Bushing Stiffness Characteristics And Structure Parameters Optimization Based On Handling And Stability

Rubber bushing is a comparatively important part in chassis. Its stiffness characteristics greatly affect the K&C characteristics of suspension system, and then it has a very important effect on the handling and stability of a vehicle. What decides the stiffness characteristics of the bushing, besides the materials of the bushing, is bushing structure parameters. On the basis of the construction project about Chinese high level on independent and innovation ability, this paper researches how the handling and stability of a vehicle is affected by the stiffness characteristics of the bushing; and to achieve the particular stiffness characteristics, this paper carries on a design on the rubber bushing structure parameters. This paper is mainly about these two aspects.At first, this paper builds the ADAMS Model of vehicle. To make it more accurate, there is corresponding verification after every subsystem model has been build, ensuring the precision of every subsystem model. Then the front and rear suspension, steering system and tire model are assembled into a full vehicle model, and apply the test data of a real car to verify the accuracy of the model. The main reason of optimizing the Stiffness characteristics of the bushing is to make vehicle have better handling and stability. Hence, the paper then states the objective evaluation system about the handling and stability, which based on the total variance method and is put forward by Academician Konghui Guo. This system takes two test conditions of snakelike and double lane change into consideration. It's evaluation indexes involve precision of tracking, the risk of overturn, road feel etc, which can evaluate quite well the handling and stability of vehicle. Therefore, this paper applies this system to evaluate the handling and stability of vehicle.There are many bushings on chassis. If we do adjustment to every bushing, the workload will be quite heavy. In addition, some bushings have less effect on the handling and stability of vehicle. To avoid the blindness of optimization, this paper firstly analyses the sensitivity, finding the stiffness characteristics of the bushing, which have great effect on the handling and stability of the vehicle. And then optimize them. In this case, we can guarantee the optimization result, and at the same time, reduce the workload largely. On the basis of analyse on sentivity, optimize the stiffness characteristics of the bushing, applying the co-simulation of iSIGHT and ADAMS. The goal of optimization is to make the handling and stability of vehicle as good as possible. Optimization method adopts the Multi-Island GA (Multi-Island Genetic Algorithm), which can search the optimal solution more easily and quickly. Not only does it have high efficiency in searching optimal solution, but also avoids effectively sinking into the partial optimal solution. Through contrasting the lateral acceleration and other corresponding parameters under the conditions of snakelike and double lane change before and after the optimizing, it is clearly that the handling and stability has been improved definitely.To optimize the bushing structure parameters, this paper then builds the finite element model of rubber bushing with ABAQUS software. Materials apply Mooney-Rivlin model whose parameters are obtained from the data of the bushing test on Stiffness characteristics. The steel jacket of the inside and outside tube of the bushings is replaced by the rigid body, and the vulcanization connection in actual structure is simulated by the tie connection. Loading along axial and radial direction on the built model, we can get the stiffness characteristics in different direction of the bushing. Contrasting with the test results, we can verify the precision of the model. And it is proved that the method of building model is feasible. Next, using the co-simulation of the iSIGHT and ABAQUS, optimize the bushing structure parameters. The goal of the optimization is to achieve the particular optimized stiffness characteristics. The method of optimization applies NSGA-II (Non-dominated Sorting Genetic Algorithm), and at last, choose a solution from the Pareto set as the optimal solution.About the method of optimization, this paper tries to use the co-simulation of the ADAMS and iSIGHT and the co-simulation of the ABAQUS and iSIGHT as a optimization platform. Through contrasting the results before and after optimization, it is proved that the optimization method is feasible. This paper researches the process of the optimization on the rubber bushing structure, which can provide reference for engineering application.