Research Spotlight: Non-Uniform Modal Decomposition of Thin-Walled Members by the Constrained Finite Element Method

2017 Annual Stability Conference Presentation

Session S12 – Advances in Stability Analysis
Friday, March 24, 2017
1:00 pm

Non-Uniform Modal Decomposition of Thin-Walled Members by the Constrained Finite Element Method

In the paper a new method, the constrained finite element method is applied for the modal decomposition of thin-walled members. With the help of this method the thin-walled member can be enforced to deform in accordance with some predefined criteria. In stability analysis, thus, it becomes straightforward to directly study various buckling types, for example flexural buckling, flexural-torsional buckling, distortional buckling, etc., as desired by the user. The main focus of the paper is on the special feature of the method that modal decomposition can be performed for non-uniform members, too, more specifically, for any members built of from prismatic segments. The connecting segments can have different cross-sections: this makes it possible, among others, to build a single realistic shell model with e.g., directly modeling gusset plates or strengthening plates, while still to utilize modal decomposition advantages. Moreover, the segments can be constrained into different deformation modes, that is the enforced deformations may vary from segment to segment: this allows calculating the critical load value directly to a certain type of buckling in a certain part of the member. Thus, unlike in a regular shell finite element buckling analysis, it is not necessary to check hundreds of mostly interacted buckling modes to find a desired mode, but this desired mode can be found in a way which is more direct, more objective, and more efficient.

Sándor Ádány, Budapest University of Technology and Economics, Budapest, Hungary