A numerical approach to directly compute nonlinear normal modes of geometrically nonlinear finite element models

2014 ◽  
Vol 46 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Robert J. Kuether ◽  
Matthew S. Allen
Keyword(s):  
Finite Element ◽  
Normal Modes ◽  
Nonlinear Normal Modes ◽  
Numerical Approach ◽  
Nonlinear Finite Element ◽  
Finite Element Models ◽  
Geometrically Nonlinear ◽  
Nonlinear Normal

Characterization of Nonlinear Coupled Dynamics in Sandwich Structures

2008 ◽  
Author(s):  
Ioannis T. Georgiou
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Geometric Nonlinearity ◽  
Sandwich Structures ◽  
Normal Modes ◽  
Element Model ◽  
Nonlinear Normal Modes ◽  
High Fidelity ◽  
Coupled Dynamics ◽  
Nonlinear Normal

In this work, the nonlinear coupled dynamics of a sandwich structure with hexagonal honeycomb core are characterized in terms of Proper Orthogonal Decomposition modes. A high fidelity nonlinear finite element model is derived to describe geometric nonlinearity and displacement and rotation fields that govern the coupled dynamics. Contrary to equivalent continuum models used to predict vibration properties of lattice and sandwich structures, a high fidelity finite element model allows for a quite detailed description of the distributed complicated geometric nonlinearity of the core. It was found that the free dynamics excited by a blast load and the forced dynamics excited by a harmonic force posses POD modes which are localized in space and time. The processing of the simulated dynamics by the Time Discrete Proper Transform forms a means to study the nonlinear coupled dynamics of sandwich structures in the context of nonlinear normal modes of vibration and reduced order models.

Modal Substructuring of Geometrically Nonlinear Finite-Element Models

AIAA Journal ◽  
2016 ◽  
Vol 54 (2) ◽  
pp. 691-702 ◽  
Author(s):  
Robert J. Kuether ◽  
Matthew S. Allen ◽  
Joseph J. Hollkamp
Keyword(s):  
Finite Element ◽  
Nonlinear Finite Element ◽  
Finite Element Models ◽  
Geometrically Nonlinear

scholarly journals Evaluation of Geometrically Nonlinear Reduced-Order Models with Nonlinear Normal Modes

AIAA Journal ◽  
2015 ◽  
Vol 53 (11) ◽  
pp. 3273-3285 ◽  
Author(s):  
Robert J. Kuether ◽  
Brandon J. Deaner ◽  
Joseph J. Hollkamp ◽  
Matthew S. Allen
Keyword(s):  
Normal Modes ◽  
Nonlinear Normal Modes ◽  
Geometrically Nonlinear ◽  
Reduced Order Models ◽  
Reduced Order ◽  
Nonlinear Normal
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