ABSTRACT
This chapter discusses the conditions for the equilibrium of a structure and then aims to relate the conditions at bifurcation buckling. It considers equilibrium for a structure of a linear elastic material. The chapter also discusses the deflection of the structure under increasing load in relation to the changes which occur in the energy of the system used to apply the loads, in the strain energy stored in the structure, and in the potential energy of the loads. It provides the principle of virtual work for a structure in equilibrium. This is then related to the first variation of the total potential and used to derive the principle of stationary total potential. The chapter explains the conditions of stable, neutral, and unstable equilibrium. It discusses the relationship between the condition of neutral equilibrium and the principle of conservation of energy during buckling.
