Defect Detection Model Analysis And Device Design Based On AC Electromagnetic

Pipeline transportation plays an important role in oil and gas resources transportation because of its reliability and economy.However,the failure of oil and gas pipelines will have a huge impact on the whole industrial safety and environmental safety.Therefore,it is extremely important to ensure the safe and stable operation of oil and gas pipelines.Most of the existing devices for pipeline diagnosis are of high cost and low detection efficiency.This thesis focuses on one of the technologies-AC electromagnetic detection to carry out research,the main work is as follows:Firstly,the classical electromagnetic field theory model is analyzed.In the meanwhile,the principle of ac electromagnetic detection is researched and the analytical model of electromagnetic detection.Also,the corresponding analytical solution is given,on this basis,the corresponding numerical model is established and the numerical model is analyzed.Finally,it puts forward some key parameters under the model of the theory in this thesis.Secondly,in view of the limitations of traditional defect detection methods,a joint analysis method of analytical model and numerical model was designed to explore the rule between key parameters of the model and detection results.Firstly,the corresponding analytical relationship is given based on the specific physical environment in this study,including the excitation parameters of test pieces,testing probe space distribution state,physical state of the probe and defect size,location and shape.Based on the mathematical model,the corresponding numerical model is analyzed,parameter optimization is carried out by means of parameter scanning,and the rule between these key parameters and detection results is analyzed and summarized in the numerical model.Thirdly,the overall scheme of AC electromagnetic detection device is designed,and the signal excitation device is designed in consideration of energy management and device miniaturization.The corresponding physical device is designed,including signal generation module,power amplifier module,signal conversion module,locking amplifier module and so on.The experimental device is set up for experimental verification of the tested part,parameter optimization of the detection coil is initialized,visual presentation of the detection data is made,and the relevant laws of defect size are preliminarily analyzed based on the data.Fourthly,this issue proposed a defect size inversion algorithm based on EMD-RF.The characteristic of this method is that it achieves highly adaptive de-noising on the basis of data inversion and improves the accuracy of inversion.Firstly,EMD algorithm is used to process the original data,analyze the components of the data and extract the key information.The size inversion model based on RF algorithm is constructed,and the processed data and the key information carried by the algorithm are taken as the training set and test set of the model,and the defect size is analyzed by inversion,and the corresponding conclusion is given.