Speaker
Description
It is well-established that slender columns subjected to compression may fail by buckling and that the introduction of imperfections can significantly reduce the load-bearing capacity. It is therefore necessary to ensure an accurate representation of imperfections to correctly determine the failure loads of slender structures. Imperfections in slender columns are typically modeled using either geometric imperfections or load eccentricity. However, the existing imperfection types are unable to represent imperfections like, e.g., a footpoint rotation of a bearing or foundation, erroneous angular alignment of fixtures, or deformation of structural elements to which a slender column is rigidly connected. Here, rotations of a clamped boundary result in an additional type of imperfection.
In this work, we are introducing rotation imperfections to the classical Euler buckling problem transforming the eigenvalue problem into a deformation problem. We are presenting an analytical closed-form solution for the load-deformation behavior of a column with rotation imperfections. The model is compared to a numerical study showing very good agreement. Analyzing a simple study of columns connected to a surrounding structure we show that the introduction of rotation imperfection can lead to the clamped columns exhibiting lower critical loads than pined joint columns with free end-point rotations. Additionally, the model is expanded to allow for kinematical controlled boundary rotations using a semi-analytical approach.
