چكيده به لاتين
Today, stability and vibration reduction is essential specifically in railway industry due to widespread use of transportation vehicles. Elastomeric materials are widely used for different applications such as shock absorbers, primary or second suspension, isolators etc. Despite prevalent applications of these materials, it is still challenging to understand and predict the actual behavior of rubber. Due to nonlinearity and unique properties of rubber, different constitutive models have been developed. In this study, a hyper-viscoelastic model based on generalized Maxwell is used. The model is compared with reference experimental rubber tests and Abaqus default model. Mechanical characteristic of the rubber bushing due to harmonic excitations is analyzed to clarify the stiffness and damping dependencies on the excitation frequency and the displacement amplitude using a UMAT subroutine in Abaqus. In order to investigate the efficiency of the Umat, another geometry is modeled. Comparisons between the subroutine model developed for this investigation and the existing experimental rubber bushing tests showed that the results are in good agreement with 10% error. However, the error value is more than 40% for the default model compared to experimental tests. Rate dependent and amplitude dependency behavior of rubber were studied and results showed that dynamic stiffness and phase angle decrease with increasing amplitude, whereas they increase with increasing frequency. Maximum phase angle were observed in low amplitudes and mid-frequencies. Furthermore, high filled natural rubber has higher dynamic stiffness and phase angle than low filled natural rubber.
Keywords: Rubber bushing, Frequency dependence, Dynamic stiffness, Nonlinear model, Finite element analysis, filled rubber
