A model to evaluate dynamic stability of imperfection sensitive shells

The paper deals with the perturbation energy concept and its application to stability of imperfection sensitive structures under time-dependent loads. The evaluation of the stability is based on energy norms, which may be used for investigation of safety against buckling. Starting from a stable state of equilibrium the presented procedure allows to decide whether the structure stays for a certain load history within critical bounds, which separate the motion round the prebuckling state from a motion in the postbuckling region. The stability is proved by comparing the critical energy calculated by a static analysis and the load induced energy. Applications to a truss and a spherical shell illustrate the variety of the phenomena in dynamic buckling behaviour of elastic structures in case of impulsive loading and the accuracy of the proposed method.