不同参变量对缺陷脉冲信号的影响

Study on the Influence of Different Parameter Variables on Defect Pulse Signal

焊接结构件在压力容器、航空航天等领域得到广泛的应用。焊缝中常见的缺陷:夹渣、裂纹和气孔将导致材料承受的应力极限有所差异,目前对此类缺陷难以进行定性识别。为此,利用有限元仿真技术对超声相控阵检测开展缺陷定识别研究。模拟含缺陷相控阵检测实验,针对不同声源频率与缺陷尺寸计算模型进行数据提取,计算缺陷信号的反射系数;通过快速傅里叶变换获得缺陷特征频率,并比较其与声源频率的偏离程度;对比不同缺陷的特征频率与缺陷尺寸的敏感度。仿真结果表明,当声源频率较低或缺陷尺寸较小时,3类缺陷的特征表现出明显的差异。为识别缺陷类型提供了一种有效的方法。

Welded structural parts are widely used in pressure vessels,aerospace and other fields.Common defects in welds have slag inclusions,cracks,porosity which may cause differences in the stress limits of the material.The defects are currently difficult to qualitatively identify.Therefore,finite element simulation technology is used to carry out qualitative defect identification on ultrasonic phased array detection.The phased array detection experiment containing defects is simulated,the data are extracted according to different sound source frequencies and defect size calculation models,and the reflection coefficient of defective signals is calculated.The characteristic frequencies of defect are obtained by fast Fourier transform,and the degree of deviation from the frequency of the sound source is compared.Finally,the characteristic frequency of different defects and the sensitivity of defect size are compared.The results show that when the sound source frequency is low or the defect size is small,the characteristics of the three types of defects show obvious differences.This provides a favorable way to identify the type of defect.