Nonlinear Frequency Spectrum Analysis of Vibration System with ER Damper

The Electro-rheological (ER) fluid is a new kind of smart material which has been applied to various engineering problems. Using the viscous and bilinear hysteretic damping model, this paper discusses the nonlinear frequency spectrum by iterative perturbation method for nonlinear vibration system with ER damper. Iterative perturbation is based on the matrix perturbation. The initial frequencies are found by subspace iteration. The subsequent frequency spectrum of nonlinear states, which is based upon the tangent stiffness of the structure, is calculated by the iterative perturbation method. A numerical example is given to illustrate the method presented by this paper.