钢材磁通量与应力关系的磁力学模型及试验研究

A theoretical and experimental study on the dependency relationship of magnetic flux versus stress for stee

针对传统无损检测技术难以实现对在役钢结构的应力检测这一问题,提出了钢材等铁磁材料基于磁力耦合效应的全磁通应力磁性无损检测法,即通过测试钢材的全磁通量来测试其应力状态.根据钢材(铁磁材料的一种)磁感应强度的应力敏感这一特性,基于微磁能量理论,推导了磁感应强度同应力的关系方程,建立了磁通量增量与应力关系的磁力学模型.采用Q235钢材制作了2种模型试件,对其进行了磁力耦合试验.结果表明,试验结果与计算结果吻合较好,且2种模型试件磁通量的变化量均随着其拉应力的增大而增大,均随其压应力的增大而减小,且与外加应力呈较好的线性关系.

Aiming at the main characteristics of nondestructive testing for a real-time stress state in a long-span steel structure,the nondestructive testing（NDT） of stress with total magnetic flux was put forward for ferromagnetic materials such as steel.According to the stress sensitive characteristics of the magnetic induction intensity of ferromagnetic material and the theory of micromagnetic energy,the dependency equation of the magnetic induction intensity versus stress was reasonably derived,and the magnetomechanical model between the incremental magnetic flux and stress was also established.Meanwhile,two kinds of model specimens using Q235 steel were fabricated and then loaded by the magnetomechanical coupling tester.This investigation indicates that the theoretical and experimental results are in a good agreement,the change of the magnetic flux of both models increases with increasing tensile stress and decreases with increasing compressive stress,and exhibits a desirably linear relation to the applied stresses.