焊缝特征导波模态的分析与应用

为满足焊缝快速高效无损检测需要,并提高超声导波对焊缝缺陷的灵敏度,研究高频下的焊缝导波模态尤为重要。基于COMSOL软件建立了二维对接焊缝半解析有限元模型,通过数值模拟与分析发现,频率大于300 kHz时焊缝中SH_(w1)模态几乎无频散、泄露小,适合于长距离快速焊缝检测。通过试验验证了SH_(w1)模态导波在对接焊缝中的传播特性,确定了最佳激励频率范围为320~360 kHz;并对焊缝中直径为3 mm的预置孔洞缺陷实现了检测,定位精度高于2.5%。

Analysis and Application of Weld Feature-guided Waves Mode

In order to realize the fast and efficient detection of weld and improve the sensitivity of ultrasonic guided wave to weld defects, guided wave modes under high frequency have been researched. A two-dimensional semi-analytical finite element model of butt weld was established based on COMSOL. A non-leaky and almost non-dispersive mode was found through numerical simulation at the frequency over 300 kHz. This mode, named SHw1 mode in the weld, is very attractive for weld inspection. The characteristics of SHw1 mode propagating in butt weld were confirmed by experiments, and the best excitation frequency range from 320 kHz to 360 kHz was also defined. The defect which is a hole with 3 mm in diameter in weld was recognized successfully and the location accuracy is more than 2.5%.