Rubust Optimization Of Hot Forging Process Of Thin-walled Gear Ring Based On SVM-IMPSO Model

The thin-walled gear ring is an indispensable part of the transmission structure.Due to its complex geometry,the thin-walled gear ring during deformation prone to occur many defects like underfilling of tooth,crack,fold and low material utilization.Thus,the representative synchronizer ring made by high-strength wear-resistant brass was chosen to investigate the mechanism of defects during deformation and the method to improve deformation process.The research was based on consists of thermal physics simulation experiment,finite element simulation method,statistical learning theory and intelligent optimization algorithm.According to the research results,a robust optimization for the forging process of thin-walled gear ring was proposed.The main conclusions are list as follows:(1)The Arrhennius type constitutive model considering compensation of strain was established based on the true strain-stress data which obtained from the single-pass isothermal compression test.Through the analysis of the accuracy of the model and the analysis of the error source,a revised model considering the influence of the deformation conditions on the parameters was proposed.The accuracy of the revised model is improved.It can accurately reflect the flow behavior of the manganese brass at high temperatures.(2)The constitutive model of flow behavior at high temperature for manganese brass was integrated with the finite element model by secondary development.Then the finite element analysis model of the hot forging process for thin-walled gear ring was established.After completed the analysis of deformation process,the original process was improved by the preform design through the method of changing the distribution of blank volume and the material flow pattern.The thin-walled gear ring were formed well when the flow pattern of the metal was changed according to the result.The tooth-shaped part is filled completely,the damage value of the side wall and the spline are reduced,and the material utilization rate was also improved.(3)Considering the impact of process factors on deformation quality,a robust design method for thin-walled gear ring deformation process based on Support Vector Machine and Improved Particle Swarm Optimization algorithm was proposed.By applying this method,a high precision fitting function for deformation process parameters and quality evaluation index was constructed.(4)The improved particle swarm optimization algorithm was used to optimize the multi-objective optimization of the process parameters.Combined with the fuzzy theory,the extreme solutions and optimal compromise solutions of the three objective functions are given respectively.The numerical sim ulation results show that the forming quality of thin-walled gear ring was improved obviously when the optimal combination of process parameters was adopted.The robust optimization design method proposed in this paper is highly effective and feasible in the optimization design of hot forging forming process of thin-walled gear ring,which can provide reference for the formulation and optimization of the forming process for similar parts.