NONLINEAR ANALYSIS OF FLUID SUSPENSIONS FOR TRACKED AIR CUSHION VEHICLES.
Nonlinear modeling of vehicle air cushion suspensions in heave mode is discussed. Comparisons are made with the small perturbation linearized models to determine the range of input disturbances, and cushion configurations for which the linear model provides a valid approximation to the nonlinear cushion model. Suspension performance characteristics are presented for transient guideway and external force (e. g. , wind gust) inputs to both linear and nonlinear cushion models. Large guideway inputs of the order of 100 percent of the equilibrium gap height and step external force input up to 25 percent of the equilibrium value are applied to several configurations with equilibrium operating gaps of 0. 125-0. 5 in. and suspension natural frequencies of 0. 5 to 2 hz. Influence of parametric variations on dynamic performance of nonlinear suspensions is discussed.