Belgroune Djema, de Belleval Jean François, Djelouah Hakim
Laboratoire Roberval, Unité de Recherche en Mécanique, Associée au CNRS, Université de Technologie de Compiègne, BP 20, 259-60205 Cedex, France.
Ultrasonics. 2008 Jul;48(3):220-30. doi: 10.1016/j.ultras.2008.01.003. Epub 2008 Jan 26.
This article develops a model for the study of the transient ultrasonic waves radiated by a transducer in a liquid and transmitted into a solid through a plane interface. The method is an extension to the transient case, of the angular spectrum method previously developed for the monochromatic case. It is based on the decomposition of the ultrasonic field, in impulse plane waves. The radiated waveform is calculated at any point in the field by a simple summation of these impulse plane waves, where the propagation delay and the refraction have been taken into account. These plane waves are, first of all, delayed by an amount of time corresponding to the travel time up to the considered field point. The transmission through the plane interface is taken into account by using Snell refraction laws and transmission coefficients. In the obtained results all the waves previously described by other authors are highlighted: direct wave, edge waves, head waves as well as subsurface waves with a clear resolution between compression and shear waves.
本文建立了一个模型，用于研究换能器在液体中辐射并通过平面界面传输到固体中的瞬态超声波。该方法是对先前为单色情况开发的角谱方法在瞬态情况下的扩展。它基于超声场在脉冲平面波中的分解。通过对这些脉冲平面波进行简单求和，计算出场中任意点的辐射波形，并考虑了传播延迟和折射。这些平面波首先延迟一个与到达所考虑场点的传播时间相对应的时间量。通过使用斯涅尔折射定律和透射系数来考虑通过平面界面的传输。在所得结果中，突出显示了其他作者先前描述的所有波：直达波、边缘波、头波以及表面下波，并且在压缩波和剪切波之间有清晰的分辨。
