Simulation Research On Crack Detection Under Coating Based On ACFM

The advancement of science and technology has promoted the rapid development of society,and it has also made people pay more and more attention to high-quality life,and high-quality products often require high precision,high standards and high safety.For more than 50 years,it has been found that metal damage caused by metal fatigue is a major cause of various accidents.With the improvement of the level of basic science,various technologies have developed rapidly,especially the use of three-dimensional equipment has greatly improved the detection technology.There are dozens of material damage detection techniques,most of which have been applied in the actual production process.However,due to the low contrast between defect areas and non-defect areas,noise and similarity of subtle defects,surface defect detection techniques still face the problems of slow detection speed and low recognition accuracy,especially damage detection methods for surface coating materials.ACFM has been widely used in material damage detection due to its non-contact and noncorrection technical advantages.Therefore,based on the COMSOL multiphysics simulation software and Maxwell's electromagnetic field theory,this paper proposes an alternating electromagnetic field detection technology,and establishes a detection system model to detect the damage of the coated material(hereinafter referred to as the material under the coating),thereby To achieve the purpose of high-precision damage detection of the material under the coating.By studying the electromagnetic nondestructive testing theory and the application of Maxwell's expression in the electromagnetic field,this subject deduces the mathematical models of the alternating electromagnetic field and the rectangular coil excitation electromagnetic field.Simulation model.Through the analysis and study of the electromagnetic field signal,the magnetic field characteristic signal that characterizes the crack position and geometrical parameters is found,and the functional expression between the crack signal and the magnetic field characteristic signal is established.By studying the influence degree of the detection system parameters on the electromagnetic field in the detection system,the influence degree of the coil parameters and excitation signal on the detection system is determined,and the coil length,width,height,number of turns,lift-off distance,excitation current amplitude and frequency are determined.After optimizing the system parameters,the optimal detection system parameters were finally determined.Finally,using Python language and Py QT,My SQL,Matplotlib and other library functions,the storage and extraction of test data,the acquisition of magnetic field characteristic signals,the quantitative identification of cracks,and the design of test signal visualization interface are completed.Modular design and function realization tasks.Finally,the visualization platform of the ACFM test system is built.