Dynamic Stability of Structures: Imperfection Sensitive Systems, Acted Upon by Step-Loads

摘要

Structural configurations subjected to loads that fall under the category of an ideal impulse are considered. Emphasis is placed on systems that exhibit either limit point instability or an unstable bifurcational branch in the post-buckling region. The purpose of the present work is to investigate the concept of dynamic stability of structural elements subjected to step-loads and develop the related criteria and estimates for finding critical conditions. The step load consists of a suddenly applied load of constant magnitude and finite duration t sub o, and the investigation will include the two extreme cases of t sub o approaches infinity and t sub o approaches 0 (ideal impulse). Moreover, the effect of various parameters (small damping and preloading) on the critical conditions is studied. The developed solution methodology is demonstrated through a geometrically imperfect model and a load eccentricity model of one degree of freedom and a snap-through model of two degrees of freedom. (Author)