The Lightweight Design Technology Of Some Typical Automobile Parts

While automobile brings people’s life large convenience, it also produces huge environmental pollution. A lot of researches show that vehicle’s energy-saving and emission reduction can be realized through the lightweight design, which has been widely used in the developed countries, but in domestic it still seldom used in the automotive industry. With the progress of structural optimization techniques, the popularity of new materials, and the development of processing technology, it has become reality to improve the vehicle’s performance and reduce its emissions through lightweight design. And the lightweight technology is in urgent needed by the domestic auto industry to reduce the pollution.In this paper, the automotive lightweight design was set as the theme, the typical automobile parts, like engine hood and hooks, were chosen as the research object, and the finite element analysis and lightweight design were carried out on these parts. The main work content includes:1) The vehicle lightweight research’s background and significance and its research status and development trend at home and abroad were reviewed. The method of vehicle lightweight was introduced, include new materials, structure optimization and the corresponding processing technic.2) An original engine cover was analyzed by finite element method. The 3D model of cover was set up in CATIA, its finite element grids were generated and assembled in HyperMesh; the corresponding solving condition was formulated, according to the requirements of its working environment and mechanical properties. Finally, the cover’s mechanical performances under various conditions were obtained by finite element analysis.3) Two kinds of schemes were adopted for lightweight design of automobile engine cover. Scheme one using the method of combining topology optimization and shape optimization to design an aluminum alloy cover; scheme two using the method of combining shape optimization and size optimization to design a sandwich cover. The results showed that both optimization schemes can satisfy the mechanical properties of the cover, and can also make weight loss 48% and 18% respectively.4) The performances of vibration attenuation and sound insulation of the three engine covers were analyzed and compared. The numerical acoustic analysis method was introduced; the covers’ acoustic finite element model were established in Virtual.Lab, and their sound transmission loss was obtained through acoustic finite element analysis. The result show that, the sound transmission loss of scheme one aluminum alloy cover decreased compared with the original cover; and the scheme two aluminum foam sandwich cover’s increased for both low frequency and high frequency noise.5) The magnesium alloy wheel was dynamically analyzed and then lightweight designed. The wheel model was established and its dynamic bending and rolling fatigue tests were simulated and analyzed by ANSYS Workbench. To gain more reasonable stress distribution of wheel, the method that first determined mass and designing structure then comparing stress was proposed, and it was used to optimize spokes and bolt holes’ number of wheel. Then the wheel’s structure parameter was optimized by combining response surface method, Latin hypercube sampling and multi objective genetic algorithm. The optimized wheel reduced 37% of its weight, and can also achieve the dynamic fatigue performance.