拉伸荷载作用下桥梁拉索钢丝/钢筋的力-磁效应研究  

Stress-magnetic Effect of Bridge Cable Wire and Steel Under Tensile Load

作　　者：何峻峰 江胜华[1,2] 孙伟贺 王廉强 HE Junfeng;JIANG Shenghua;SUN Weihe;WANG Lianqiang(College of Engineering and Technology,Southwest University,Chongqing 400715,China;School of Civil Engineering,Wuhan University,Wuhan 430072,China)

机构地区：[1]西南大学工程技术学院,重庆400715 [2]武汉大学土木建筑工程学院,武汉430072

出　　处：《材料导报》2023年第13期215-222,共8页Materials Reports

基　　金：国家自然科学基金(51208078);重庆市技术创新与应用示范社会民生类项目(cstc2018jscx-msybX0028);中国博士后科学基金(2017M622977);重庆市博士后科研项目特别资助(XmT2018028)。

摘　　要：拉伸荷载作用下拉索钢丝/钢筋在弹塑性全过程的力-磁效应及力-磁反转现象的研究尚不充分,且现有试验中存在环境干扰磁场,严重影响磁场试验的准确性。研制了拉伸荷载作用下拉索钢丝/钢筋应力的磁场测试的无磁试验系统,采用试验和有限元研究了钢筋受拉弹塑性全过程钢筋自身的磁感应强度及磁场梯度与应力的关系。试验结果表明,在应力为0~175.9 MPa时,磁畴的变化以磁畴壁移为主,随着应力增大,钢筋磁导率增大,钢筋自身的磁感应强度B_(y)和磁场梯度B_(yz)的绝对值增大;在应力大于175.9 MPa至接近断裂时,磁畴的变化以磁畴旋转为主,随应力(应变)增大,钢筋磁导率降低,钢筋自身的磁感应强度B_(y)和磁场梯度B_(yz)的绝对值减小。钢筋自身的磁感应强度B_(y)及磁场梯度B_(yz)绝对值的平均值与应力的曲线均在175.9 MPa发生反转,反转点对应的应力小于屈服强度(584.3 MPa)。有限元计算的钢筋自身的磁感应强度B_(y)和磁场梯度B_(yz)随应力的变化规律与试验基本一致。对于钢筋受拉弹塑性全过程的磁感应强度及磁场梯度绝对值的平均值与应力的关系,试验值和有限元计算值及拟合值三者非常接近,可为拉索钢丝/钢筋应力的磁场监测提供参考。The current research on the stress-magnetic effect and reversal effect on cable wire and steel during the entire elastoplastic process under tensile load is limited.Moreover,the existing test method is influenced by environmental interference magnetic fields,which significantly affect the accuracy of the magnetic field-based test.The nonmagnetic experimental method is developed for the magnetic testing of stress in cable wire and steel under tensile load.Experiment and finite element analysis(FEA)are used to investigate the relationship between the steel’s magnetic field intensity,magnetic gradient,and stress during the entire elastoplastic tension process.When the stress was smaller than 175.9 MPa,the change in the magnetic domain was dominated by wall shifts.As the stress increased,the magnetic permeability of the steel bar increased,and the absolute values of the magnetic field intensity B_(y) and magnetic gradient B_(yz) increased for most measuring points.When the stress was greater than 175.9 MPa(before fracture),the change in the magnetic domain was dominated by rotation.As the stress or strain increased,the magnetic permeability of the steel bar decreased,and the absolute values of B_(y) and B_(yz) decreased for most measuring points.The relationship between the mean of the absolute values of B_(y) and B_(yz) and stress is reversed when stress is 175.9 MPa,which is smaller than the yield strength(584.3 MPa).The B_(y) and B_(yz) values of steel calculated by FEA are relatively consistent with the experimental results.During the entire elastoplastic procedure under tensile load,experimental values,calculated values by FEA,and fitted values were very similar in terms of the relationship between the mean of the absolute values of B_(y) and B_(yz) of steel and stress,which may be used as a reference for magnetic monitoring of stress in cable wire and steel stress.

关 键 词：拉索钢丝 钢筋 力-磁效应 磁感应强度 磁场梯度 

分 类 号：TH140.7[一般工业技术—材料科学与工程] TG115.28[机械工程—机械制造及自动化]