STOCHASTIC RESPONSE OF BASE-EXCITED COULOMB OSCILLATOR

The probabilistic solution to the stochastic responses of a rigid structure connected to a foundation with Coulomb friction-type base isolation subjected to stationary Gaussian white-noise-type ground excitations is investigated. The base isolation system which can be described with a base-excited Coulomb oscillator utilizes sliding bearing in which the coefficient of friction exhibits strong dependence on the sliding velocity. The analytical probabilistic solutions are obtained with both an equivalent linearization procedure and a new method proposed recently. The analytical solutions are verified by Monte Carlo simulation and the results show that the method utilized yields better solutions than the equivalent linearization procedure. It is also found that friction-type base isolation systems exhibit softening non-linearity and the method utilized is well suited to systems with softening non-linearity.