激光超声技术能够在材料表面形成超声波, 是实现材料缺陷无损检测的重要环节。借助Abaqus有限元分析工具, 基于激光超声热弹机制建立了轴对称铝板的表面缺陷模型, 模拟了激光激发产生的表面波在材料中的传播特性及其与铝板缺陷的相互作用过程。数值模拟实验表明, 铝板表面缺陷的分布深度值越大, 反射波越强, 并且当缺陷深度达到一定程度时, 反射波的幅值趋于稳定; 但缺陷的分布宽度对于反射波的影响则十分有限。所得结论为基于激光超声的材料缺陷的定量检测及识别提供有效的理论依据。

It is able to generate the ultrasonic waves on the surface of materials based on the laser-generated ultrasonic technology which is an important part of non-destructive testing for material defects. With the finite element analysis software of Abaqus, the defect model of the symmetric aluminum to be measured was established based on the laser ultrasonic thermo-elastic mechanism. Besides, the propagation characteristics of the laser-induced surface wave in the material and the interaction process between the laser-induced surface wave and the defects were simulated. Through the numerical simulation and theoretical analysis, the results show that the amplitude of the reflected wave increases with the depth of the defect and reaches steady state when the depth of the defect is up to a certain value. Instead, the width of the defect has a limited effect on the reflected wave. All of these conclusions can promote the development of the laser-generated ultrasonic technology for the detection and identification of the material defects.