Acoustic Beams Used to Probe Solids for Defects

本研究探讨了声学无损检测方法中波传播效应的基本现象，确定了高斯光束在弯曲流固界面上的传播行为，评估了传感器附近和远离传感器区域产生的波场，并建立了与聚焦光束的非线性相互作用。这项研究的结果将提高对波遇到流固界面时发生的复杂相互作用的理解。如果要检测表面缺陷，瑞利波在表面上的发展是一个重要的事件，这种波在一定的撞击角度下可能会发展。如果要检查内部缺陷，必须避免瑞利波的发展，因为它们从用于探测试样内部区域的光束的能量中减损。声束法是一种有效的非破坏性技术，用于确定表面和内部缺陷的大小和形状。

This research investigates the fundamental phenomena of wave propagation effects for acoustical non-destructive testing methods and determines the behavior of a Gaussian beam propagating across a curved fluid solid interface, evaluates the wave field produced near the transducer and in regions far from the transducer, and establishes the non-linear interaction with focused beams. The results of this research will improve the understanding of the complex interaction occurring as the waves encounter the fluid-solid interface. The development of a Rayleigh wave on the surface which may develop for certain impingement angles is an important event, if surface flaws are to be detected. If interior flaws are to be examined, the development of Rayleigh waves must be avoided because they detract from the energy of the beam used to probe interior regions of the specimen. The acoustic beam method is an effective non-destructive technique for defining the size and shape of both surface and internal flaws.