Vibrations of orthotropic square plates having variable thickness (linear variation)
TL;DR: In this article, the effect of fiber orientation on the natural frequencies of thin square orthotropic plates having variable thickness was studied using the Rayleigh-Ritz method for various boundary conditions.
About: This article is published in Composites.The article was published on 1988-11-01. It has received 6 citations till now. The article focuses on the topics: Orthotropic material.
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9 citations
TL;DR: In this article, a finite element formulation for vibration analysis of rotating laminated composite panels is employed; based on the first order shear deformation theory, an accurate relationship between strains and displacements of pre-twisted panels are derived.
4 citations
Journal Article•
TL;DR: In this paper, the thermal effect on the vibration of a non-homogeneous square plate of variable thickness having clamped boundary was studied and the Rayleigh Ritz technique was used to calculate the natural frequency for both the modes of vibration for the various values of taper parameter, nonhomogeneity constant and thermal gradient.
Abstract: Vibrations of plate and plate type structures made up of composite materials have a significant role in various industrial mechanical structures, aerospace industries and other engineering applications. The main aim of the present paper is to study the two dimensional thermal effect on the vibration of non-homogeneous square plate of variable thickness having clamped boundary. It is assumed that temperature varies bi-parabolic i.e. parabolic in x-direction & parabolic in y-direction and thickness is considered to vary exponentially in x direction. Also, density is taken as the function of “x” due to non-homogeneity present in the plate’s material. Rayleigh Ritz technique is used to calculate the natural frequency for both the modes of vibration for the various values of taper parameter, non-homogeneity constant and thermal gradient. All the calculations are carried out for an alloy of Aluminum, Duralumin, by using mathematica.
4 citations
Dissertation•
01 Jan 1990
TL;DR: In this paper, the effect of stiffeners on the dynamic properties of a plate has been investigated and it has been shown that most of the increase in frequency and critical buckling load was directly related to the increase of stiffness of the stiffener and its position on the plate structure.
Abstract: Vibration and stability studies have been undertaken on glass fibre reinforced polymer composite unstiffened and stiffened plates to optimise their dynamic properties. Boundary conditions, stiffeners and orthotropy of the material add to the complexity of a mathematical solution and to overcome this problem experimental and analytical studies were undertaken. The former method was carried out by impact hammer and an FFT digital signal analyser and the latter method was undertaken using finite element computer software. The current research concentrated upon the procedures and possible techniques available to optimise the dynamic properties of the plate without introducing weight penalty with the object of achieving an efficient structural performance coupled with an economic design. It has been shown that most of the increase in frequency and critical buckling load was directly related to the increase in stiffness of the stiffener and its position on the plate structure. The mode shapes have provided information regarding the most advantageous position for the setting of the stiffeners; they must be positioned away from nodal lines. The effect of the stiffener was significant for the fully clamped and clamped/free plates where only bending modes of vibration are present. However, for the completely free plates, where both bending and torsional modes of vibration could occur, the effect that the stiffeners have on the torsional modes was minimal. To locate precisely the position of the stiffener may be difficult when the plates are subjected to in-plane compressive loads, because higher order mode shapes may interchange. The mass-saving advantage which has been obtained in this research has shown that the stiffened plates with top-hat stiffeners were seen to have higher natural frequencies, within a specific vibration mode, compared to stiffened plates with rectangular stiffeners (blade).
3 citations
Cites methods from "Vibrations of orthotropic square pl..."
...A Rayleigh-Ritz formulation was used by the previous investigators [46] to study the effect of fibre orientation and boundary conditions on the fundamental frequency of a square graphite/epoxy plate of variable thickness (linear variation) along the x-direction and the y-direction....
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Journal Article•
TL;DR: In this article, the closed form analytical expressions for the displacement field due to a cylindrical inclusion in a thermoelastic half-space are derived in the context of steady-state uncoupled thermo-elasticity using the displacement potential functions.
Abstract: In this paper, the closed form analytical expressions for the displacement field due to a cylindrical inclusion in a thermoelastic half-space are obtained. These expressions are derived in the context of steady-state uncoupled thermoelasticity using thermoelastic displacement potential functions. The thermal displacement field is generated due to differences in the coefficients of linear thermal expansion between a subregion and the surrounding material. Further, comparison between displacement field in a half-space and in an infinite medium has been discussed. The variation of displacement field in a half-space and its comparison with an infinite medium is also shown graphically.
2 citations
References
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01 Jan 2008
TL;DR: The combination of materials to form a new material system with enhanced material properties is a well documented historical fact as discussed by the authors, which is why many artisans from the Mediterranean and Far East used a form of composite technology in molding art works which were fabricated by layering cut paper in various sizes for producing desired shapes and contours.
Abstract: The combination of materials to form a new material system with enhanced material properties is a well documented historical fact. For example, the ancient Jewish workers during their tenure under the Pharaohs used chopped straws in bricks as a means of enhancing their structural integrity. The Japanese Samurai warriors were known to use laminated metals in the forging of their swords to obtain desirable material properties. Even certain artisans from the Mediterranean and Far East used a form of composite technology in molding art works which were fabricated by layering cut paper in various sizes for producing desired shapes and contours.
3,908 citations
Book•
01 Jan 1980
TL;DR: In this paper, the authors present a reference record created on 2005-11-18, modified on 2016-08-08 and used for Laminage Reference Record created on 2006-11/18.
Abstract: Keywords: materiaux : composites ; elasticite ; contraintes ; cisaillement ; traction ; isentropie ; laminage Reference Record created on 2005-11-18, modified on 2016-08-08
1,953 citations
TL;DR: In this paper, the effect of fibre orientation on the fundamental frequency of thin rectangular/square orthotropic plates was studied using a high precision triangular orthotropic finite element, which is useful in studying plates of arbitrary plan form and arbitrary fibre orientation.
17 citations