Characteristics Of Metal Rubber Damper Dynamics

Metal-rubber(MR)is a kind of porous elastic material,made of stainless steel wire by molding art. It is used in high temperature,high pressure,vacuum,and other condition. Contact points of metal wires produce dry friction damping to vibration attenuation. MR possesses good nonlinear damping characteristics and obvious hysteresis phenomenon. the distribution of the metal wire is mixed and disorderly,so the establishing of mathematical model and physical model is difficult.The frequency equation under harmonic excitation was derived by the technique of Fourier series expansion and harmonic balance method (FHB). The frequency equation was resolved and the figure of amplitude-frequency characteristics was obtained by using matlab. It was compared that the effect of the linear term, the cubic power nonlinear term, the fifth power nonlinear term and seventh power nonlinear term on amplitude-frequency characteristics of metal rubber shock absorber . It was found that the linear term and the cubic power nonlinear term plays the important role in the system response, so that it is not necessary to consider the fifth power nonlinear term unless its magnitude is greater than 108, and the seventh power nonlinear term unless its magnitude is greater than 1011.Based on the metal rubber friction energy dissipation mechanism,a cantilever truss contact model is established. The load and displacement analytic expression is obtained by the model. Based on cantilever truss model,the finite element analysis software ANSYS is used to simulate the deformation process of circular MR with the different relative density. The theoretical and numerical simulation hysteresis loops are proximate, it shows that the theoretical calculation model is feasible. The analysis shows that the circular MR with smaller relative density possesses bigger consumption characteristics, smaller stiffness and wider soft characteristics stage.