Research On Lightweight Design Of Semi Trailer Support Bridge

According to the current domestic demand for lightweight semi-trailer,lightweight design of semi-trailer support bridge is carried out in this paper.According to the weight reduction idea of the first part and then the whole,the lightweight design method of light material,structure optimization and shape optimization is adopted.According to the working environment and working state,different weight reduction schemes are selected for the components of the supporting bridge,including axle,disc brake and wheel hub,to achieve the lightweight design of each part.According to the optimized model,the sample was manufactured and the bench test was carried out.The main research work is as follows:1.The working conditions of the trailer bearing bridge are systematically studied,and two working conditions are summarized.Ansys Workbench(AW)software was used to analyze the transient mechanics of the axle under two working conditions.According to the transient analysis results,Adams was used to carry out dynamic simulation of the axle to get the bending moment and force curve of the axle.According to the bending moment and force curve,Ansys Workbench was used to carry out static analysis of the axle.According to the results of static analysis nephogram,the dangerous section of the axle is determined to be the center of the axle near the leaf spring seat and the end of the circular section.AW optimization module was used to do secondary response surface optimization.The candidate dimensions of axle optimization were obtained through response surface optimization,and the optimal solution was selected to conduct three-dimensional modeling of axle again.Fatigue analysis and strength calculation are carried out to determine whether the calculation results meet the design criteria.2.According to the two working conditions of the bearing bridge,the disc brake is generally studied,and the disc brake is divided into two main parts-brake disc and brake caliper.The brake disc is made of light material.The linear static analysis of the light material brake disc is carried out by using ANSYS Workbench software.The stress distribution of the brake disc is obtained according to the analysis nephogram results.Brake calipers are divided into three main parts--main caliper body,vice caliper body and bracket.ANSYS Workbench software is used for linear static analysis of the main parts of brake caliper,and the stress distribution and dangerous section position of the parts are obtained according to the deformation and stress nephogram.Mass and deformation are the main output parameters.The response surface optimization was carried out with the basic size as the input parameter.The fitting points were screened to obtain the optimal candidate points,and the 3D model was reconstructed according to the optimal candidate points.3.Based on the structure analysis of the hub,according to the two working conditions of the supporting bridge,the hub in the static load,impact,braking three conditions of the constraint load.The hub force and bending moment amplitude are obtained through dynamic simulation in impact condition and braking condition.The geometric post-processing method of Workbench Space Claim is adopted to carry out geometric post-processing on the main dimension parameters of the hub.The linear static analysis of the hub under static,impact and braking conditions is carried out by ANSYS Workbench software,and the Kringing mathematical model is built according to the stress and deformation netogram obtained from the analysis.The hub size sensitivity map is obtained by using CCD algorithm.The impact stress nephogram was obtained by transient mechanics analysis of hub braking process.Based on the fatigue analysis of hub brake load,the hub fatigue safety factor diagram is obtained.Topology optimization was carried out on the basis of hub sensitivity graph,simulation motion curve and fatigue safety factor graph,and the new hub was obtained after topology optimization4.The modal analysis is carried out to verify the reasonableness of the lightweight support bridge.The prototype of the supporting bridge was manufactured and the bench tests were carried out.Three bench test items,vertical bending stiffness,vertical bending static strength and vertical bending fatigue life,were carried out on the axle of the supporting axle to compare whether the test results meet the standards of JT/T 475-2020 "Trailer Axle" and JT/T 1178.2-2019 "Safety Technical Conditions for Trucks in Operation Part II: Tractive Vehicles and Trailers".Torsional fatigue bench test is carried out on brake calipers to compare whether the test results are in accordance with Article 6.7 of GB/T31970-2015 "Automotive Pneumatic Brake calipers Assembly Performance Requirements and Bench Test Methods".Brake disc run-in,crack bench test,compare the test results are in line with GB/T 34422-2017 "Automotive brake disc" on wheel hub durability fatigue bench test,compare the test results are in line with JT/T475-2020 "trailer axle" wheel test standardThe weight of the lightweight semi-trailer support bridge is reduced by 30%compared with the original structure,from 204.8Kg to 141.38 kg before the lightweight.