Research Of Rubber Fatigue Optimization Under Multiaxial Loading

With the raising development of economic level, the demand of security and comfort for travel tools is higher and higher. Therefore, the development of rubber elastic damping component is fast in cars, rail vehicles. The bushing is common damping component in bogie, and it is very complex in operation and fatigue damage under multi-axial loading. It is very important to understand its loading-bearing and the reason of fatigue. Due to the characteristics of large deformation of rubber, there is no mature theory of estimation for fatigue life. There are two main types of rubber fatigue prediction methods commonly used at home and abroad:a crack nucleation method for investigating the crack generation process and a crack growth method for simulating the process of crack initiation. Based on the finite element analysis, this paper uses the strain as input and combines crack extension test which uses crack energy density as the basis. The following items are mainly researched:(1) This paper describes fatigue damage affecting factors of rubber elastic component and rubber fatigue failure mechanism. Rubber material possesses large deformation, super elasticity, incompressibility and recoverability, therefore, it is used widely. However, there has not formed a mature theory. This paper introduces the domestic and foreign prediction methods for fatigue life of rubber under multi-axial loading.(2) A rubber multi-axial fatigue life prediction method on the basis of CED theory is proposed by using the FEA software based on an Abaqus & Endurica platform, and prediction process is specifically introduced. This method has the advantages of not only being capable of effectively predicting the fatigue life of rubber structure under multi-axial loading, but also forecasting potential crack initiation area, and can characterize critical surface.(3) This paper uses Isight & ABAQUS to carry out the simulation optimization for three kinds of rubber material. Results show that the rubber formulation and production technology is related to the performance of the rubber. With the increasing of rubber hardness, the degree of sinking is more and more deep and the body side is more and more slow under the requirement of static stiffness.(4) This paper proposes a method which combines cracking energy density and fatigue optimization. This method not only can predict the fatigue life of rubber, but can optimize the structure, so it provides effective guidance.This paper finishes the optimization and fatigue prediction of bushing. The theory provides a way for exploitation of rubber elastic element, and shortens the development cycle of bushing. In engineering this optimization method reduces the experiment cycle and costs.