ABSTRACT
The hypothesis of small displacements so far advanced considers the cardinal equations of statics (7.46) and (7.47) in relation to the undeformed structural configuration. In other words, the elastic displacements have been hypothesized as being so small as to make it possible for the deformed configuration to be confused with the undeformed one when the static characteristics are to be evaluated. In this chapter this hypothesis will be removed, and it will be shown how the solution of an elastic problem can represent in actual fact a condition of stable, neutral or unstable equilibrium, according to the magnitude of the load applied. Moreover, there exist, around the condition of neutral equilibrium, an infinite number of other similar conditions, characterized by different static parameters (applied loads) and kinematic parameters (configuration of the system).
