基于超声时域幅值能量衰减切向应力检测方法

Tangential Stress Detecting Based on Ultrasonic Time-Domain Amplitude Energy Attenuation

  • 摘要: 残余应力存在于机械构件生产的全生命周期中,准确有效地检测出机械构件内部残余应力,具有非常重要的意义. 针对现有检测方法难以精准表征构件内部残余应力,提出了一种基于超声时域幅值能量衰减的切向应力检测方法. 基于受载多晶体介质中超声波散射衰减理论,推导了瑞利散射范围内多晶材料超声波衰减系数,进一步提出了时域幅值能量衰减与残余应力对应的计算方法;搭建了切向残余应力加载系统,对采集的超声信号降噪处理;建立了线性回归和神经网络回归模型,与传统互相关计算声时差检测残余应力算法进行了对比. 试验结果表明,文中提出的超声时域幅值能量衰减切向应力检测方法检测精度优于声时差算法,其中神经网络回归建立模型精度最高,误差平均值为4.77 MPa,比声时差算法误差平均值减少了52.2%.

     

    Abstract: It is importance to detect accurately and effectively the residual stress existed in entire lifecycle of mechanical components. Due to the insufficiency of existed methods, a tangential stress detection method was proposed based on ultrasonic amplitude energy attenuation in the time domain to precisely characterize residual stress in components. First, using the attenuation theory of ultrasonic scattering in loaded polycrystalline media, the attenuation coefficient of ultrasonic waves within the Rayleigh scattering range of polycrystalline materials was derived, and a corresponding method was introduced to calculate amplitude energy attenuation and residual stress in the time domain. A tangential residual stress loading system was then established to minimize noise in the collected ultrasonic signals. Finally, linear regression and neural network regression models were built and compared with the traditional cross-correlation algorithm for residual stress detection. Experimental results show that the proposed ultrasonic time-domain amplitude energy attenuation method can achieve higher detection accuracy than the acoustic time difference algorithm, and the best performance can be exhibited with the neural network regression model. Its average error can reach to 4.77 MPa, and get a 52.2% reduction compared to the acoustic time difference method, making it highly applicable in engineering.

     

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