超声瑞利波测试材料表面载荷应力的实验研究

实验研究了利用超声瑞利波传播特性测试材料表面应力的方法.在测试过程中采用回振法测声速,以分辨应力作用引起声速的徽小变化;并设计夹具实现探头与试样之间的稳定耦合和弹性接触,精简了实验机构,提高了实验精度.研究结果表明,在应力作用下,平行和垂直于应力方向传播的瑞利波发生了相应的变化:应力较小时,声速随应力变化较快;随着应力...

Experimental Study on the Surface Applied Stress Measurement with Rayleigh Wave

In this paper, experimental study of material's surface stress measurement by using the propagation characteristics of ultrasonic Rayleigh wave is presented. In measuring process, sing-around method was adopted to test small velocity change caused by applied stress. A series of fixtures were designed to acquire the steady coupling and elastic contact between probe and specimen, which simplified the testing setup and improved the accuracy degree. Results indicate that the presence of applied stress causes a regular velocity change of Rayleigh wave propagating along parallel and perpendicular to the stress direction respectively. The slope of relative velocity change is abrupt in the case of smaller stress, and a good linear relationship between the relative velocity change and the applied stress is presented with increasing of stress. Based on the character of tested results, the data were fitted sector by sector to reduce the error of stress measurement.