The Study On The Method Of Structural Optimization On Heavy Truck Cab

With the rapid development of computer and numerical value method,some engineer problems whatever are simple or complicated can easily be resolved by discrete numerical methods and computers. Finite Element Method (FEM) is not only one important numerical value method,but also supplies a platform for structure analysis.This paper is a basic study for structure optimization design. The paper presents some basic ideas, applications and development in automobile lightweight,CAE analysis and optimization filed. Then the simulation model of the cab is built and some research work about mode frequency and stiffness of the cab is done. A combination of size optimization and topology optimization is been firstly used in auto body structure optimization. The target of optimization is built to increase stiffness of the cab and decrease the weight of the cab. Then Spot-weld Layout Optimization for Body Stiffness by Topology Optimization is done. At last, a model for analysis is built and the structure optimization results are used in frame optimization. The main research works are focused in the following aspects:1. Modeling of the heavy-truck cab. The model of light-truck cab is built and key points of modeling are pointed out. Using the finite element analysis software of HyperWorks, carried on the FEM Preprocessing,mesh generation,the spot link for the vehicle cab, and has established the complete vehicle cab finite element model, has given the theory and the actual instruction for the similar vehicle type's finite element modeling. These will be helpful for modeling of the similar analysis.2. Mode shape and stiffness analysis. The mode frequency and the stiffness of the cab is computed by the FE analysis software. The simulation results of the mode frequency verify the Correctness of this CAE model, and the stiffness of the cab is not enough. The Von Mises stress of the four corners in the front is close to the yield limit. The target of optimization is built to increase stiffness of the cab. 3. Optimization of the structural parts thickness by Topology Optimization and Size Optimization. The target of optimization is built to increase stiffness of the cab and decrease the weight of cab. Firstly, the best load path to increase the torsion stiffness is point out by Topology Optimization analysis. Secondly, the thickness of the structural parts determined by the result of Topology Optimization is optimized by Size Optimization. At last we get three optimization schemes. Every scheme has special emphasis on different aspect.4. Then Spot-weld Layout Optimization. By Topology Optimization analysis, we delete the Spot-welds that give the minimal contribution to the stiffness. At last we delete 247 Spot-welds. This method has important practical engineering value on the cost saving of the welding line.5 This paper summarizes all the text and prospect the next works about structure optimization design.By Topology Optimization combined with Size Optimization, we can better solve the stiffness problem and realize lightweight. With more and more researches on automobile structure optimization, much more research results will be obtained by using computer technology, theory analysis and experiments.