一种单面评估表面细小凹坑的波型转换新方法

A New Method of Wave Mode Conversion for Tiny Pits Evaluation on Surfaces

提出了一种根据波型转换原理单面评估表面半球形细小凹坑（０．９５～２．５ｍｍ）直径的新方法，用自制的电磁超声换能器测定了纵波（Ｐ波）正入射至多种不同直径的凹坑上后转型横波（ＳＶ波）的标准散射指向图，提出了以４５°和６０°散射方向ＳＶ波的振幅比作为凹坑直径评估的依据，凹坑评估测量值与实际值符合较好．

A new method used to evaluate pits (φ0.95～2.50mm) on surfaces in single side in the light of wave mode conversion is proposed. In the experiments, an electromagneticacoustic transducer manufactured by the authors is used to obtain the amplitude pointing diagrams of the converted SV waves scattered from the pits of different diameters with P wave normal incidence. A suggestion is made that the amplitude ratio of SV waves scattered at 45° direction to that scattered at 60° direction is the basis of evaluating the diameters of pits. The pit diameter is evaluated in practice. The measuring data are in good agreement with the practical data.