Lightweight Design Of A Commercial Vehicle’s Cab Based On Relative Sensitivity And Comprehensive Optimization

With the advent of the energy crisis and environmental issues, the lightweight design of cars has become an important factor to consider in the designing process. For the commercial vehicles, it can not only reduce fuel consumption and harmful emissions, but also increase the car’s capacity for loading, which could improve the transportation efficiency. As an important part of the vehicle, the cab is the main event space for the driver and it is very important to optimize the structure of the cab for improving its performance.The thesis focuses on the commercial vehicle’s cab to optimize its structure, which achieves the reduction of the cab’s total mass without declining the performance. For the commercial cab or other complex structures’lightweight design, combined with the strategy of comprehensive optimizationthe, this thesis will carry out a plan to achieve a comprehensive design for the commercial vehicle’s cab, which contains multi-use performance constraints in working conditions and more components’participation, in the development and design stage. First it is essential to assessing the overall performance of the cell structure by building its finite element model and analyzing the dynamic and static characteristic on different working conditions, which includes bending、twisting or free state.Cab is a large structure made of many parts. To avoid blind optimization and improve design efficiency, make a sensitivity analysis for the structure before optimizing the model, which can quantify the contribution of each component to the overall performance of cab. For sensitivity analysis for the cab, make the bending stiffness, torsional stiffness, the primary frequency and total mass constraints; the thickness of cab’s parts design variables. Further, on the basis of sensitivity analysis, the thesis proposes the use of the Evaluation Methods on relative sensitivity and average relative sensitivity to select optimization parts, which can simplify the selection process of variables. Then, because the optimization object has so many variables and constraints, for shortening the optimization time, the thesis puts forward a simple and efficient design, which includes three schemes, namely the light weight program, the highly performance program and the integrated program. These schemes are considering all constraints but having different emphases. At last, besides comparing the performance of optimized structures, take use of Lightweight coefficient to evaluate optimization results from different design schemes. The results show that the integrated program quickly realizes the lightweight goal for the cab. Finally, verify the optimized cab passive safety performance according to the technical requirements of ECE R29-02.The final optimization results show that the commercial vehicle’s cab achieve losing weight by 24.9kg, accounting for 7.40 percent of the cab’s total mass, in the case of meeting performance.