利用磁记忆信号特征参数表征拉伸应力状态

发布时间：2018-01-16 19:25

本文关键词：利用磁记忆信号特征参数表征拉伸应力状态　出处：《振动.测试与诊断》2017年04期 　论文类型：期刊论文

【摘要】：通过对Q345B钢试件静载拉伸时法向磁场的在线测量,得到了不同载荷作用下的磁信号特征,研究了试件断裂处法向分量H_p(y)和特征参量随应力的变化,并建立了磁场梯度指数与应力的量化关系。试验结果表明:当拉应力大于308 MPa时,H_p(y)相对于弹性阶段磁信号发生反转现象;根据梯度最大值K_(max)的极大值可准确判定试件是否进入塑性阶段;梯度最大值的算术平均值K_(max)~(avg)随应力变化的3个阶段分别对应力-位移曲线的弹性阶段、塑性阶段和破坏阶段;K_(max)~(avg)值和断裂处H_p(y)值均可反映试件的损伤程度;梯度指数ξ值可表征试件的应力状态。分析结果表明:Jiles-Atherton模型可解释磁信号的反转现象;感应磁场模型可定性解释试件断裂处的磁信号变化原因,与试验结果一致。该研究为利用磁记忆检测技术进行应力表征提供了一种有效方法。
[Abstract]:Based on the Q345B steel specimen static tensile method to on-line measurement of the magnetic field of the magnetic signal characteristics under different loads has been studied, the fracture of the specimen at the normal component H_p (y) and the change of parameters with stress, and the establishment of a magnetic field gradient index to quantify the relationship between stress test. The results show that when the tensile stress is greater than 308 MPa, H_p (y) relative to the elastic magnetic signal reversed phenomenon; according to the gradient maximum value of K_ (max) maximum can accurately determine whether the specimen into the plastic stage; the K_ value of the maximum gradient arithmetic average (max) ~ (AVG) with the elastic stage 3 stages of stress change corresponding to the force displacement curve of the plastic stage and failure stage; K_ (max) ~ (AVG) and H_p (y) fracture value can reflect the damage degree of the gradient index; zeta value can by stress state. The analysis results show that: the Jiles-Atherton model can explain The reversal phenomenon of magnetic signals can be qualitatively explained by the induction magnetic field model, which is consistent with the experimental results. The research provides an effective way to stress characterization by magnetic memory testing technology.

【作者单位】：西安建筑科技大学土木工程学院;
【基金】：国家自然科学基金资助项目(51578449,51478383,51378413) 陕西省自然科学基金资助项目(2015JM5192)
【分类号】：TG142.15
【正文快照】： 引言铁磁构件由于其具有轻质高强、材质均匀、制作简单、韧性好和耐高压等特点,被广泛应用于机械和建筑领域。但这些构件的受力和构造复杂,在服役过程中遭受长期循环载荷、自然灾害以及人为因素的影响,不可避免地产生一些隐性损伤,威胁整个设备和结构的正常使用和安全。常规的

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