温度影响下基于应力波的钛合金试件疲劳裂纹监测实验研究

Experimental Study of Temperature Effect on Fatigue Crack Monitoring for Titanium Alloy Specimen Based on Stress Wave

本文对温度影响下应用应力波监测钛合金CT试件中的疲劳裂纹进行了研究。建立了由MTS材料试验机和温控箱组成的实验装置,模拟温度变化对应力波在钛合金试件中传播的影响。采用PZT压电元件分别在试件中激励和接收应力波信号。通过连续小波分析,提取应力波信号的多种特征用于表征疲劳裂纹的发生与发展,并对信号特征进行了统计分析。为在温度变化下监测钛合金试件中的疲劳裂纹,对信号特征进行多元偏值分析,采用马氏平方距离融合多个信号特征,在概率统计意义下确定钛合金试件中是否存在疲劳裂纹。实验结果表明了所提出方法的可行性和有效性。

This paper presents the study results of temperature effect on fatigue crack monitoring for titanium alloy CT specimens based on stress waves.An experimental device consisting of MTS testing machine and electrical temperature control oven was established to simulate the effect of temperature on stress wave propagation in titanium alloy specimens.PZT piezoelectric elements were adopted to excite and receive stress wave signals in specimen,respectively.By using continuous wavelet transform（CWT）,various features of stress wave signal were extracted for characterizing the occurrence and development of fatigue cracks,and statistical analysis of signal characteristics was conducted.To monitor the fatigue crack development in titanium alloy specimen under condition of temperature variation, a multi-variable outlier analysis was adopted, and multiple signal characteristics were integrated by Mahalanobis squared distance to determine whether there is fatigue cracking in titanium alloy specimens under probabilistic statistical significance.The feasibility and effectiveness of above proposed method are validated by experimental results.