Application Of Nb-Bearing High Strength Steel In Lightweight Design Of Racing Car Frame

The frame of racing car which is closely related to the performance of a racing car plays the key role of support,full vehicle bearing and protection driver.Due to the low rigidity of the front partition system and the overall excess of the strength,the floor vibrate violently when the racing car is at the idling speed.This also shows poor performance of a vehicle in comfort,traction ability and fuel economy.In order to solve this problem,improve the modal performance and reduce the weight of the racing car's frame,the lightweight design method of combining material and structure is studied in this paper.Based on Nb-bearing high strength steel,using the method of structural optimization design can effectively realize energy saving and emission reduction,while improving the performance of a racing car,which is of great value in engineering application and academic research.The main contents of this study include:(1)the test and selection of the basic properties of Nb-bearing high strength steel,including the effect of niobium on the integrated performance of steel,performance test of Nb-bearing high strength steel,selection of steel,modeling of Nb-bearing high strength steel,and simulation of the impact resistance.(2)The finite element model of racing car frame is established,including the establishment of the original model,the improvement as well as the finite element model before processing.(3)the free modal analysis of racing car frame before and after the improvement,the frequency analysis of engine in idling and normal driving conditions,the vibration analysis of model before and after improvement,by using first six order free vibration models of the racing car frame,find out the cause of the racing car floor vibration and validation of the frame mode.(4)The static characteristics of the racing car frame model are analyzed.The static characteristic analysis consists of many cases,and the maximum stress of the racing car frame under the five working conditions is obtained by the finite element method,and the strength margin of the size is obtained.(5)The security check of the racing car frame model before and after improvement including the security check of the important parts and the maximum displacement of the racing frame under the five working conditions is obtained by the finite element method.(6)The size optimization model based on multi-variable,multi-constrained and multi-operating conditions was established,and the results of size optimization were calculated by software Opti Strust.The size optimization results were compared with steel 4130.(7)The normalization of size optimization results: the four results are analyzed,evaluated and selected by the four generalization methods.Based on Nb-bearing high strength steel,the normalization of size optimization results of the racing car frame is completed.Through the above research,the frequency of the first two free vibration of the racing frame is increased by 10.6Hz and 6.8Hz respectively,and the quality is reduced by 15.4%,which solves the problem of low rigidity and overall excess strength of the original front C lapboard structure.The application of Nb-bearing high strength steel in lightweight design of racing car frame is completed.The results in this research contribute to promote the application the Nb-bearing high strength steel in automobile industry,help to improve the design method of truss structure and establish systematic method of the lightweight design,which is of great significance to mode,strength,stiffness analysis and the application of new materials in automobile industry.