Vibration of dynamic systems under cyclostationary excitations

A special type of nonstationary, random excitation, called cyclostationary, is studied. The main characteristic of this type of excitation is that its statistical properties (e.g., the rms) vary periodically in time in contra st to a traditional, random stationary model, which assumes constant statis tical properties. Many engineering structures, such as a submarine propelle r, a turbine blade, and an internal combustion engine, are subjected to thi s type of excitation. A method for modeling the excitation and for calculat ing the response of such systems is presented. It is shown that the road ex citation on a vehicle driven on a road made of concrete slabs, whose length is constant, is cyclostationary. A cyclostationary model can yield conside rably more accurate estimates of the rms of the response as compared to a t raditional stationary model in this problem.