超声表面波检测金属材料表面应力的实验研究

本文应用声弹性理论研究了表面波在金属材料表面的传播速度和表面应力之间的关系,优化了表面波声弹性公式,建立了应力和表面波相对传播时间差的关系。通过构造实用的微型表面波探头,采用数字相关法计算了不同应力下的表面被传播时间差,确定了A3钢的表面波传播时间差与应力的关系式。同时分析了试件表面粗糙度和平整度对表面波速度变化的影响,最后给出了金属材料在不同表面条件下的实验分析结果。

Experimental Study on the Metal Material Surface Stress Measurement Using Surface Wave Technique

In this paper,the relation between the surface wave propagation speed and the surface stress of a metal material is studied in theory and experiment.A formula for calculating the stress based on the surface wave acoustoelasticity is optimized.A pair of surface wave sensors with 5MHz in frequency is well prepared for the research.The flying-time difference between two ultrasonic echoes is calculated by application of the correlation method.Some experimental results of the flying-time difference under different surface stress are successfully demonstrated by a specimen made of A3 steel.Finally the effects of the roughness and flatness of specimen on the surface wave speed are carefully analyzed,and the methods for resolving the problem are verified by the experiment.