不锈钢增材制造件表面缺陷激光超声检测

Laser ultrasonic detection for surface defect of stainless steel additive manufacturing parts

利用激光超声技术检测增材制造件表面缺陷,采用有限元方法模拟热弹机制下激光激发超声波的传播过程,对不同探测位置接收的表面波反射信号进行了分析,研究缺陷的深度和宽度对表面波反射信号的影响。对316L不锈钢增材制造件进行了激光超声检测试验,验证了该模型的正确性。利用小波软阈值去噪算法处理采集到的激光超声信号。结果表明,数值模拟与试验结果基本一致,表面波与缺陷作用产生的RS波和RR波的到达时间差可以检测缺陷的深度,缺陷的宽度对检测结果几乎无影响。

Laser ultrasonic technology was used to detect surface defects of the additive manufactured parts, and the finite element method was used to simulate the propagation process of laser-excited ultrasonic waves under the thermoelastic mechanism. The surface wave reflection signals received from different detection positions were analyzed, and the influence of the depth and width of defects on the surface wave reflection signal was studied. Laser ultrasonic testing experiments on 316 L stainless steel additive manufacturing parts verified the correctness of the model, and then the wavelet soft threshold denoising algorithm was used to process the collected laser ultrasound signal. The results showed that the numerical simulation was basically consistent with the experimental results. The arrival time difference of the RS wave and the RR wave generated by the surface wave and the defect could detect the depth of defects, and the width of defects had almost no effect on the detection result.