅度超声激励作用下，表征界面超声非线性程度的二次谐波幅值A₂与反射基波幅值A₂₁之比A₂/A₂₁的方法。实验结果表明：非线性效应程度越大，界面粘接质量越差，可将非线性效应程度作为有效评价复合结构粘接质量的特征参数。

Measurement of Interface Bond Quality of Composite Structure Using Nonlinear Ultrasound

A nonlinear ultrasonic test system is established to meet the needs of evaluating the interface bond quality of composite structure. Epoxy resin is chosen as adhesive to make three sets of specimens which are made up of synthetic glass/adhesive/steel so as to simulate the different bond strengths with three different rations of epoxy resin to curing agent. For the problem of the complexity to determine the mode of lamb using lamb wave approach and the situation of that bond states cant not be evaluated based on second harmonic exciting efficiency using pulse-echo ultrasonic techniques, a method is developed, in which the specimen is excited by a single-frequency ultrasound, and A₂/A₂₁ (the ratio of second harmonic A₂ to fundamental wave A₂₁) is used to characterize the degree of nonlinear ultrasonic response. The experimental results indicate that the interface bond quality reduces with the increase in the degree of nonlinearity, and thus it can effectively evaluate the interface bond quality.