Research On The Structural Design Optimization Method For Aluminum Frame-type Truck Cab

With the rapid development of automobile industry in China, car ownership continues to grow rapidly. The environmental problems caused by vehicle emissions are increasingly serious. Lightweight, especially the light weight of the body, is the first choice to control emission, which is an effective means to improve the performance of the vehicle indirectly. Structure optimization is the basis of lightweight design, in the best shape structure supported by appropriate materials, each part of the material can play the maximum effectiveness, improve material utilization, reduce vehicle weight and reach the discharge standard.This thesis puts forward the necessity of structural optimization of frame type cab based on the research of structural modeling and optimization algorithms of vehicle body in recent years by domestic and foreign scholars, as well as the existing problems. Secondly, the thesis establish BIW finite element model of truck cab,using modular modeling method based on the statics analysis theory, selecting acceleration and steering condition, braking, vertical turbulence conditions, bending stiffness analysis cases, torsional stiffness analysis cases and cab free modal analysis cases, of driving the basic properties of the body in white was evaluated. According to the strength, stiffness and vibration characteristic parameters, the reference value is provided for the constraint conditions of the structural optimization. Then, Based on the variable density method for topology optimization theory, select the vehicle in the process of the typical working conditions, Using AHP to determine the weight coefficient, set the appropriate design variables and constraint functions, joining into the manufacturing process constraint, the original cab topology optimization analysis. According to the results of the analysis, the basic dimensions of the underlying sample cab based construction of frame type truck driving room basic shape and structure by using 3D drawing software.Finally, based on the frame type freight car driving room basic shape and structure performance analysis, constraint conditions are selected according to the results of the analysis and reference the basic performance parameters of the original cab. A final frame type cab structure is determined through the frame type cab structure of beam section size optimization. The final structure basic performance and the original cab were compared, and model is verified with respect to the traditional sheet metal structure in the quality and performance of the superiority,based on GB 26512-2011 regulations for roof strength and confining strength simulation analysis. This thesis preliminary explores a comprehensive solution of establishing finite element model and provide experience for reference for all types of finite element analysis calculation.Aluminum alloy frame type cab not only has a great advantage in terms of safety, but good vibration characteristics. Quality structure significantly reduced in little difference compared with the basic properties of the original cab based, reflecting the superiority of application of the finite element analysis method in automobile body design.