Research On Lightweight Optimization Method Of Truck Body-in-White Based On Sensitivity Analysis

Research shows that the curb weight of a vehicle is directly proportional to fuel consumption and exhaust gas.The lower the curb weight,the lower the fuel consumption and exhaust gas.It can be seen that the reduction in the quality of the vehicle can improve the performance of the vehicle.The cab body-in-white occupies 20% to 30% of the vehicle quality,and the cab body-in-white is mostly composed of sheet metal parts.Therefore,there is a large room for improvement in lightweight optimization and easy optimization.At the same time,the body-in-white greatly affects the performance of the vehicle,such as safety,NVH,lightweight,handling,and comfort.In this paper,combined with the actual project of the enterprise,a lightweight design of a domestic truck cab body-in-white is carried out.The specific content is as follows:1.First introduce the current research status of implicit parameterized modeling and common research methods,and then use SFE Concept software to establish five implicit parameterized models of the cab side wall,roof,floor,front wall,and rear wall.,The left side model of the truck cab body-in-white is established through the mapping relationship,and finally the cab body-in-white model is mirrored.Determine the initial variables according to the characteristics of different parts and actual experience,and complete the establishment of the white body model of the cab.Calculate the low-order bending and torsion modes and bending and torsional stiffness of the model,and compare them with the experimental data of the bending and torsion modes and stiffness of the white body provided by the company to confirm the accuracy and usability of the model.2.For the built model and the entered variables,through sensitivity analysis,calculate the derivative of the main performance parameters such as bending torsional stiffness,low-order mode and mass with respect to each variable,obtain the sensitivity coefficient,and obtain the variables for preliminary analysis.Analysis and comparison of the currently used sensitivity analysis methods,combined with engineering practice and the actual needs of the project,select the fuzzy gray cluster analysis method for analysis.Based on the inputted initial variables such as structure and thickness,the variables were screened,and24 design variables were screened out,including 20 thickness variables,4 shape and position variables.3.Optimize the design of the 24 selected design variables.Through experimental design and its data,build an approximate model,based on the original values of the body’s bending stiffness,torsion stiffness,first-order torsion mode,and first-order bending mode,and set the basic value to not change more than 5% as a constraint,The lightest quality is optimized for the goal.The optimization results show that the bending stiffness and torsional stiffness of the body-in-white are reduced by no more than 2%,the first-order bending and torsion mode frequencies are improved by 3.5% and 4.2%,respectively,and the body-in-white mass of the truck cab is reduced from 297.2kg in the initial model.275.2kg,the weight reduction rate reaches 7.4%.A good lightweight effect has been achieved.