基于相关峰值插值法的超声应力测量

Research on Ultrasonic Stress Measurement Based on Correlation Peak Interpolation

提高超声应力测量精度的关键在于准确测量超声波在构件中的传播时间。通过分析超声应力测量的原理,揭示了超声波传播时间与构件应力的关系。为了提高测量结果的抵御噪声的能力,对接收的超声信号采用相关运算法测量其传播时间,并提出改进的算法,避免了由探头参数差异导致的误差。此外,为获得更加准确的传播时间,对相关函数序列在峰值附近做抛物线插值。试验结果显示,采用改进的相关运算方法能够提高传播时间的测量精度,测量值具有良好的线性度,对提高超声应力测量精度具有实际意义。

The key of improving the ultrasonic stress measurement accuracy is to measure ultrasonic travel-time accurately. The relationship between the ultrasonic wave travel-time and stress was revealed through the analysis of the principle of ultrasonic stress measurement. In order to improve the ability to resist noise of the measurement results, correlation algorithm was used to calculate the travel-time, and the improved algorithm was put forward to avoid errors caused by differences in parameters of transducers. In addition, a more accurate travel-time could be obtained by interpolation near the peak of correlation function array. Experiment re- suits show that the improved algorithm can improve the measurement accuracy of the travel-time because the results get a good line- arity. The method is of practical significance for improving the ultrasonic stress measurement accuracy.