ABSTRACT
This chapter shows that the energy functionals of many structural models, present relevant smoothness properties in their energy spaces and in the neighborhood of their fundamental equilibrium states. It has thus been possible to analyze, according to methods and procedures, the stability at buckling of many structural elements. The same approach, but limited to buckling analysis, will be now applied to the “structural continuum”, able to represent a generic tridimensional structural element. Special constraint conditions among displacements and their derivatives fit the tridimensional elastic body to the chosen structural model. The critical state of equilibrium of a structural system can be analyzed by means of the classical “adjacent equilibrium method”. Because of the high stiffness of the structural material, changes of the areas due to the deformation of the medium produce, in fact, only negligible changes on the incremental stress components.
