超声激励下的裂纹区域温度缺陷信号特征分析

Characteristic Analysis of Temperature Defect Signal in Crack Region under Ultrasonic Excitation

以平板类试件贯穿裂纹为研究对象,采用超声脉冲作为激励源,对裂纹区域温度空间分布规律和温度随时间变化规律进行了分析研究。首先建立了裂纹区域热传导模型,再通过对其在二维平面内的传热及温度分布进行仿真,将缺陷生热模拟成脉冲热源,分析了超声激励下裂纹区域温度峰值与热量的变化情况。然后总结出温度空间与时间分布特征,并提出了裂纹区域温度缺陷信号判断标准,最后通过实测数据验证了温度时间空间分布特征及判断标准的有效性。

The penetrating crack of flat specimen is taken as the research object and ultrasonic pulse is used as the excitation source to analysis the spatial distribution law of temperature in the crack area and the law of temperature change with time.First,a model of heat conduction in the crack region is established based on the penetrating crack of plate specimen.Then the heat transfer and temperature distribution in the two-dimensional plane were simulated.And the changes of the peak temperature and heat in the crack area under ultrasonic excitation were analyzed,while the defect heat generation was regard as pulse heat source.Then the characteristics of temperature spatial and temporal distribution were summarized,and the criteria for judging the temperature defect signal in the crack area are proposed.Finally,the efficiency of characteristics and criteria for judging the temperature temporal and spatial distribution is verified by the measured data.