Stability of rods at yield plateau

Abstract

Annotation. The aim of the article  is to examine the features of buckling under axial compression elastic-plastic rods, which has a yield plateau  material yield compression in the diagram. Numerical experiments show that the model perfectly plastic behavior should be reconsidered. Found that shelf fluidity is not formed by a homogeneous flow of the entire sample, through the distribution of plastic zone along rod. Thus, only a portion of the rod is in a plastic state, and the rest remains resilient. In this regard, there are issues related to the interaction of unstable material with geometric (or structural) buckling of the rod. In carrying out engineering calculations in building mechanics is assumed that the core of mild steel, chart uniaxial tension which has a yield plateau, lose stability immediately upon reaching the yield point. Clarification of the critical load for these cores can increase resource efficiency rods, by improving its stability and will reduce the consumption of materials design. Methods: solving the problem on eigenvalues for ordinary differential equation with piecewise constant coefficients; construction of critical load, depending on the length of the rod. Results. The problem of buckling of the core material with a yield plateau and built a critical dependence on Shengli strain on the length of the rod. The practical significance of the work lies in the fact that it received results can be used in the practice of engineering calculations of building structures on the stability and strength to improve resource efficiency and economy of metal structures.