Experimental Research On Stress Electrical Spectrum Lines Of Square Steel Tube

It is impossible to measure the actual working stress of steel structure by using the measuring techniques relying on strain, while the deformation caused by permanence loads has been accomplished. To enrich the measuring techniques of steel structure, outside magnetic field is settled towards the examined unit, which helps produce induced electromotive force in the steel structure unit. And then the stress of unit can be tested by the change of the induced electromotive force. Academicians have done some exploration and received some research production. On the basis of the studies from forefathers, this article carries through the experimental researches on stress electrical spectrum lines of square steel tube.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 square steel tube 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, which largely enrich the formulas under the frequency of 50Hz which seniors concluded. We establish the expressions between induced electromotive force and frequency by fitting the stress electrical spectrum lines curves of square steel tube. In addition, this artical set up the slope comparison method and induced electromotive force amplitude ratio method to identify stress by using the character of spectrum lines.