Study of non-homogeneity effects on natural frequencies and mode shapes of polar orthotropic annular plate of exponentially varying thickness rest on elastic foundation

2021 ◽  
Author(s):  
Robin ◽  
Fateh Singh Gill ◽  
Neeraj Dhiman
Keyword(s):  
Elastic Foundation ◽  
Natural Frequencies ◽  
Annular Plate ◽  
Mode Shapes ◽  
Varying Thickness ◽  
Polar Orthotropic

AXISYMMETRIC VIBRATION OF POLAR ORTHOTROPIC CIRCULAR PLATES OF QUADRATICALLY VARYING THICKNESS RESTING ON ELASTIC FOUNDATION

2005 ◽  
Vol 05 (03) ◽  
pp. 387-408 ◽  
Author(s):  
N. BHARDWAJ ◽  
A. P. GUPTA
Keyword(s):  
Elastic Foundation ◽  
Ritz Method ◽  
Three Dimensional ◽  
Normal Modes ◽  
Mode Shapes ◽  
Axisymmetric Vibration ◽  
Circular Plates ◽  
Varying Thickness ◽  
Edge Conditions ◽  
Polar Orthotropic

This paper is concerned with the axisymmetric vibration problem of polar orthotropic circular plates of quadratically varying thickness and resting on an elastic foundation. The problem is solved by using the Rayleigh–Ritz method with boundary characteristic orthonormal polynomials for approximating the deflection function. Numerical results are computed for frequencies, nodal radii and mode shapes. Three-dimensional graphs are also plotted for the first four normal modes of axisymmetric vibration of plates with free, simply-supported and clamped edge conditions for various values of taper, orthotropy and foundation parameters.

scholarly journals Modeling and Simulation of Vibrations of Non-Homogeneous Annular Plate of Quadratic Thickness Resting on Elastic Foundation

2020 ◽  
Vol 8 (10S2) ◽  
pp. 61-65
Keyword(s):  
Mathematical Modeling ◽  
Numerical Simulation ◽  
Elastic Foundation ◽  
Natural Frequencies ◽  
Annular Plate ◽  
Thickness Variation ◽  
Quintic Spline ◽  
Form Accuracy ◽  
Varying Thickness ◽  
Edge Conditions

Mathematical modeling is presented to analyze natural frequencies of vibrations of an isotropic annular plate of quadratic varying thickness resting on Winkler type elastic foundation where numerical simulation is carried out using quintic spline technique for three different combinations of edge conditions. Effect of elastic foundation, together with nonhomogeneity variation, on the natural frequencies of vibration is illustrated for variety of thickness variation for the first three modes. To compare parametric effect on a specific plate, transverse displacements are presented in normalized form. Accuracy of the results and validity of numerical method is demonstrated by comparing the existing results in the literature.

Some Results on Axisymmetric Vibration of Spherical Shells of Variable Thickness

1990 ◽  
Vol 112 (4) ◽  
pp. 432-437 ◽  
Author(s):  
A. V. Singh ◽  
S. Mirza
Keyword(s):  
Variable Thickness ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Axisymmetric Vibration ◽  
Spherical Shells ◽  
Varying Thickness ◽  
Wide Range

Natural frequencies and mode shapes are presented for the free axisymmetric vibration of spherical shells with linearly varying thickness along the meridian. Clamped and hinged edges corresponding to opening angles 30, 45, 60 and 90 deg have been considered in this technical brief to cover a wide range from shallow to deep spherical shells. Variations in thickness are seen to have very pronounced effects on the frequencies and mode shapes.

Transverse Vibration of Two Axially Moving Beams Connected by an Elastic Foundation

2005 ◽  
Author(s):  
Mohamed Gaith ◽  
Sinan Mu¨ftu¨
Keyword(s):  
Elastic Foundation ◽  
Transverse Vibration ◽  
Natural Frequencies ◽  
Flexural Rigidity ◽  
Beam Theory ◽  
Mode Shapes ◽  
Winkler Elastic Foundation ◽  
Canonical State ◽  
Axially Moving Beams ◽  
Axially Moving

Transverse vibration of two axially moving beams connected by a Winkler elastic foundation is analyzed analytically. The system is a model of paper and paper-cloth (wire-screen) used in paper making. The two beams are tensioned, translating axially with a common constant velocity, simply supported at their ends, and of different materials and geometry. Due to the effect of translation, the dynamics of the system displays gyroscopic motion. The Euler-Bernoulli beam theory is used to model the deflections, and the governing equations are expressed in the canonical state form. The natural frequencies and associated mode shapes are obtained. It is found that the natural frequencies of the system are composed of two infinite sets describing in-phase and out-of-phase vibrations. In case the beams are identical, these modes become synchronous and asynchronous, respectively. Divergence instability occurs at the critical velocity; and, the frequency-velocity relationship is similar to that of a single traveling beam. The effects of the mass, flexural rigidity, and axial tension ratios of the two beams, as well as the effects of the elastic foundation stiffness are investigated.

Vibration of an Eccentrically Clamped Annular Plate

1993 ◽  
Author(s):  
Jung-Ge Tseng ◽  
Jonathan A. Wickert
Keyword(s):  
Data Storage ◽  
Natural Frequencies ◽  
Annular Plate ◽  
Outer Edge ◽  
Mode Shapes ◽  
Vibration Modes ◽  
Laboratory Measurements ◽  
Free Response ◽  
Amplitude Vibration ◽  
Natural Frequency Spectrum

Abstract Small amplitude vibration of an eccentric annular plate, which is free along its outer edge and clamped along the interior, is investigated through experimental and analytical methods. A disk with this geometry, or a stacked array in which the clamping and symmetry axes of each disk are nominally coincident, is common in data storage and brake systems applications. In the present case, the geometric imperfections on the boundary can have important implications for the disk’s dynamic response. Changes that occur in the natural frequency spectrum, the mode shapes, and the free response under eccentric mounting are studied through laboratory measurements and an approximate discrete model of the plate. The natural frequencies and modes are found through global discretization of the Kamke quotient for a classical thin plate. For the axisymmetric geometry, the natural frequencies of the “sine” and “cosine” vibration modes for a specified number of nodal diameters are repeated. With increasing eccentricity, on the other hand, each pair of repeated frequencies splits at a rate that depends on the number of nodal diameters. Over a range of clamping and eccentricity ratios, the model’s predictions are compared to the measured results.

Vibration analysis of sandwich beams with variable cross section on variable Winkler elastic foundation

2013 ◽  
Vol 20 (4) ◽  
pp. 359-370 ◽  
Author(s):  
Ersin Demir ◽  
Hasan Çallioğlu ◽  
Metin Sayer
Keyword(s):  
Elastic Foundation ◽  
Cross Section ◽  
Natural Frequencies ◽  
Slenderness Ratio ◽  
Sandwich Beam ◽  
Variable Cross Section ◽  
Functionally Graded ◽  
Mode Shapes ◽  
Variable Cross ◽  
Winkler Elastic Foundation

AbstractIn this study, free vibration behavior of a multilayered symmetric sandwich beam made of functionally graded materials (FGMs) with variable cross section resting on variable Winkler elastic foundation are investigated. The elasticity and density of the functionally graded (FG) sandwich beam vary through the thickness according to the power law. This law is related to mixture rules and laminate theory. In order to provide this, a 50-layered beam is considered. Each layer is isotropic and homogeneous, although the volume fractions of the constituents of each layer are different. Furthermore, the width of the beam varies exponentially along the length of the beam, and also the beam is resting on an elastic foundation whose coefficient is variable along the length of the beam. The natural frequencies are computed for conventional boundary conditions of the FG sandwich beam using a theoretical procedure. The effects of material, geometric, elastic foundation indexes and slenderness ratio on natural frequencies and mode shapes of the beam are also computed and discussed. Finally, the results obtained are compared with a finite-element-based commercial program, ANSYS®, and found to be consistent with each other.

Linear Dynamics of a Translating String on an Elastic Foundation

1990 ◽  
Vol 112 (1) ◽  
pp. 2-7 ◽  
Author(s):  
N. C. Perkins
Keyword(s):  
Free Vibration ◽  
Elastic Foundation ◽  
Linear Response ◽  
Natural Frequencies ◽  
Cutoff Frequency ◽  
Forced Response ◽  
Mode Shapes ◽  
Translation Speed ◽  
Linear Dynamics ◽  
Distinct Solution

This paper examines the free and forced linear response of a string which is translating across an elastic foundation. Exact solutions are derived for the free vibration of the string which translates between fixed eyelets and across elastic foundations represented by (1) a single interior spring and (2) a uniform step foundation. Results illustrate the dependence of the string natural frequencies and mode shapes on the foundation stiffness, the foundation geometry, and the string translation speed. The forced response of the string to harmonic end excitation is computed in closed form for the case of a complete uniform foundation. A cutoff frequency separates three distinct solution forms. For excitation frequencies below the cutoff frequency, the response amplitude decays exponentially with distance from the driven end.

Free Vibration of Polar-Orthotropic Sector Plates Resting on Point Supports

1985 ◽  
Vol 107 (3) ◽  
pp. 334-338 ◽  
Author(s):  
Y. Narita
Keyword(s):  
Power Series ◽  
Free Vibration ◽  
Natural Frequencies ◽  
Mode Shapes ◽  
Opening Angle ◽  
Simply Supported ◽  
Annular Sector ◽  
Sector Plate ◽  
Polar Orthotropic ◽  
Double Power Series

An accurate Ritz solution for the free vibration of point-supported annular sector plates of polar orthotropy is presented. A double power series function is used to represent deflection of the plate, with Lagrange multipliers to impose the constraint conditions. To establish accuracy of the approach, the frequency parameters of a sector plate with some supporting points distributed along the boundary are compared to those of a uniformly simply supported plate. The natural frequencies and mode shapes are presented for wide ranges of the opening angle, radius ratio, and orthotropic parameters.

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