DYNAMIC PULSE BUCKLING OF A SIMPLE ELASTIC-PLASTIC MODEL INCLUDING AXIAL INERTIA

The phenomenon of dynamic elastic-plastic buckling is studied using a simple imperfection-sensitive idealized model with elastic linear work hardening springs to simulate the elastic-plastic material behaviour. The stability theorem for autonomous systems is used to obtain the transition between stable and unstable behaviour. A step loading and three types of finite duration pressure pulses are examined. In some cases, several elastic-plastic cycles of spring deformations occur before the model shakes down to a wholly elastic behaviour. The various results show that the effects of a pulse loading are significant even for pulses having a duration comparable with the natural period of vibration. Furthermore, the model becomes more sensitive to the influence of initial imperfections as the pulse duration decreases.