各向同性薄板中横穿孔缺陷的超声兰姆波层析成像  

Ultrasonic Lamb wave tomography of through hole flaws in isotropic thin plates

作　　者：张海燕[1] 周全[1] 吕东辉[1] 刘镇清[2] 

机构地区：[1]上海大学通信与信息工程学院,上海200072 [2]同济大学声学所,上海200092

出　　处：《声学学报》2007年第1期83-90,共8页Acta Acustica

基　　金：国家自然科学基金资助项目(10504020)

摘　　要：本文将地球物理中的跨孔层析重建技术用于兰姆波的定量无损评价。综合射线追踪与代数重建技术(ART),发展了横穿孔缺陷的超声兰姆波层析成像方法。基于Snell定律和费马原理,采用射线追踪方法寻求发射和接收换能器之间超声兰姆波的实际传播路径并计算走时,然后采用ART算法对走时数据进行速度图像重建。给出了具有人工横穿孔缺陷铝板的数值模拟和实验数据的直射线和弯曲射线重建图像。结果表明,弯曲射线ART方法比直射线ART方法重建的缺陷尺寸更接近于缺陷的真实尺寸,并且当考虑射线弯曲时,重建图像的赝象也有所降低。A “cross borehole” tomographic reconstruction technique exploited by seismologists is used for quantitative Lamb wave nondestructive evaluation （NDE） in this paper. Combining ray tracing with algebraic reconstruction technique （ART）, ultrasonic Lamb wave tomography for through hole flaws is developed. Based on Snell law and Fermat＇s principle, ray tracing is used to find actual ray paths and calculate travel times of ultrasonic Lamb waves between transmitting and receiving transducers. ART is then carried out to realize the velocity imaging reconstruction for the given set of arrival times. Reconstruction for both simulated and experimental data acquired on aluminum plates with machined through hole flaws is presented with straight-ray and curved-ray. The results demonstrate that the sizes of flaws reconstructed with curved-ray ART appear to be closer to their real size than straight ray ART, and the artifacts of reconstructed images are also reduced when ray-bending is considered.

关 键 词：超声兰姆波 缺陷尺寸 层析成像 穿孔 各向同性 射线追踪方法 代数重建技术 ART算法 

分 类 号：O422[理学—声学]