Simulation Analysis Of Surface Eddy Current Inspection Of Steel Roller Based On Finite Element Method

Eddy current nondestructive testing is one of the five conventional nondestructive testing technologies.Based on the eddy current inspection as an opportunity to outline the advantages of eddy current testing technology,the list of eddy current testing technology development situation at home and abroad and the present situation,the mathematical model for eddy current testing system for the center of gravity modeling simulation calculation and analysis,throughout the research direction and research results at home and abroad,on the basis of predecessors' defect quantitative analysis of the new ideas are put forward.In order to establish a correct mathematical model,starting from the basic theory of electromagnetism and combining with the basic working principle of eddy current sensor,it is shown that the essence of eddy current inspection is the change of coil impedance,thus causing the change of electrical signal output.This paper introduces the equivalent circuit diagram of eddy current testing,deduces the equivalent resistance equation of the eddy current sensor in operation,selects the placement coil probe suitable for this paper,and expounds the factors restricting the detection of the placement probe coil.By means of the implied relation between maxwell's equation and electromagnetic field,the parameter expression of eddy current magnetic field is deduced.Detail is commonly used in ANSYS electromagnetic modeling and simulation of boundary conditions,structures,field-circuit coupling model of three-dimensional eddy current flaw detection of slotted length of crack defect,the width and radius of simulation analysis and calculation,summarizes crack defects regularity of detecting coil output voltage change,from the perspective of the relationship between volume and the electric potential difference value of crack,to fit the simulation data and calculation,the result of the formula and finite element calculation results are compared,that error.As the core component of eddy current sensor,the resolution of probe coil is particularly important.ANSYS is adopted to establish the mathematical model of three dimensional geometric structure parameters of cylindrical excitation coil simulation and calculation of drive coil is derived of the difference of the inner and outer radius of the equivalent radius,thickness,three measured on geometric structure parameters and the variation of the magnetic induction intensity and magnetic induction intensity,the relationship between,through comparing the theoretical value and simulation value,which provides proof for the correctness of the mathematical model.Through the above simulation calculation,cylindrical probe is used to detect the defects of stainless steel steel roller,and the quantitative evaluation of surface defects of the steel roller is completed.It is proved that the defect volume is within a certain range,and the crack condition can be determined according to the calculation of the fitting formula.The influence of the geometrical structure parameters of the probe coil on the resolution is explained,and the coil probe with higher resolution can be selected for flaw detection by means of simulation calculation science.The simulation results show that the mathematical model is correct and feasible.