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

The use of a simple imperfection-sensitive elastic-plastic model for studying 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 considered as a particular example. The critical impact velocities are determined for wholly elastic and elastic-plastic materials with linear strain hardening characteristics. The results show that the maximum initial kinetic energy at the transition between stable and unstable behaviour after impact is sensitive to the magnitude of the material strain hardening parameter. It is also evident from the results that impact due to larger masses leads to larger lateral displacements at buckling and that the instability of a column is more sensitive to the presence of initial imperfections at higher impact velocities. Some guidance is offered on the choice of the various parameters in the idealized model for the analysis of practical engineering structures.