The Finite Element Analysis And Experiment Study On Cracks' Flux Leakage

In recent years, the method of MFL is widely used. Especially in the spoiled etch pit shape flaw testing research and the promoted application, magnetic flux leakage testing has already become the mature testing technology. In storage tank and pipeline service period, besides corrosion flaw existence, but also possibly forms many risky cracks flaw. Because the result of magnetic flux leakage testing contains many factors with influence, this increased the difficulty for the crack appraisal.This article proposed the theoretical model computation, the finite element simulation and experiments to carry on the analysis of the crack and solved a series of problems. First was the establishment of the rectangular trough theoretical model of different crack parameters (crack depth, crack width, crack angle and so on) have been analyzed and obtained the rule;Then separately obtained the crack stray field basing on the finite element method along with the magnetization design parameter (including the thickness of magnet, space of pole shoe, air gap and so on) , the rule of the crack parameters(including depth, width, angles, the space between two cracks and so on);Finally has carried on the confirmation through the experiment to above two methods partial analyses result. Because the crack stray field signal is small, this article has introduced the magnetism gathering installment, through the finite element analysis and the experiment has chosen a reasonable structure, and the curve is also obtained.Though establishing the theoretic model and experiments, the conclusion is obtained. By setting different parameters can get the curve of influence;Choosing the magnetism in reason can improve the effect of magnetization;Magnetism gathering technology is applied into Cracks' flux leakage testing, it can enhance the delicacy of testing.This study which do main on the crack's flux leakage will provide thereunder for magnetic flux leakage testing of the crack.