Experiment Research On Measuring Of Stress-Induced Electromotive Force Of Steel Truss

As a hotspot recent years, the steel structure is widely applied in various fields. Steel truss is a very important structure, and it is widely applied, for example the steel roof truss, steel bracket, steel alley way, steel askew bridge, pipe support grade and so on. We could see shadow of the steel truss in a great many entity construction, for example large-scale gymnasia, exhibition center, the steel roof of the large-scale emporia, the wide span steel roof of the aerodrome departure hall, wide span steel bridge, heavy duty industrial premises, higher level steel structure construction and so on.It is the best occasion for development of steel structure, at the same time, steel structure accidents is so fatal. At present, the cardinal measuring and testing technique of steel truss can be listed as follows:resistance strain-gauge transducer, optical fibre sensor, vibrating string sensor, partial stress releasing method, MAE magnetic-acoustic farad and magneto-elasticity means. All these measuring and testing techniques mostly rely on deformation to measure structure stress, but once structure deformation finished, it is very hard to use them to measure structure stress which is generated by permanence loads. For the sake of make up the shortage of steel structure measuring and testing techniques, we do experimental research on steel structure members stress electromagnetic effect, and expect to timing supervise stress variety of steel structure members.The dissertation adopt experimental method, we build up experimental system to apply axial concentrated force for steel truss, then to do experimental measuring research on stress, strain and induced electromotive force of steel truss. We found the mathematic model and common mathematic representation between stress, strain and induced electromotive force by analyzing and treating experimental data. According to mechanics principle and electromagnetism theory, we probe in the internal relation of stress and induced electromotive force of the steel structure members.The experimental results indicate that when the magnetic core of sensing coil is placed perpendicular with the truss member, the magnetic circuit which is formed by magnetic core and wing edge ofâ… -iron plumbs with stress direction, the electromotive force gradually fall down with the increase of compressive stress under the compressive stress action; the electromotive force gradually rise gradually with the increase of tensile stress under the compressive stress action. When the magnetic core of sensing coil is placed parallel with the truss member, the magnetic circuit which is formed by magnetic core and round steel bar parallels with stress direction, the electromotive force gradually rise gradually with the increase of compressive stress under the compressive stress action; the electromotive force gradually fall down with the increase of tensile stress under the compressive stress action. During the experiment the stress and strain have linear parabola relation variation with induced electromotive force.At the same time we establish the mechanical analysis model of steel truss with Midas/civil, calculate the stress of measuring point for every member, and contrast the computational to the solution test result. Then we analyses the reason which cause the error in order to further improvements experiment theoretical analysis. The results show that the experimental data come close to the theoretical calculation. We may decrease experimental error through perfecting test system.