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Compared with traditional I-steel, the surface of wing of H shape pillar is parallel each other, the structure is convenient; Wing is wide, the stiff of side direction is great; It is good to resist curved, the surface is bright and clean, and the H shape pillar is shaping, have good economic and social benefits. The H shape pillar has extensive application in the actual project, such as house, factory building, bridge, etc..However, while developing in a more cost-effective manner in steel construction, we must see whether no matter foreign countries or our country, had taken place a lot of different kinds of reasonable accident of intensity. Accidents such as World Trade Center building, New York of U.S.A., collapse among ’9.11’ incident with a loud crash among them, the South snow storm, Hunan electricity Tamerlan,etc, causing the losses of great casualties and economic property 2008. This detection and appraisal on stell-structured security have put forward higher requirement, and this subject will study for the problem, has important meaning at project practical application just.The people have carried on amount of research and made a lot of achievements to the emergency test technology of the stell-structured stress domestic and internationally, but the test has the problem that is common, that is when permanently initially load already finished, we can not measure receiving the strength situation of structural body by traditional method again. How to monitor the absolute stress of the steel construction of active service, it is the structure difficult point question of technical field.The dissertation adopt experimental method, we build up experimental system, by alterring the frequency of magnetic induction loop and the outside magnet space, we get the experiment datas about stress and induced electromotive force under different frequency. We also get the electrical spectrum lines which reflect the relationships about induced electromotive force, stress and frequency. The feature of spectrum shows the one-to-one corresponding ships between stress and the electrical spectrum, and with the stress level rising, the curve of induced electromotive force gradually drops. The orderliness of spectrum curves corresponding to different stresses are similar, and do not cross. At the same time, with the stress level rising, the induced electromotive force also drops, but the reductive degrees of different frequency are different. With the frequency rising, every stress spectrum curves are gradually dropping, and this condition makes the whole decreasing trend of the spectrum.This article also builds the mathematics expressions for the axial compressed and eccentrical load H shape pillar at the same frequency state, and the expressions reflect the relationship between induced electromotive force and stress, and the relationship between induced electromotive force and strain. We establish the expressions between induced electromotive force and frequency by fitting the stress electrical spectrum lines curves of H shape pillar. In addition, this artical sets up the slope comparison method and least square method to identify stress by using the character of spectrum lines.
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