复杂结构焊缝的非线性超声检测方法

Nonlinear ultrasonic method for detecting weld of complicated structure

振动声调制技术是一种新出现非线性超声无损检测方法.文中简要介绍了此技术的检测原理,并对其在复杂结构焊缝质量检测中的应用进行了初步研究.制作了小径管座角焊缝试样,分别在单频激励和扫频激励条件下进行检测.结果表明,缺陷试样的调制强度均高于参考试样,且在特定高频频率范围内,二者差别显著,更有利于焊缝质量判别.而采用扫频技术可快速得到合适的高频频率范围,提高检测效率.与超声C扫描检测结果相比,采用振动声调制技术对小径管座角焊缝进行检测是可行的,但缺陷的定位定量分析等问题还需要进一步研究.

Vibro-acoustic modulation technique( VAM)is a novel nonlinear ultrasonic method. The principle of VAM was briefly introduced,and then VAM with sine wave excitation and swept probing excitation was utilized to detect the fillet weld of small diameter nozzle stubs sample. It was found that the modulation intensity of defect sample was larger than reference sample,this difference would be much larger in some special high frequency range,which would be more beneficial to distinguish the weld quality. And the proper high frequency range can be quickly obtained by the swept probing excitation technique.Compared with the ultrasonic C-scan results,it was indicated that the VAM technique can be used to evaluate the quality of the fillet weld,however,further work is required to locate and quantitatively detect the damage.