Parameter Calibration Of Wet Mediaand Contact Model Analysis

Mass finishing technology as a typical free-abrasives surface finishing method,with the advantages of low cost,simple operation,high efficiency and environmental protection,is widely used in aviation,automotive,electronics and other manufacturing fields.Discrete element method(DEM)can effectively analyze the mass finishing process.Media as the main processing medium,its contact parameters have a great influence on the analysis results,and the selection of contact model also has a large impact.At present,the discrete element is used to study the mass finishing process.The selected contact model is mainly Hertz-Mindin(no slip)non-adhesive,no other contact model is selected to study the adaptability to mass finishing.Therefore,the application of the contact model lacks the systematic analysis and experimental exploration.In view of the parameters of the dry media,the parameters of the wet media are calibrated,and then the parameters of the wet media are applied through the EDEM.The different contact models were selected to simulate the spindle mass finishing process,and finally verified by the dynamic force sensor test platform.The main researchcontents of this paper are as follows:1.Based on "Hertz-Mindin(no slip)" non-adhesive contact model to calibrate the parameters of the dry model,select the "Hertz-Mindlin with JKR" contact model to calibrate the wet model parameters,using injection combine images analytical method to obtain the angle of repose of media,and the angle of repose is used as the evaluation index.Firstly,Plackett-Burman test method is used to screen out parameters that have significant influence on repose angle of media,and then the optimal range of the significant parameters is determined by the steepest climbing test,finally,the response surface method Box-Behnken test is used to find the optimal combination of parameters.The simulation analysis is performed by using the optimal parameter combination,the relative error is 0.6% compared with the experimental repose angle,it is feasible to use this method to calibrate the discrete physical parameters of wet model.2.The "Hertz-Mindin(no slip)" non-adhesive contact model and the "Hertz-Mindlin with JKR" contact model were selected to simulate the force of the workpiece under the two contact models by changing the different processing positions and drum speeds.The same processing position and drum speed were selected to simulated.The dynamic force sensor test platform was used to test the force of wet model on the workpiece,and the simulation results and experimental results were statistically analyzed.Analyze the influence trend and degree of force of the dry and wet model on the workpiece under different processing positions and drum speeds.The fitting contrast analysis of differentparameters were carried out to establish the relationship between the processing position and speed of the workpiece,and fitting analysis under different parameters.3.The experimental results of dry and wet media under different processing positions and drum speeds are compared with the simulation results.The results show that the force of the dry and wet media on the workpiece under the test is basically the same as that under the two models selected under the simulation.It is verified that the EDEM contact model can be used to predict the influence of parameters on the processing effect.However,the difference between the test and the simulation results is large,and it is impossible to guide the selection of parameters in actual machining.In this paper,the "Hertz-Mindin(no slip)" non-adhesive contact model and the "Hertz-Mindlin with JKR" contact model considering the adhesion force in the EDEM discrete element simulation software are applied to analyze and research the force of the workpiece by dry and wet media.and the dynamic force sensor is used to test the force of the workpiece by the dry and wet media,thus perfecting the application of the theoretical model of the mass finishing processing,and expanding the gap in the field of discrete element contact model research in mass finishing processing.