摘要
结构疲劳损伤测量和评估方法的研究是一个难点。由于疲劳损伤伴随材料磁特性的变化,且磁测法测量简单方便,所以利用材料磁特性测量和评估结构的疲劳损伤具有实际意义。以Q235钢为试件,通过构建疲劳损伤磁测试验平台,研究了循环应力下,基于磁滞回线的结构疲劳损伤磁测法。结果表明,疲劳损伤不同,磁滞回线也不同。提取磁滞回线的矫顽力H_c和剩磁B_r作为特征量进行分析,结果显示,试件失效前的疲劳过程大致分为两个阶段:首先是H_c和B_r的快速增大阶段,该阶段的H_c和B_r对疲劳损伤的灵敏度较高;然后是H_c和B_r的变化缓慢阶段,该阶段的H_c和B_r对疲劳损伤的灵敏度较低。最后分析了H_c和B_r与疲劳累积损伤D的变化关系,能够为结构疲劳损伤的定量评估及在线监测技术的研究提供基础。
The method of measurement and accurate assessment of structural fatigue damage is a challenging issue. In the process of structural fatigue damage, material magnetic properties changes, and the magnetic measurement is simple and convenient. Hence, it is significant to detect structure fatigue damage using the change of material magnetic properties. Using Q235 steel as test sample, this work focuses the magnetic measurement method of structure fatigue damage based on hysteresis loop under cyclic tensile stress, in which the test platform is set up. The results show that the hysteresis loop changes when the fatigue damage is different. The coercive force Hc and remanence Br of the hysteresis loop are extracted as feature parameters. The analysis results indicate that the whole fatigue process can be roughly divided into two stages before the specimen failure. Hc and Br rise rapidly in the first stage, whose sensitivity of the fatigue damage are higher. Comparatively, Hc and Br change slowly in the second stage, whose sensitivity of the fatigue damage are lower. Finally, the quantitative relationships of Hc, Br and fatigue accumulation damage D are analyzed. The proposed method can provide quantitative evaluation of the structural fatigue damage and on-line monitoring technology.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2017年第6期1474-1481,共8页
Chinese Journal of Scientific Instrument
基金
863课题(2015AA043702)项目资助
关键词
疲劳损伤
磁滞回线
矫顽力
剩磁
特征量
fatigue damage
hysteresis loop
coercive force
remanence
characteristics
