裂纹对金属磁记忆信号影响的试验研究

EXPERIMENTAL RESEARCH ON THE EFFECT OF CRACKS ON METAL MAGNETIC MEMORY SIGNALS

为分析构件应力集中区域裂纹对磁记忆信号的影响,分别对Q345钢材有裂纹和无裂纹两类菱形缺陷试件开展逐级加载拉伸试验,采集卸载后试件表面磁记忆信号,通过ABAQUS有限元模拟得出试件卸载后等效残余应力分布,对比分析磁记忆信号分布和演变规律,提取了4个反映磁记忆信号畸变程度的特征参数。结果表明:磁记忆信号可以反映残余应力扩展的演变过程;由于裂纹的存在,磁记忆信号的分布特征会发生改变;对磁记忆信号特征参数定量分析发现,裂纹的存在不会改变磁记忆信号畸变程度随外加荷载变化的整体规律,但是磁记忆信号畸变程度和其随荷载增大的速率都会增加。

In order to analyze the influence of cracks in stress concentration region on metal magnetic memory signals,step-to-step loading and tensile tests were carried out on two kinds of rhomboid defect specimens of Q345 steel with and without cracks,and the metal magnetic memory signals on the surface of the specimens after unloading were collected.The residual equivalent stress distribution of the specimens after unloading was obtained by ABAQUS finite element simulation.The distribution and evolution of metal magnetic memory signals were compared and analyzed,and four characteristic parameters reflecting the distortion degree of metal magnetic memory signals were extracted.The results show that the metal magnetic memory signals can reflect the evolution process of residual stress propagation,and the distribution characteristics of the metal magnetic memory signals will change due to the existence of cracks.Quantitative analysis of the characteristic parameters of metal magnetic memory signals shows that the existence of cracks does not change the overall law of the distortion degree of the metal magnetic memory signals with the increase of applied load,but both the distortion degree of metal magnetic memory signals and its rate will increase with the increase of load.