基于磁记忆的Q235b受弯钢梁力磁效应数值模拟

Numerical simulation of stress-magnetization effect for bending states of Q235b steel beam based on magnetic memory

为推进金属磁记忆检测技术在建筑钢结构领域的应用,量化金属磁记忆信号与构件应力状态之间的关系,本文以建筑钢框架中常见的工字型钢梁为例,采用ANSYS有限元分析软件,结合应力与磁导率的磁机械耦合模型,对不同载荷工况下的受弯钢梁进行力-磁耦合有限元模拟研究。通过对比集中力作用下4点受弯工字钢梁的试验结果与有限元计算结果,发现二者的漏磁场磁感应强度法向分量B(y)曲线及其峰峰值ΔB(y)具有较好的一致性,证实了模拟方法的可行性与准确性。考虑钢框架在正常使用中的实际受力状态,利用上述模拟方法,对均布荷载作用下两端固结工字钢梁进行力-磁耦合有限元模拟。结果表明,均布荷载作用下漏磁场磁感应强度法向分量B(y)和漏磁场法向分量梯度K(y)曲线均在应力最大和最小处发生突变,且漏磁场法向分量梯度K(y)曲线能较好地反应钢梁应力最大和最小变化区域、幅度和趋势。提出了用应力集中截面磁信号法向分量的平均值B(y)avg和磁信号法向分量梯度的平均值Kavg表征钢梁在该截面应力变化情况。

In order to promote the application of metal magnetic memory detection technology in the field of building steel structures,and to quantify the relationship between metal magnetic memory signals and component stress states,this paper takes the common I-beam in building steel frames as an example,using ANSYS finite element analysis software,combined with the magnetic-mechanical coupling model of stress and permeability,The stress-magnetic coupling finite element simulation of steel beams under different loading conditions is studied.By comparing the concentration under the action of four-point bending test results and finite element calculation results of I-steel beam,found that the curve of the normal component of leakage magnetic field of magnetic induction intensity B(y)and its value of peak ΔB(y)has a good consistency,which confirmed the feasibility and the accuracy of the simulation method.Taking into account the actual stress state of steel frame in normal use,the above simulation method is used to conduct the force-magnetic coupling finite element simulation of the fixed I-beam at both ends under uniformly distributed load.The results show that the curves of the normal component B(y)and the gradient of the normal component K(y)of leakage magnetic field of magnetic induction intensity under uniformly distributed loads mutate at the point of maximum or minimum stress,and the magnetic signal gradient curve can well reflect the region,amplitude and trend of the maximum and minimum stress variation of the steel beam.the average value of the normal component of magnetic signal B(y)avg and the average value of the gradient of normal component magnetic signal Kavg at the stress concentration section was proposed to represent the stress variation of steel beam at this section.