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Deformation modes in the finite element absolute nodal coordinate formulation

✍ Scribed by Hiroyuki Sugiyama; Johannes Gerstmayr; Ahmed A. Shabana


Publisher
Elsevier Science
Year
2006
Tongue
English
Weight
383 KB
Volume
298
Category
Article
ISSN
0022-460X

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✦ Synopsis


The objective of this study is to provide interpretation of the deformation modes in the finite element absolute nodal coordinate formulation using several strain definitions. In this finite element formulation, the nodal coordinates consist of absolute position coordinates and gradients that can be used to define a unique rotation and deformation fields within the element as well as at the nodal points. The results obtained in this study clearly show cross-section deformation modes eliminated when the number of the finite element nodal coordinates is systematically and consistently reduced. Using the procedure discussed in this paper one can obtain a reduced order dynamic model, eliminate position vector gradients that introduce high frequencies to the solution of some problems, achieve the continuity of the remaining gradients at the nodal points, and obtain a formulation that automatically satisfies the principle of work and energy. Furthermore, the resulting dynamic model, unlike large rotation finite element formulations, leads to a unique rotation field, and as a consequence, the obtained formulation does not suffer from the problem of coordinate redundancy that characterizes existing large deformation finite element formulations. In order to accurately define strain components that can have easy physical interpretation, a material coordinate system is introduced to define the material element rotation and deformation. Using the material coordinate system, the Timoshenko–Reissner and Euler–Bernoulli beam models can be systematically obtained as special cases of the absolute nodal coordinate formulation beam models. While a constraint approach is used in this study to eliminate the cross-section deformation modes, it is important to point out as mentioned in this paper that lower-order finite elements, some of which already presented in previous investigations, can be efficiently used in thin and stiff structure applications.


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A two-dimensional shear deformable beam
✍ K.E. Dufva; J.T. Sopanen; A.M. Mikkola πŸ“‚ Article πŸ“… 2005 πŸ› Elsevier Science 🌐 English βš– 424 KB

In this study, a new two-dimensional shear deformable beam element is proposed for large deformation problems. The kinematics of the beam are defined using an exact displacement field, where the rotation angles of the cross-section caused by bending and shear deformations are described separately. C