SOME OBSERVATIONS ON THE DYNAMIC ELASTIC-PLASTIC BUCKLING OF A STRUCTURAL MODEL

The use of a simple imperfection-sensitive elastic-plastic model for s tudying the non-linear buckling of short columns and cylndrical shells under dynamic axial compression is discussed in this paper. The axial impact loading of the model by a mass with an initial velocity is con sidered as a particular example. The critical impact velocities are de termined for wholly elastic and elastic-plastic materials with linear strain hardening characteristics. The results show that the maximum in itial kinetic energy at the transition between stable and unstable beh aviour after impact is sensitive to the magnitude of the material stra in hardening parameter. It is also evident from the results that impac t due to larger masses leads to larger lateral displacements at buckli ng and that the instability of a column is more sensitive to the prese nce of initial imperfections at higher impact velocities. Some guidanc e is offered on the choice of the various parameters in the idealized model for the analysis of practical engineering structures.