Abstract
This study treats the dynamic stability of mechanical systems subjected to multi-directional excitations, such as dynamic buckling behavior, etc . A steel cylindrical pier is treated and modeled analytically as a thin cylindrical structure with an attached mass on its tip. The analysis is carried out by numerical simulations, where the horizontal and the vertical seismic loads are applied simultaneously. The effects of the horizontal and vertical input frequencies on the dynamic stability are studied. It is known that the seismic responses of the thin cylindrical shell structure tend to increase due to the coupling effects between the horizontal and vertical excitations, and that flattening phenomena make the cylindrical shell structures more unstable.
