基于小波变换的金属材料声发射特性研究

Research on Acoustic Emission Characteristics of Metal Material Based on Wavelet Transform

以Q235-B碳钢和0Cr18Ni9不锈钢为研究对象,分别对其在塑性变形和裂纹扩展时产生的声发射信号进行检测,运用小波变换分析检测信号来研究材料的声发射特性。结果表明,碳钢产生声发射信号经db5小波6级分解后,d5级信号占的能量比例最大,其峰值对应频率基本在166～176kHz内,裂纹扩展时这一级信号所占能量比例较塑性变形时高;不锈钢产生声发射信号经同样变换后,d6级信号占的能量比例最大,其峰值对应频率基本在88～112kHz内,裂纹扩展时这一级信号所占能量比例较塑性变形时高。

The acoustic emission signals were measured during plastic deformation and crack propagation in Q235-B and 0Cr18Ni9 stainless steel. Wavelet transform was applied to analyze inspection signal for investigating the acoustic emission characteristics of material. The results show that the acoustic emission signal of carbon steel is analyzed by six layer db5 wavelet transform, the most energy is concentrated in d5 level. Peak frequency is located in the range of 166-176 kHz. Energy ratio in d5 level is higher during crack propagation than palstic transform. While the acoustic emission signal of stainless steel through the same wavelet transform, the most energy is concentrated in d6 level. Peak frequency is located in the range of 88-112 kHz. Energy ratio in d6 level is higher during crack propagation than palstic transform.