ABSTRACT
Kounadis & Raftoyiannis (1990) investigated the nonlinear dynamic stability criteria of one degree of freedom under step loading, and concluded that the structure would buckle when the phasepoint velocity vanished regardless of the length of loading duration and damping effect. Kounadis (1991) subsequently studied two nonlinear twodegree-of-freedom systems under step loading with and without damping effect. It was shown that when viscous damping was incorporated, the lower bound of critical load for dynamic buckling could be estimated. Mallon et al. (2006) presented numerical means for analyzing a series of thin shallow arches subjected to a pulse load, and also found that the increase of damping coefficient would lead to an increasing of dynamic buckling critical load. Moreover, Lee (1996) investigated a rod with an intermediate spring support with a follower force at one end, and suggested that the damping effect cannot always be neglected especially for some particular engineering systems.
