| Wheel is one of the most important parts in the driving system of automobile, it transferred the forward impelling force of automobile, and its performance affects the security and reliability of automobile. Furthermore, the wheel also plays an important role in the automobile's appearance. Magnesium alloy has been applied wildly in recent years, because it has many advantages, such as small proportion, high-strength, good-looking and easy to be recycled. The magnesium alloy wheel of automobile can effectively reduce energy consumption, vibration and noise; meanwhile, it can improve the comfort and safety of automobile.However, the most methods of fatigue life prediction and optimization design were used to the steel wheel and aluminum alloy wheel, the fatigue behaviors of magnesium alloy is different with them. Therefore, it is very important to search the methods of fatigue life prediction and optimization design for magnesium alloy wheel to achieve the replacement of magnesium alloy and promote its application.According to the industrial design theory, the methods and skills of model design are applied to the design of magnesium alloy wheel. The model was established in accordance with the national rim standard, using UG NX software with the aesthetic principles. The fatigue of magnesium alloy wheel is characterized by mechanical variable amplitude fatigue in according with weight of automobile, the impulsive load and vibration load when it is driving over rough terrain. Meanwhile, for security reasons, the nominal stress of wheel is less than the stress of yield strength; it is characterized by a high-cycle fatigue. Therefore, magnesium alloy wheel is characterized by mechanical high cycle variable amplitude fatigue.The ultimate aim of fatigue analysis for the magnesium alloy wheel is to predict the fatigue life. According to characteristic of it is the mechanical high cycle variable amplitude fatigue and the fatigue experimental requirement was regulated the Chinese automotive industry standard in performance requirement and experimental methods of the automotive light-alloy wheel to determine the boundary conditions and imposed loads, the stress was been calculated by using ANSYS software. Nominal stress method was been adopted to predict the fatigue life of magnesium alloy wheel by the stress of peril point. The results showed that the fatigue life of magnesium alloy wheel can meet the requirement of automobile, but the weight loss effect of wheel is not obvious due to the great fatigue strength margin, there is necessity to make further optimization. Therefore, magnesium alloy wheel was optimized by ANSYS based on taking the wheel weight for the object function, taking the thickness of rim and spoke for the design variables, taking the bending fatigue strength of magnesium alloy for restrictive conditions. The results indicated that fatigue life can still meet the requirements whereas the weight of the magnesium alloy wheel to reduce by 22%.
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