摘要
金属浅表层的微裂纹直接影响金属的性能和使用寿命,非线性超声检测方法对于浅表层微缺陷检测有较好的效果。本文针对钢材浅表层微缺陷检测和定位问题,通过有限元仿真的方式研究裂纹检测与定位的非线性超声规律。在有限元仿真软件COMSOL Multiphsics中建立包含表层裂纹的二维混频表面波检测模型,研究超声波与钢材表层裂纹引起的非线性效应,总结缺陷尺寸与边频信号振幅的变化关系,采用基于时频分析的异侧混频激励方案研究裂纹的定位。仿真结果表明,当金属表面存在裂纹时,检测点接收的回波信号中将出现和频及差频信号;边频信号的信号强度随着裂纹宽度增大而增强,随着检测距离的增大而衰减,随着裂纹深度增加呈现先增后减趋势;通过时频分析实现了表面裂纹的定位。采用激励频率分别为0.5 MHz和0.8MHz、基频幅值均为10^(-5)m的超声信号能够满足浅表面裂纹检测需求,实现浅表面深度为0.2~2 mm、宽度为5~30μm的裂纹检测,定位准确率为88%。研究结果为钢材浅表层微缺陷的非线性混频超声检测和定位提供了参考依据。
Shallow surface microcracks in metals can directly affect the performance and service life of metals,and nonlinear ultrasonic detection methods have shown excellent results for detecting shallow surface defects.This paper studies the nonlinear ultrasonic laws of crack detection and positioning for shallow surface defects in steel through finite element simulation.The paper also establishes a two-dimensional frequency-mixing surface wave detection model that includes surface cracks in finite element simulation software,namely COMSOL,studies the nonlinear effects of ultrasound waves and surface cracks in steel,summarizes the relationship between defect size and side frequency signal amplitude changes,and uses an opposite-side frequency-mixing excitation scheme based on time-frequency analysis to study crack positioning.The simulation results show that when there is a crack on the metal surface,the sum frequency and difference frequency signals will appear in the echo signal received by the detection point,and the strength of the side frequency signal increases with the increase in crack width,attenuates with the increase in detection distance,and shows a trend of first increasing and then decreasing with the increase in crack depth;the positioning of surface cracks is realized by timefrequency analysis.By using ultrasonic signals with excitation frequencies of 0.5 and 0.8 MHz and a fundamental frequency amplitude of 10^(-5) m,shallow surface cracks with a depth of 0.2~2 mm and a width of 5~30μm can be detected,and the positioning accuracy reaches 88%.These results provide a reference for the nonlinear frequency-mixing ultrasonic detection and positioning of shallow surface microdefects in steel.
作者
刘智勇
郑隆浩
刘新海
唐立军
Liu Zhiyong;Zheng Longhao;Liu Xinhai;Tang Lijun(School of Physics&Electronic Science,Changsha University of Science&Technology,Changsha Hunan 410114,China;Hunan Province Higher Education Key Laboratory of Modeling and Monitoring on the Near-Earth Electromagnetic Environments,Changsha Hunan 410114,China;Hunan Provincial Key Laboratory of Flexible Electronic Materials Genome Engineering,Changsha Hunan 410114,China)
出处
《硬质合金》
CAS
2023年第3期209-217,共9页
Cemented Carbides
基金
湖南省研究生科研创新项目《谐波法非线性超声检测系统设计与实现》(编号CX20210742)
长沙理工大学物理与电子科学学院科研助推项目《金属纳米颗粒中表面等离激元的量子效应研究》(编号2019QJCZ017)。
关键词
非线性混频法
有限元仿真
和差频信号
浅表层裂纹检测与定位
nonlinear frequency-mixing method
finite element simulation
sum and difference frequency signals
shallow surface crack detection and positioning
