RESPONSE OF A COULOMB SYSTEM TO STOCHASTIC EXCITATION

The stochastic response of a rigid mass, the motion of which is restrained by Coulomb friction, is examined. An approximate technique using a pulse train excitation is developed to estimate the mean and variance of the response. The method is shown to be capable of predicting the trends in the displacement variance when the input has little energy at low frequencies, in contrast to the equivalent linearization technique which predicts erroneous trends for this type of excitation. A refinement of the method, which accounts for overlaps in the excitation pulses, is shown to improve the accuracy of the technique when compared with simulation results. As an example of its application, the method is used to predict the response of a simple stick-slip system subjected to earthquake-like excitation. © 1992.