Finite Element Analysis And Life Prediction Of Elastic Bearing Under Complex Loads

As the important part of the helicopter connecting shaft and blade, the fatigue damage directly affects the safety of the aircraft. According to the working conditions and structural characteristics of the elastic bearing, the fatigue problem is essentially a multi axial fatigue problem for rubber materials. Considering the complexity of the multi axial fatigue problem of rubber materials, there is no satisfactory forecasting model. Based on the fatigue problem of rubber and fatigue of metal materials, the fatigue life of elastic bearing under the load spectrum is studied,the main work is as follows:This paper introduces several commonly used equivalent mechanical parameters can be seen in the equivalent parameter method of uniaxial loading fatigue life prediction has been made good results, but for multi axis there is no mechanical parameters achieved very good results. In addition, this paper introduces the cracking energy method of Mars, and deduces the cracking energy of 3D case.In this paper,the maximum principal elongation, Von Mises strain,strain energy density,by using equivalent parametric method,listed to density under various conditions of fatigue prediction effect comparison,it was found that the von Mises strain is a relatively good equivalent parameters. Based on the stress field method of metal fatigue analysis, the strain field strength method for fatigue analysis of elastic bearing is presented. And an equivalent shear strain fatigue parameter is proposed.Using the APDL parameter language of ANSYS and the geometrical parameters of the elastic bearing, the fast modeling of the parametric program is written. The simple stress analysis(including compression, bending and torsion) of the elastic bearing is carried out, and the results of the calculation of the stiffness deformation relationship are very good. The fatigue load spectrum(31 kinds of complex operating conditions) of the elastic bearing are simulated and analyzed. According to the comparison of the calculation results. It is found that the equivalent shear strain peak position, and the elastic bearing the true failure region was the same, so it can be considered equivalent shear strain is a reasonable fatigue analysis parameters. Using large deformation theory, combined with the pure torsion load finite element calculation results, it derives the functional relationship derived equivalent shear strain and the Nominal shear strain of experimental observations, and then obtain the parameters of fatigue life formula to true von Mises strain. At the end of this paper, based on the Miner linear model proposed elastic shaft bearing load spectrum fatigue life prediction model, combined with the fatigue curve and the simulation of working conditions of rubber bearing, the fatigue life of the elastic bearing is predicted, and the results are satisfactory.