Stochastic Analysis of Elasto-Plastic Systems

A new approximate and simple technique is presented for predicting the response of elasto-plastic type yielding systems under stationary random excitation. The total response is spilt into a low frequent drift response and a remaining process, the behavior of which is determined by effective damping and stiffness parameters. These parameters are defined on the basis of open loop properties. A new estimate of the yield increment is proposed. It is computed iteratively. The procedure is applicable for white noise as well as filtered noise input spectra. Correction factors are introduced to account for the variability of the input energy with frequency. The results for the yield increment, the effective parameters, the steady-state and transient response statistics, and the ductility ratios show a generally good agreement with simulation estimates.