Abstract: The nonlinear isolation system is popular in modern isolation mounting. By using Fokker-Planck equation and the statistical linearization met hod and under the condition of random excitation are discussed in this article the best damping selection of the dashpots of the stiffening nonlinear stiffness, the response characteristics of the single-degree-of-freedom isolation system ofnon-antisymmetrical and nonlinear stiffness, and the response analysis of two-degree-of-freedom nonlinear isolation systems. The selection of some parameters of the nonlinear isolation system is also dealt with by virtue of calculation examples.

Key words: homothetic motion, Steiner formula, Holditch theorem