Structural Stability

Structures fail due to material failure or because of buckling or structural instability. More and more failures are occurring due to structural instability because high strength materials in combination with large size structures are used presently. General concepts of buckling and why it occurs are explained. Both equilibrium and energy methods are used to solve stability problems. Different types of buckling, e.g., bifurcation, limit load also called snap through buckling, and finite disturbance buckling are defined. Rigid bar columns are used to study the buckling behavior. Rigid bar assemblies that are cantilever and simply supported columns are studied for different loading conditions. Both linear and rotational springs are used to support the rigid bar columns including a truss. It is shown the equilibrium method gives the critical load, energy method gives the critical load and the type of equilibrium, stable or unstable. Large displacement analysis is performed to know the post‐buckling behavior of rigid bar columns. Load versus deformation graphs are plotted to know whether the structure will be in stable or unstable equilibrium at the critical load. Taylor series is used to solve stability problems. The effect of imperfections is studied. There are six practice problems and five references at the end of the chapter.