Effects of a geometric parameter on the buckling values and the post-buckling behavior Deformed shapes of the initially imperfect beam during various stages of deformation Distributions of internal forces during various stages of loading Figure A. Equilibrium paths of a fixed beam having initially small circular imperfection and deformed shapes at various stages of deformationPurpose: In this study, snap-buckling and post-buckling behavior of fixed beams having initially small circular imperfection under lateral loading is examined. In addition to the effects of a geometric parameter (which is a function of the thickness, radius and central angle of the circular neutral line of the undeformed beam) on buckling values, its effects on support reactions and internal forces are also investigated.
Theory and Methods:The governing differential equations obtained within the framework of the Euler-Bernoulli beam theory are transformed into algebraic equations with the help of the finite difference method. The resulting nonlinear algebraic equations are solved by the displacement-controlled Newton-Raphson method. By drawing loaddeflection graphs, the effects of the concerning geometric parameter on the buckling values and the postbuckling behavior are analyzed.
Results:Unlike the previous studies on the subject; the variations of the support reactions, the diagrams of the deformed shapes of the fixed beams having initially small circular imperfection as well as the diagrams of the internal forces at various stages of the loading including the buckling and post-buckling states are investigated for various values of the geometric parameter.
Conclusion:For fixed beams having an initially small imperfection under a vertical loading, not only the bending behavior but also the stability behavior should be examined. A geometric parameter which can be defined according to the geometry of an initially imperfect beam can have significant effects on the equilibrium paths, buckling values, support reactions, deformed shapes, and internal forces.