环形光源激发超声进行缺陷检测的数值研究

为了提高激光超声的激发效率且不对被测表面造成损伤,改变了光源的空间分布,采用脉冲激光环形光源激发超声及有限元方法,应用多物理场耦合软件,对铝板中激发的超声全场波形进行了数值模拟,研究了环形光源中轴线上叠加横波的激发特性随激光参量而变化的规律,并与点光源激发超声进行对比.通过模拟缺陷所导致超声场的变化规律,提出一种环光源...

Numerical study on defect detection by ring light source generated ultrasonic

In order to improve the generation efficiency of laser ultrasonic without damaging the measured surface, the spatial distribution of the laser source was changed, and the pulsed ring laser source was used. Using the finite element method, the numerical simulation of the full field ultrasonic wave generated in the aluminum plate was carried out by COMSOL Multiphysics. The generation characteristics of the superposition shear wave on the central axis of the ring laser source were studied, which vary with laser parameters. By simulating the change law of the ultrasonic field caused by defects, a method of detecting cracks on both sides of the ring laser source was proposed. The feasibility and effectiveness of defect detection by superposition shear wave were verified by simulating the change rule of ultrasonic field caused by defects. The results show that the generation efficiency can be significantly improved by using the ring laser source because ring light source loss is usually less than 50%. The direction of shear wave propagation is stable. The superposition depth of the shear wave is related to the ring radius, and the ring half-width can affect the intensity of the wave. The results provide a reference for the application of ring laser source generated ultrasonic in defect detection.