Grinding Temperature Research Of Aerospace Parts Based On Epitrochoid Heat Source Model And Software Realization

As a finishing process,grinding can well ensure the machining accuracy of aerospace shaft parts to reach the expected criteria.Nevertheless,excessive energy that transfers into the workpiece during grinding process will increase the workpiece temperature,and lead to thermal deformation,grinding burn and so on.Thus,it is necessary to carry out the thermal analysis of grinding process.Neglecting the change of heat source profiles with process parameters,the previous researches on the grinding thermal analysis focused mainly on fixed heat source profile using the moving heat source method.And there are few studies on the optimization of the grinding process for the aerospace shaft parts with the grinding temperature considered.Besides,there exist only few softwares specifically developed for grinding process analysis of such parts.This thesis is funded by the project(No.JG2017092)and establishes a new epitrochoid heat source model that includes influences of the process parameters and the adaptive heat source profiles.The change laws of the process parameters are revealed.Then,the grinding process optimization is studied based on the new model,and a related analysis software is developed.The main work of this thesis is as follows:First,a new epitrochoid heat source model with adaptive heat source profile is established and further compared with some traditional heat source models.To this end,the workpiece temperature field is solved using MATLAB programming in combination with the moving heat source method,and the numerical results are compared with the experimental grinding temperature in order to verify the new heat source model.The numerical results show that,compared with the traditional uniform,right-triangular and quadratic heat sources,the proposed heat source has better temperature prediction capability due to its adaptive heat source profile.Furthermore,the new epitrochoid heat source’s profile change law,and the temperature distribution of the aerospace workpiece under the epitrochoid heat source with different process parameters are studied.To this end,the variation laws of undeformed chips thickness with different process parameters are studied.The numerical results show that a greater grinding wheel linear velocity,a greater grinding depth,or a smaller workpiece linear velocity will lead to an increment of the maximum temperature rise in the grinding contact zone.Then,a generalized radial basis neural network and genetic algorithm are used to carry out a multi-objective optimization research on the aerospace workpiece grinding process.In the optimization,the grinding wheel linear velocity,workpiece linear velocity,and grinding depth are considered as independent variables,and the minimums of the grinding temperature and surface roughness along with the maximum of the material specific removal rate are the optimization objectives.The multi-objective genetic algorithm and weighted sum method are used to obtain the optimal combination of process parameters that realizes the comprehensive machining target of the workpiece.Finally,the analysis software for grinding process of common areospace materials is developed.The software is based on VB,FORTRAN and MATLAB hybrid programming,which can analyze the lubrication and temperature of the grinding process according to the process parameters under the selected type of grinding wheel,workpiece and grinding fluid.It can also give the calculation results of the film pressure,thickness and temperature distribution of the grinding fluid in the grinding contact area.The grinding database has been developed so that process formulators can quickly add,delete,and modify the contents of the database as needed,providing a benificial reference for the process development.