Study On Optimization Of Carbody Of Low Floor LRV By FEA

As a new transit pattern, the main features of the light rail transit are distance between light rail transit stations rather short, frequent start and brake. In order to get the higher starting and braking acceleration, the light rail vehicle needs to reduce its weight as much as possible and uses the optimized structure. As the principle part of a vehicle, body is one of the main object of optimization. It becomes an important research task to solve the contradiction of not only meeting the performance demand, but also ensuring the curb weight lightest in the design and manufacturing of the light rail vehicle body. To the body of model Q6W-2 light rail vehicle, which is made by Xiangtan electrical machine Co Ltd, a series of research work were done. To the light rail vehicle body, the author carried out FEM analysis both in strength analysis and in stiffness analysis, and did static strength test. The calculation value is consistence with the measure value. It is proved correct to establish the FEM model, simulate the boundary condition and select the solver. Based on the FEM analysis and the static strength test, the author selected the appropriate initial body structure and optimization method, and established optimization mathematic model of the continuous variable, with the curb weight as the object function and stress as the boundary condition. Also the author carried out the optimization analysis of continuous variables on car body and obtained the optimization result with ANSYS optimizing tools. For the reason that the optimization solution of continuous variables can not apply to the engineering practice, the author put forward a new optimization method of discrete variables aiming at improving the characteristics of light rail vehicle body. This method is that the optimization mathematic model of the discrete variable is established based on the optimization result of the continuous variable, after the multiple incongruent results are rejected according to special algorithm, the final solutions are obtained from the small quantity remnant solutions by using the FEM. With part B of the body as an example, this paper did optimization analysis by using the above method. After the discrete variable optimization, the FEM analysis of the new body remodeling shows that, except some rejected special position (such as restrained point), the equivalent stresses of the body are all within the permissive stress, and the stress distribution tends to more even. The weight of the body reduces about 8%. And the optimized body has already been used in the engineering practice at the present time.