Vibration of Circular Plates in Contact With Water

1991 ◽  
Vol 58 (2) ◽  
pp. 480-483 ◽  
Author(s):  
M. K. Kwak
Keyword(s):  
Natural Frequencies ◽  
Integral Transformation ◽  
Integral Equation Method ◽  
Mass Effect ◽  
Dual Integral Equation ◽  
Practical Reasons ◽  
Virtual Mass ◽  
Circular Plates ◽  
Transformation Technique ◽  
Simply Supported

This paper is concerned with the virtual mass effect on vibrating circular plates due to the presence of water. Natural frequencies in water can be estimated from natural frequencies in air by using the approximate formula, which mainly depends upon the so-called added virtual mass incremental factor. The added virtual mass incremental factor is a function of geometry, material properties of the plates and mostly boundary conditions of the plates, and water domain. For practical reasons, the added virtual mass incremental factor is likely to be nondimensionalized. In this paper, the nondimensionalized added virtual mass incremental factors for circular plates having simply-supported, clamped, and free edges are obtained by employing the integral transformation technique in conjunction with the dual integral equation method. It is found that the effect of water on the natural frequencies decreases with order.

Hydroelastic Vibration of Free-Edge Annular Plates

1999 ◽  
Vol 121 (1) ◽  
pp. 26-32 ◽  
Author(s):  
M. K. Kwak ◽  
M. Amabili
Keyword(s):  
Free Surface ◽  
Boundary Conditions ◽  
Natural Frequencies ◽  
Mass Effect ◽  
Free Edge ◽  
Virtual Mass ◽  
Hankel Transformation ◽  
Transformation Technique ◽  
Different Boundary Conditions ◽  
Annular Plates

This paper is concerned with the virtual mass effect due to the presence of water on the natural frequencies of free-edge annular plates resting on free surface or completely submerged, which has never been studied theoretically. Experiments were carried out for free-edge annular plates to find the so-called nondimensionalized added virtual mass incremental factors. In this paper, theoretical nondimensional added virtual mass incremental factors are obtained by employing the Hankel transformation technique in conjunction with the Fourier-Bessel series approach. It is found that the theoretical nondimensionalized added virtual mass incremental factors for free-edge annular plates resting on free-surface agree well with experimental ones. The proposed method can be applied to different boundary conditions of plates.

scholarly journals INFLUENCE OF A LIQUID ON THE NATURAL FREQUENCIES OF ALMOST CIRCULAR PLATES

2014 ◽  
Vol 06 (05) ◽  
pp. 1450052 ◽  
Author(s):  
MANUEL GASCÓN-PÉREZ ◽  
PABLO GARCÍA-FOGEDA
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Vibration Mode ◽  
Normal Modes ◽  
Virtual Mass ◽  
Circular Plates ◽  
Hankel Transformation ◽  
Fluid System ◽  
Surrounding Fluid ◽  
Good Agreement

In this work, the influence of the surrounding fluid on the dynamic characteristics of almost circular plates is investigated. First the natural frequencies and normal modes for the plates in vacuum are calculated by a perturbation procedure. The method is applied for the case of elliptical plates with a low value of eccentricity. The results are compared with other available methods for this type of plates with good agreement. Next, the effect of the fluid is considered. The normal modes of the plate in vacuum are used as a base to express the vibration mode of the coupled plate-fluid system. By applying the Hankel transformation the nondimensional added virtual mass 2 increment (NAVMI) are calculated for elliptical plates. Results of the NAVMI factors and the effect of the fluid on the natural frequencies are given and it is shown that when the eccentricity of the plate is reduced to zero (circular plate) the known results of the natural frequencies for circular plates surrounded by liquid are recovered.

Comments on “natural frequencies of simply supported circular plates”

1981 ◽  
Vol 76 (1) ◽  
pp. 143-145
Author(s):  
P.A.A. Laura ◽  
G.M. Ficcadenti ◽  
R.O. Grossi
Keyword(s):  
Natural Frequencies ◽  
Circular Plates ◽  
Simply Supported

Natural Frequencies of Mindlin Circular Plates

1980 ◽  
Vol 47 (3) ◽  
pp. 652-655 ◽  
Author(s):  
T. Irie ◽  
G. Yamada ◽  
S. Aomura
Keyword(s):  
Natural Frequencies ◽  
Plate Theory ◽  
Mindlin Plate ◽  
Circular Plates ◽  
Simply Supported ◽  
Mindlin Plate Theory ◽  
Clamped Edges

The natural frequencies of vibration based upon the Mindlin plate theory are tabulated for uniform circular plates with free, simply supported, and clamped edges for the first several tens modes.

Natural Frequency of Laminated Composite Plates Using a Sinusoidal Theory

2014 ◽  
Vol 709 ◽  
pp. 148-152
Author(s):  
Guo Qing Zhou ◽  
Ji Wang ◽  
Song Xiang
Keyword(s):  
Differential Equations ◽  
Analytical Method ◽  
Deformation Theory ◽  
Natural Frequencies ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Simply Supported ◽  
Sinusoidal Shear Deformation Theory

Sinusoidal shear deformation theory is presented to analyze the natural frequencies of simply supported laminated composite plates. The governing differential equations based on sinusoidal theory are solved by a Navier-type analytical method. The present results are compared with the available published results which verify the accuracy of sinusoidal theory.

Fluid Added Mass Effect in the Modal Response of a Pump-Turbine Impeller

2009 ◽  
Author(s):  
Eduard Egusquiza ◽  
Carme Valero ◽  
Quanwei Liang ◽  
Miguel Coussirat ◽  
Ulrich Seidel
Keyword(s):  
Natural Frequencies ◽  
Experimental Tests ◽  
Mass Effect ◽  
Added Mass ◽  
Mode Shapes ◽  
Pump Turbine ◽  
Modal Response ◽  
Surrounding Fluid ◽  
Turbine Impeller ◽  
Good Agreement

In this paper, the reduction in the natural frequencies of a pump-turbine impeller prototype when submerged in water has been investigated. The impeller, with a diameter of 2.870m belongs to a pump-turbine unit with a power of around 100MW. To analyze the influence of the added mass, both experimental tests and numerical simulations have been carried out. The experiment has been performed in air and in water. From the frequency response functions the modal characteristics such as natural frequencies and mode shapes have been obtained. A numerical simulation using FEM (Finite Elements Model) was done using the same boundary conditions as in the experiment (impeller in air and surrounded by a mass of water). The modal behaviour has also been calculated. The numerical results were compared with the available experimental results. The comparison shows a good agreement in the natural frequency values both in air and in water. The reduction in frequency due to the added mass effect of surrounding fluid has been calculated. The physics of this phenomenon due to the fluid structure interaction has been investigated from the analysis of the mode-shapes.

A semi-analytical three-dimensional free vibration analysis of functionally graded curved panels integrated with piezoelectric layers

2014 ◽  
Vol 21 (4) ◽  
pp. 571-587 ◽  
Author(s):  
Hamid Reza Saeidi Marzangoo ◽  
Mostafa Jalal
Keyword(s):  
Boundary Conditions ◽  
Vibration Analysis ◽  
Natural Frequencies ◽  
Differential Quadrature Method ◽  
Three Dimensional ◽  
Free Vibration Analysis ◽  
Functionally Graded ◽  
Simply Supported ◽  
Piezoelectric Layers ◽  
Curved Panels

AbstractFree vibration analysis of functionally graded (FG) curved panels integrated with piezoelectric layers under various boundary conditions is studied. A panel with two opposite edges is simply supported, and arbitrary boundary conditions at the other edges are considered. Two different models of material property variations based on the power law distribution in terms of the volume fractions of the constituents and the exponential law distribution of the material properties through the thickness are considered. Based on the three-dimensional theory of elasticity, an approach combining the state space method and the differential quadrature method (DQM) is used. For the simply supported boundary conditions, closed-form solution is given by making use of the Fourier series expansion, and applying the differential quadrature method to the state space formulations along the axial direction, new state equations about state variables at discrete points are obtained for the other cases such as clamped or free-end conditions. Natural frequencies of the hybrid curved panels are presented by solving the eigenfrequency equation, which can be obtained by using edges boundary conditions in this state equation. The results obtained for only FGM shell is verified by comparing the natural frequencies with the results obtained in the literature.

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