Inelastic Buckling of Structures

Abstract

In the elastic stability analysis discussed in the preceding chapters, the material of the structure is presumed to behave according to Hooke’s Law i.e. the stress in the structure does not exceed the initial yield stress in compression and the member undergoes configuration or shape failure. For many real structures the elastic analysis results in flexural buckling load estimation that exceeds the one associated with the yield stress or proportional limit stressof the material. This is especially true for the relatively short or stocky compression members in the framed structures. For this category of members the prorated design stresses based on safety factors, generally, fall in the range of plastic or inelastic behaviour. For steel framed structures many real designs occur in that range and most of the concrete framed structure columns are short. In these shorter columns the elastic limit is exceeded before the inception of buckling, and the modulus of elasticity E, hitherto constant, becomes a function of critical stress σ _cr= P _cr/A.