Research On Magnetic Memory Nondestructive Testing Technique

MMM(Metal Magnetic Memory)technique is a new technique in the field of nondestructive detecting.It's very suitable for the diagnosis before ferromagnetic parts failure,and has great potential in the estimation of fatigue intensity and life especially. But now the phenomenon of MMM studies on the mechanism still is not perfect,so the study theory of MMM testing accuracy to improve paper has an important significance based on the theory and experiment simulating two aspects, system analysis in the process of ferromagnetic axial load the magnetic force changes relationship.First, this article deduce the equation of force-magnetic relation form least energy principle and molecular field theory when the stress and magnetic field direct parallel in the earth's magnetic field from magnetic and elastic basic theory.Then, in assumptions magnetic field, this article deduces that the general case stress-magnetic relation equation through least energy principle and molecular field theory when the stress and magnetic field direct into certain angle.Finally, this article analysis the theoretical calculation and simulated experiment.First this article get the system of equation of the magnetic field intensity method to weight and magnetic field intensity tangential component form electromagnetic field theory, and then it gets the constitutive of extension sleeves located in geomagnetic field environment through the least energy principle and electromagnetism knowledge, and be imposed boundary conditions simulated by software, it concludes that the component surface and internal magnetic field distribution.Above of all the work provides some basic theory for exploring magnetic measurement stress technology, the article get the equation from analysis the relation of stress-magnetic,stress-magnetisability in the ferromagnetic bearing carrier.