针对钢腐蚀疲劳损伤的非线性Rayleigh波检测方法

针对钢腐蚀疲劳损伤的检测和评价,提出了一种非线性Rayleigh表面波的检测方法。搭建了RAM-5000-SNAP非线性超声检测系统,采集了Rayleigh表面波非线性信号,建立了疲劳周期过程中相对非线性参数A_2/A_1~2与腐蚀疲劳寿命之间的关系。为了提高该检测方法的准确度,采用小波包分解法实现降噪处理。研究结果表明,相对非线性参数在腐蚀疲劳过程中具有先增加后保持平稳最后又急速增大的变化趋势,并且急速增大点在试件出现弯曲变形时出现。因此,非线性Rayleigh波检测方法可以实现钢腐蚀疲劳损伤的无损检测。

Nonlinear Rayleigh wave detection method for corrosion fatigue damage of steel

In order to detect and evaluate corrosion fatigue damage of steel, a nonlinear Rayleigh surface wave detection method is proposed. The RAM-5000-SNAP ultrasonic nonlinearity detection system is built, the Rayleigh surface wave nonlinear signal is collected, the relationship between the relative nonlinear parameter A2/A12 and the corrosion fatigue life during the fatigue cycle is established; and in order to improve accuracy of detection method, wavelet packet decomposition method is used to realize the noise reduction process. Experimental results show that relative nonlinear parameters have a tendency of increasing at first, then keeping steady and finally increasing rapidly in the process of corrosion fatigue, and the rapid increase point appears when specimen appears bend deformation. Therefore, the nonlinear Rayleigh wave detection method can be used for nondestructive evaluation of corrosion fatigue damage of steel.