超声波应力测试降噪技术

Noise reduction technology of ultrasonic stress test

主要分析临界折射纵波(LCR波)降噪处理对于A7N01铝合金与S355J低合金钢残余应力测试的必要性。通过拉伸标定的方式分别标定A7N01与S355J,并对比降噪与未降噪信号的局部细节,最后拟合降噪与未降噪信号的标定结果。通过上述试验分析发现,超声在铝合金中的传播特征受应力的影响更为明显,LCR法对于S355J的应力降噪非常必要,而A7N01应力测试可以不做降噪处理。

The necessity of the noise reduelion on longitudinal critical refraction（ LCR ） wave for measuring the residual stress of A7N01 aluminum alloy and S355J low alloy steel are analyzed. And the calibration processes of A7N01 and S355J are respectively realized by the method of stretching, and the local details of noise reduction signal and noise signal are compared,and the calibration result of noise reduction signal and noise signal is finally proposed. Above experimental analysis shows that the influence of stress on the characteristics of uhrasonic transmission in aluminum alloy is more obvious. Noise reduction is very necessary for the stress in S355J measured by LCR method,while the noise reduction can be ignored for the stress test of A7N01.