Dynamic Analysis in Full Degrees of Freedom of Rotor’s Radial Rub-impact with the Consideration of Nonlinear Fluid-structure Interaction Forces

2008 ◽  
Vol 44 (06) ◽  
pp. 199
Author(s):  
Zhenwei YUAN
Keyword(s):  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
Fluid Structure Interaction ◽  
Interaction Forces ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Nonlinear Fluid

Implementation of a Stuctural-Acoustic Homogenized Method for the Dynamic Analysis of a Tube Bundle With Fluid Structure Interaction Modeling in ABAQUS: Formulation and Applications

2014 ◽  
Author(s):  
Eric Veron ◽  
Jean-François Sigrist ◽  
Daniel Broc
Keyword(s):  
Dynamic Analysis ◽  
Degrees Of Freedom ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Acoustic Method ◽  
Computational Time ◽  
Physical Point ◽  
Fluid Structure ◽  
Structure Interaction

The present paper deals with the dynamic analysis of a tube bundle with Fluid Structure Interaction (FSI) modeling using a structural acoustic homogenized method. Such a coupled problem leads to many degrees of freedom [a system of very large matrices] to compute tube displacements and pressure in the acoustic domain, it is therefore irrelevant to use standard coupled methods in industrial cases. Instead, specific modelings have to be used, such as structural acoustic homogenized method. Implementation and applications of such a technique within the general finite element code ABAQUS are performed using the so-called UEL Fortran subroutine. Firstly, general theoretical aspects on the homogenized method proposed by Broc & Sigrist are revisited. Then, subroutines developments are validated comparing results from the homogenized method to those of a standard approach on the representative case of a 10×10 tube bundle in two-dimensional and three-dimensional configurations subjected to seismic loadings. Results show that: (i) homogenized elements can easily be used as standard elements from the ABAQUS elements library, (ii) the homogenized approach is accurate on a physical point of view and (iii) considerably reduces modeling effort and computational time compared to a standard structural acoustic method.

Modal Analysis of Fluid-Structure Interaction in a Bent Pipeline

2016 ◽  
Author(s):  
Gudrun Mikota ◽  
Rainer Haas ◽  
Evgeny Lukachev
Keyword(s):  
Modal Analysis ◽  
Degrees Of Freedom ◽  
Coupling Effect ◽  
Fluid Structure Interaction ◽  
Interaction Model ◽  
Coupling Mechanism ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Resonance Coupling ◽  
Measured Frequency Response

Fluid-structure interaction in a bent pipeline is investigated by modal methods. Measured frequency response functions between flow rate excitation and pressure response indicate a coupling effect near the third pipeline resonance. Using modal coordinates for the hydraulic and the mechanical subsystems, a two-degrees-of-freedom study of resonance coupling is carried out. An experimental modal analysis of the coupled hydraulic-mechanical system confirms the predicted resonance splitting; it illustrates the coupling mechanism and shows the relevant mechanical part. An analytical fluid-structure interaction model succeeds in reproducing the measured coupling effect. This model is also used for modification prediction; it demonstrates that an appropriate assembly of mass and damping on the pipeline can help to reduce hydraulic resonance amplitudes.

Simulation of Fluid Flow Using Reduced-Order Modeling by POD Approach Applied to a Fixed Tube Bundle System

2010 ◽  
Author(s):  
Marie Pomarede ◽  
Erwan Liberge ◽  
Aziz Hamdouni ◽  
Elisabeth Longatte ◽  
Jean-Franc¸ois Sigrist
Keyword(s):  
Dynamic Analysis ◽  
Steam Generator ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Reduced Model ◽  
Steam Generator Tube ◽  
Fluid Structure ◽  
Reduced Order ◽  
Structure Interaction ◽  
Tube Bundles

Tube bundles in steam boilers of nuclear power plants and nuclear on-board stokehold are known to be exposed to high levels of vibrations. This coupled fluid-structure problem is very complex to numerically set up, because of its three-dimensional characteristics and because of the large number of degrees of freedom involved. A complete numerical resolution of such a problem is currently not viable, all the more so as a precise understanding of this system behaviour needs a large amount of data, obtained by very expensive calculations. We propose here to apply the now classical reduced order method called Proper Orthogonal Decomposition to a case of 2D flow around a tube bundle. Such a case is simpler than a complete steam generator tube bundle; however, it allows observing the POD projection behaviour in order to project its application on a more realistic case. The choice of POD leads to reduced calculation times and could eventually allow parametrical investigations thanks to a low data quantity. But, it implies several challenges inherent to the fluid-structure characteristic of the problem. Previous works on the dynamic analysis of steam generator tube bundles already provided interesting results in the case of quiescent fluid [J.F. Sigrist, D. Broc; Dynamic Analysis of a Steam Generator Tube Bundle with Fluid-Structure Interaction; Pressure Vessel and Piping, July 27–31, 2008, Chicago]. Within the framework of the present study, the implementation of POD in academic cases (one-dimensional equations, 2D-single tube configuration) is presented. Then, firsts POD modes for a 2D tube bundle configuration is considered; the corresponding reduced model obtained thanks to a Galerkin projection on POD modes is finally presented. The fixed case is first studied; future work will concern the fluid-structure interaction problem. Present study recalls the efficiency of the reduced model to reproduce similar problems from a unique data set for various configurations as well as the efficiency of the reduction for simple cases. Results on the velocity flow-field obtained thanks to the reduced-order model computation are encouraging for future works of fluid-structure interaction and 3D cases.

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