非连续阻抗结构超声传播特性分析

Analysis of ultrasonic propagation characteristics of discontinuous impedance structure

超声检测技术在航空航天、生物医学等领域有着广泛的应用,在对复合结构的质量检测等方面也发挥着重要作用。非连续阻抗结构是一种声阻抗不同的复合结构,为研究超声在非连续阻抗结构中的传播特性,设计单层结构和复合结构模型进行超声检测数值模拟,对比分析两种结构中超声波传播规律及波形变化;并探究复合结构中添加的非连续阻抗薄层厚度对超声信号的影响,对薄层由薄到厚变化时超声信号的频率变化进行分析,得出薄层厚度在2~8 mm时激励位置处信号频率明显减小等结论,为实际的复合结构件设计以及超声检测技术提供一定的理论基础。

Ultrasonic detection technology has a wide range of applications in aerospace, biomedicine and other fields, and it also plays an important role in the quality detection of composite structures. The discontinuous impedance structure is a composite structure with different acoustic impedances. In order to study the propagation characteristics of ultrasonic in the discontinuous impedance structure, a single-layer structure and a composite structure model are designed for ultrasonic testing numerical simulation, and compares and analyzes the ultrasonic waves in the two structures propagation law and waveform changes;and explore the influence of the thickness of the discontinuous impedance thin layer added in the composite structure on the ultrasonic signal, analyze the frequency change of the ultrasonic signal when the thin layer changes from thin to thick, and find that the thickness of the thin layer is between 2 mm and 8 mm Conclusions such as the obvious reduction of signal frequency at the time of excitation position. It provides a theoretical basis for the design of composite structure and ultrasonic detection technology.