多层黏接结构的阵列超声检测评价方法

Ultrasonic array testing and evaluation method of multilayer bonded structures

在金属与橡胶等非金属材料的多层黏接结构的超声检测中,介质间声阻抗差异和超声衰减显著,致使脱黏缺陷检测信噪比低,缺陷识别困难。为了提高多层黏接结构中脱黏缺陷的检出能力,提出了基于线性阵列超声换能器的超声检测评价方法。分析了声波在黏接界面的传播特性,得出声波在多介质层系的反射系数频谱关系;基于多层黏接结构的三维CAD检测模型,建立多层结构的阵列超声声束路径通用计算方法,依据多层介质的刚度矩阵传递模型,构建数值仿真分析模型,实现阵列超声聚焦方案和检测工艺的设计;分析了不同黏接状态下界面回波信号的幅度谱,提出采用幅度谱特征进行C扫描成像的方法。实验结果表明:所提阵列超声检测评价方法可有效提升多层黏接结构的检测效率,提高检测信噪比,降低脱黏缺陷C扫描成像表征的复杂度。

In the ultrasonic detection for multi-layer bonding structures of metal and non-metal materials such as rubber,the signal to noise ratio of debonding defect is low,and the defect identification is difficult,due to the significant difference in acoustic impedance between media and large ultrasonic attenuation.In order to improve the detection ability of de-bonding defects in multilayer structures,a novel ultrasonic detection and evaluation method based on linear array ultrasonic transducers is proposed.Firstly,the propagation characteristics of ultrasonic waves at the bonding interface are analyzed,and the spectral relationship of the reflection coefficient in a multilayer system is described.Further,a numerical simulation analysis model is built in accordance with the stiffness matrix transfer model of multilayer medium,which is used to realize the design and calculation of the ultrasonic array focusing scheme and detection process.These methods are based on the 3D CAD inspection model.Finally,by analyzing the amplitude spectrum characteristics of interface echo signals under different bonding states,a C-scan imaging method using amplitude spectrum characteristics is proposed.The experiment results show that the method proposed can effectively improve the detection efficiency of multilayer bonded structures and improve the signal-to-noise ratio of detection results,and reduce the complexity of C-scan imaging characterization of de-bonding defects.