Research On Lightweight Structure Of Automobile Front End Frame And Optimization Of Injection Molding Process Parameters

With the increasing development of the automobile industry,the emission of fuel vehicle exhaust is also more and more serious to the environment,which requires research and development of new energy products to solve this problem,of which lightweight technology with plastic parts instead of steel parts is a good way.At present,although CAE injection molding technology has been rapidly developed,plastic parts will still have various quality defects in the process of injection molding,for example,volume shrinkage and warpage,etc.,and craft parameters have an essential effect on the quality of injection molding,therefore,by adapting the injection molding craft parameters can improve the injection quality of products.As the study target of this dissertation,the initial finite element model of the upper bracket was set up based on CATIA and Hyper Mesh software,and the topology optimization was carried out by the compromise planning method.Based on Moldflow software,the best gating was researched and injection molding simulated.The orthogonal experiment,gray correlation method,response plane modeling method and genetic algorithm were usaged to tuning the injection molding craft parameters of the upper bracket,and a set of optimal process parameters were gained,and the viability of the design optimization was proved experimentally.This study provides a method for the design of plastic instead of steel products in the automotive industry,and enriches the connotation of parameter optimization of the forming process.The main study of this dissertation are as follows:(1)Completed the lightweight design of the bracket on the front frame of the automobile.Hyper Mesh was usaged to establish a finite element model,single-objective topology optimization was carried out by defining the load of each working condition,the weight value of each working condition was determined,and the mathematical model was established by the compromise planning method for multi-objective topology optimization,and the final part was designed according to the optimization results and combined with the actual injection molding manufacturing.(2)Four gate schemes for brackets on the front frame of the automobile were designed.The optimal gate was determined by the injection moulding process simulation method,and the gating system of the upper bracket was designed and validated.(3)Designed and completed the orthogonal test and moulding craft parameter optimization of the bracket on the front frame of the automobile.Taking the mold temperature,melt temperature,holding pressure and holding time as the level factors,and taking the volume shrinkage rate and warpage as the evaluation index,the 25 compositional craft parameter test of 4 factors and 5 levels was established and completed,and the injection moulding craft simulation was carried out based on the software.The results were analyzed by range and variance,and the multi-objective injection moulding craft parameters were optimized by combining the gray correlation method,and the impact of the best process parameters and factors on the evaluation index was obtained.(4)A second-order response surface model of evaluation indicators was established with key influencing factors,the accuracy of the model was verified by ANOVA and F-value,and the multi-objective optimization of the model was carried out by combining genetic algorithm to obtain optimal injection molding process parameters.(5)The bracket on the front frame of the automobile with the optimized design was tested with physical injection molding and mechanical performances,and the test results were within the qualified range.The feasibility of the mathematical model and injection moulding craft parameter optimization approach established in this study is validated.