Nonlinear Vibrations in a Parametrically Excited Fluid-Structure Interaction System With One-to-One Internal Resonance

2003 ◽  
Author(s):  
Takashi Ikeda
Keyword(s):  
Natural Frequency ◽  
Internal Resonance ◽  
Fluid Structure Interaction ◽  
Liquid Sloshing ◽  
Fluid Structure ◽  
Inertia Effects ◽  
Structure Interaction ◽  
Interaction System ◽  
Resonance Curves ◽  
One To One

Theoretical resonance curves prove that a structure’s resonance can facilitate liquid sloshing even when the internal resonance ratio is one-to-one. An investigation of nonlinear sloshing liquid vibrations in a rectangular tank supported by an elastic structure that is subjected to a vertical and sinusoidal excitation reveals that liquid sloshing occurs when the structure’s natural frequency is approximately equal to the natural frequency of sloshing, that is, in the state of one-to-one internal resonance, and that amplitude-modulated motions appear when the condition of the internal resonance deviates to some extent. A special consideration of the nonlinear inertia effects of liquid force and the use of Galerkin’s method help derive the differential (modal) equations governing the dynamic behaviors of the fluid-structure interaction system, while van der Pol’s method helps express the theoretical resonance curves. These theoretical results are in quantitative agreement with the experimental data.

Identification of Non-Linear Damping of Nuclear Reactor Components in Case of One-to-One Internal Resonance

2016 ◽  
Author(s):  
Joachim Delannoy ◽  
Marco Amabili ◽  
Brett Matthews ◽  
Brian Painter ◽  
Kostas Karazis
Keyword(s):  
Fuel Assembly ◽  
Internal Resonance ◽  
Fluid Structure Interaction ◽  
Fundamental Parameter ◽  
Pressurized Water ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Safety Margins ◽  
Non Linear ◽  
One To One

In Pressurized Water Reactors (PWR) assemblies are exposed to challenging thermal, mechanical, and irradiation loads during operation. Global core and local fuel assembly flow fields coupled with seismic excitation result in fuel assembly and fuel rod vibrations. The fact that vibrations may become excessive in certain conditions has consequences on operational safety margins in fuel assemblies designs. In order to understand how the fuel assembly responds dynamically to an external excitation, it is important to identify the main characteristics of the structures. Among them, the fuel assembly system damping is a fundamental parameter that is usually identified by a number of experiments involving fluid-structure interaction. Recent studies have shown that the damping ratio increases with the excitation force when the structure is entering large-amplitude vibrations, in which case the geometric non-linearities have to be taken into account. The present paper presents an advanced identification procedure developed to identify the system characteristics from experimental non-linear response curves obtained from forced vibration tests, accounting for fluid-structure interaction, at different excitation levels. Furthermore, the numerical tool developed in this analysis is capable of working with systems presenting one-to-one internal resonance, i.e. systems with symmetry such as circular tubes and circular cylindrical shells. The method relies on a harmonic decomposition of the displacement to cope with the data usually available by vibration measurements.

Analysis of a Nonlinear Friction Damping Mechanism in a Fluid-Structure Interaction System

1995 ◽  
Author(s):  
Oded Gottlieb ◽  
Michael Feldman ◽  
Solomon C. S. Yim
Keyword(s):  
Large Scale ◽  
Fluid Structure Interaction ◽  
Simulated Data ◽  
Identification Algorithm ◽  
Nonlinear Friction ◽  
Friction Damping ◽  
Restoring Force ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Interaction System

Abstract Analysis of a nonlinear friction damping mechanism in a fluid-structure interaction system is performed by combining a generalized averaging procedure with a recently developed identification algorithm based on the Hilbert transform. The system considered includes a nonlinear restoring force and a nonlinear dissipation force incorporating both viscous and structural damping. Frequency and damping response backbone curves obtained from simulated data are compared with analytical and approximate solutions and are found to be accurate. An example large scale experiment exhibiting viscous and Coulomb damping is also analyzed resulting in identification of system parameters.

Study of Critical Speed for a Flexible Drill String System Based on Fluid–Structure Interaction

2011 ◽  
Vol 105-107 ◽  
pp. 545-552
Author(s):  
Gui Jie Yu ◽  
Lei Fu ◽  
You Cai Yin
Keyword(s):  
Natural Frequency ◽  
Critical Speed ◽  
Fluid Structure Interaction ◽  
Drill String ◽  
Economic Returns ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Practical Engineering ◽  
Hoisting System ◽  
Multi Body

The TDS changed the drive mode and established a simple, flexible multi-body drill string system. The system consists of a derrick, a hoisting system, TDS, and a drill string system, and is inserted into a long, narrow borehole. The drill string then interacts with mud, the borehole wall, and the bottom hole, which generates resonance and increases the risk of drilling accidents. Natural frequency, which is related to the structure of the drill string, determines critical speed. In a vertical well, the transverse, torsional, and longitudinal fluid–structure interaction vibrations of the flexible multi-body drill string system within 1,700 m was analysed using the ANSYS. The natural frequency and the associated critical speed for different bottomhole assemblies (BHAs) were obtained. Results show that reasonably selecting the TDS rotation speed and optimizing BHA offer practical engineering applications for increasing drilling speed, reducing drilling accidents, and improving economic returns.

Coupling Model Analysis on Fluid Structure Interaction in Lifting Pipeling Based on ADINA

2012 ◽  
Vol 468-471 ◽  
pp. 238-244
Author(s):  
Zhao Wang ◽  
Zhi Jin Zhou ◽  
Hao Lu ◽  
Ze Jun Wen ◽  
Yi Min Xia
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Volume Concentration ◽  
Natural Frequencies ◽  
Fluid Structure Interaction ◽  
Element Model ◽  
Structure Design ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Finite Element Software

Using finite element software ADINA, three coupling models on fluid-structure interaction among internal fluid—pipe—external fluid in the lifting pipeline were researched. Firstly, coupling finite element model on fluid structure interaction of lifting pipeline was established and the first sixth order natural frequencies and principal vibration modes were attained at different ore conveying volume concentration and cross-section size of pipeline;Then natural frequencies of three couplings were compared with two couplings and no coupling according to the above condition, and FSI effect on natural frequency of pipeline was discussed. The calculation results were shown that the natural frequency of the pipe and its relative error reduced with the volume concentration and the relative wall thickness increased, which explain the reason that has better accuracy considering three couplings than other .These results have certain directive significance on the dynamic response, structure design and study of reduction vibration of lifting pipeline.

Nonlinear Behaviors of Three Dimensional Sloshing in the LNG Elastic Tank

2021 ◽  
Author(s):  
Zhongchang Wang ◽  
Meirong Jiang ◽  
Yang Yu
Keyword(s):  
Natural Frequency ◽  
High Frequency ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Surface Elevation ◽  
Fluid Structure ◽  
Elastic Case ◽  
Structure Interaction ◽  
Elastic Tank ◽  
Sloshing Pressure

Abstract Aiming at the nonlinear sloshing in the LNG tank, a three-dimensional elastic model is established to investigate the fluid structure interaction effect. For the transient flow and the tank motion, the direct coupling method is employed to calculate the interaction between the sloshing and the bulkhead. The finite element software ADINA is adopted to do the computation. The sloshing natural frequency is verified with the results of the theoretical formula. Different wall thicknesses, filling ratios and external excitations are considered and the structure natural frequency, surface elevation and sloshing pressure are obtained. The results of the elastic case are further compared with the rigid results and the nonlinear characteristics are extracted to see the hydro-elastic effect. The sloshing natural frequencies are agreed well with the theoretical results. Due to the influence of the fluid structure interaction, the couple frequencies are obviously less than those of the empty tank. With the increase of the wall thickness, the frequencies of the empty tank and the couple frequencies all increase gradually. For the surface elevation, the thinner the bulkhead thickness is, the more the high frequency component is. The free surface is relatively flat and stable in the rigid tank but tend to be chaotic for the elastic one. Due to the fluid structure interaction, the sloshing pressure of the elastic case presents obvious high-frequency fluctuation and the sloshing pressure in the elastic tank is smaller than that in the rigid tank. This model clearly shows the valuable ability to solve the three dimensional sloshing in the elastic tank.

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