Locomotive Cooling Steel Structure Strength Analysis And Parametric Optimization Based On Finite Element Methods

With the comprehensive development of diesel locomotive and the improvement of running speed,the design of locomotive cooling system get more attention,the basic is to ensure the strength of structure in order to make locomotive’s operation safe and reliable.The steel structure connects radiator on top,engine room on side and bogie on bottom.it is very important to research strength and dynamic characteristics for locomotive running security and improvement of the steel structure.This paper briefly summarizes locomotive development history and research status of relevant theory and theoretical basis,using UG establish the steel structure 3d model and finite element model by HyperMesh,defining boundary conditions based on the cooling whole actual structure.According to the standard of TB/T1335-1335,computing and analyzing static strength loads and conditions of bolt junction between steel structure and locomotive base plate,eventually clear stress distribution and the weakest part of the steel structure and according to the results to complete strength check.Results show that the steel structure maximum equivalent stress is 467.868 MPa which happens in contact point between washer and nut that satisfy the requirement of the bolt performance level;Under longitudinal and longitudinal with vertical combination conditions,the maximum equivalent stress of the edge of corner in steel structure hollow support plate is higher than 261.364 MPa that is material allowable stress,which did not meet the requirements of strength;Under the condition of horizontal and vertical,the maximum equivalent stress of the structure is lower than the allowable stress of material.According to TB 3058-2002 standard,three fatigue load cases are defined to calculate and analyze,the principal stress range of the steel structure is no less than the allowable values.Extracting the structure’s first principal stress and calculating structural cumulative fatigue damage sum which is far less than 1 that Miner rule under each case based on BS7608-1993 standard and Miner theory,so,the steel structure occurs to fatigue damage is impossible.Structural optimization adopts parametric optimization for avoiding wasting time for secondary modeling.Combined HyperMesh with Design Explorer module of Workbench can be intuitive show the corresponding relationship between design variables and target parameters.Optimizing related element size to make the maximum equivalent stress under longitudinal and longitudinal with vertical combination cases is less than 261.364 MPa that ensures the safety of steel structure practical application.In order to research structural dynamic characteristics,this paper has done freedom modal analysis on optimized structure based on Block Lanczos method,it assures the steel structure’s natural frequency and vibrationmode that needs to be referenced for designing and analyzing connected structure or bogie and car body.