THE PRIMARY BENDING EFFECT AND THE BUCKLING BOUNDARY-VALUE PROBLEM INELASTIC FRAMED STRUCTURE

This study deals with the stability analysis of elastic framed structu res, free from imperfections, which are acted upon by concentrated joi nt loads. Attention is focused on the conditions under which primary b ending is ruled out then the above analysis leads to a classical eigen value problem from which one can establish critical buckling loads and corresponding buckling modes. To this end by using simple frames as m odels the individual and coupling effect of various parameters (e.g. g eometric imperfections, elastic supports, etc.) for which these struct ures may exhibit a trivial fundamental equilibrium path (from the onse t of loading up to its critical value) are thoroughly discussed. It is also found that in case of non-existence of primary bending the compo nents of the joint loads in the directions of the bars of the joints, coincide with the corresponding axial (internal) forces. (C) 1997 Else vier Science Ltd.