Research On Fatigue Life Prediction Method Of Rubber Bushing Under Cyclic Multi-axial Loads

The vehicle’s safety and comfort is improved by wide application of typical rubber elastic damping component such as bushing.. The rubber bushing is used under the long-term impact of dynamic alternative loads, thus being easier to be damaged in fatigue condition. Fatigue damage is the main factor resulting in a decrease of service life of rubber products. Nowadays mature rubber fatigue estimation theory has not been formed domestically yet. 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 methodfor simulating the process of crack initiation. In this article, nucleation life of rubber bushing under multi-axial loading is predicted based on CED and is verified through corresponding fatigue test, by inputting strain history resulting from finite element analysis of product and carrying out rubber material test. The following items are mainly researched:(1) Types and failure modes of rubber elastic element of the railway vehicle bogie is summarized, and fatigue damage affecting factors of rubber elastic component and rubber fatigue failure mechanism and common analysis methods are described.(2) The life estimation method on rubber component under multiaxial fatigue load is introduced and the CED theory and model application characteristics are emphasized.(3) 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 potensital crack initiation area, and can characterize critical surface.(4) The engineering application of multi-axial fatigue life prediction method: First of all, the fatigue life and dangerous zone of the original structure of rubber bushing is analyzed. Higher reliability of prediction result is verified through bench test. Secondly, according to the prediction of fatigue analysis, the cause of fatigue risk area is analyzed and the original structure is optimized so as to develop a modified structure of rubber bushing which can meet the requirements of engineering application design.Finally, fatigue prediction and bench test of the modified structure are carried out. The results of comparative analysis illustrate the feasibility of the Abaqus&Endurica platform in under multi-axial loading of the rubber bushing fatigue life prediction.(5) Main content and relevant conclusions are summarized in this passage and the future research work is put forward.