Difference between revisions of "Category:Floating Elastic Plate"
Line 16: | Line 16: | ||
by the following | by the following | ||
<center><math> | <center><math> | ||
− | \partial_x^2\left(D\partial_x^2 \ | + | \partial_x^2\left(D\partial_x^2 \zeta\right) + \rho_i h \frac{\partial^2 \zeta}{\partial t^2} = p |
</math></center> | </math></center> | ||
where <math>D</math> is the flexural rigidity, <math>\rho_i</math> is the density of the plate, | where <math>D</math> is the flexural rigidity, <math>\rho_i</math> is the density of the plate, | ||
<math>h</math> is the thickness of the plate, <math> p</math> is the pressure | <math>h</math> is the thickness of the plate, <math> p</math> is the pressure | ||
− | and <math>\ | + | and <math>\zeta</math> is the plate vertical displacement. Note that this equations simplifies if the plate has constant |
properties. | properties. | ||
The edges of the plate can satisfy a range of boundary conditions. The natural boundary condition (i.e. free-edge boundary conditions). | The edges of the plate can satisfy a range of boundary conditions. The natural boundary condition (i.e. free-edge boundary conditions). | ||
<center><math> | <center><math> | ||
− | \frac{\partial^2 \ | + | \frac{\partial^2 \zeta}{\partial x^2} = 0, \,\,\frac{\partial^3 \zeta}{\partial x^3} = 0 |
</math></center> | </math></center> | ||
at the edges of the plate. | at the edges of the plate. | ||
If we assume that the pressure is of the form <math>p(x,t) = e^{i\omega t} \bar{p}(x)</math> then it follows that | If we assume that the pressure is of the form <math>p(x,t) = e^{i\omega t} \bar{p}(x)</math> then it follows that | ||
− | <math>\ | + | <math>\zeta(x,t) = e^{i\omega t} \bar{\zeta}(x) </math> from linearity. In this case the equations reduce to |
<center><math> | <center><math> | ||
− | \partial_x^2\left(D\partial_x^2 \bar{\ | + | \partial_x^2\left(D\partial_x^2 \bar{\zeta}\right) -\omega^2 \rho_i h \bar{\zeta} = \bar{p} |
</math></center> | </math></center> | ||
Revision as of 21:42, 6 November 2008
Introduction
The floating elastic plate is one of the best studied problems in hydroelasticity. It can be used to model a range of physical structures such as a floating break water, an ice floe or a VLFS). The equations of motion were formulated more than 100 years ago and a discussion of the problem appears in Stoker 1957. The problem can be divided into the two and three dimensional formulations which are closely related. The plate is assumed to be isotropic while the water motion is irrotational and inviscid.
The solution methods are divided up into those for Two-Dimensional Floating Elastic Plate and those for a Three-Dimensional Floating Elastic Plate.
Linear Thin Elastic Plate Theory
We present here the theory of an elastic plate in a vacuum, concentrating of the two-dimensional problem.
For a Bernoulli-Euler Beam on the surface of the water, the equation of motion is given by the following
where [math]\displaystyle{ D }[/math] is the flexural rigidity, [math]\displaystyle{ \rho_i }[/math] is the density of the plate, [math]\displaystyle{ h }[/math] is the thickness of the plate, [math]\displaystyle{ p }[/math] is the pressure and [math]\displaystyle{ \zeta }[/math] is the plate vertical displacement. Note that this equations simplifies if the plate has constant properties.
The edges of the plate can satisfy a range of boundary conditions. The natural boundary condition (i.e. free-edge boundary conditions).
at the edges of the plate.
If we assume that the pressure is of the form [math]\displaystyle{ p(x,t) = e^{i\omega t} \bar{p}(x) }[/math] then it follows that [math]\displaystyle{ \zeta(x,t) = e^{i\omega t} \bar{\zeta}(x) }[/math] from linearity. In this case the equations reduce to
Linear Elastic Thin Plate on Water
We begin with the linear equations for a fluid. The kinematic condition is the same
but the dynamic condition needs to be modified to include the effect of the the plate
We also have Laplace's equation
and the usual non-flow condition at the bottom surface
where [math]\displaystyle{ \zeta }[/math] is the surface displacement, [math]\displaystyle{ \Phi }[/math] is the velocity potential, and [math]\displaystyle{ \rho }[/math] is the fluid density.
Nonlinear Elastic Thin Plate on Water
The nonlinear plate equations can be found by include We begin with the nonlinear equations for a fluid. The kinematic condition is
the dynamic condition is
There are different versions of the nonlinear boundary condition for a plate and this one is based on Parau and Dias 2002. We also have Laplace's equation
and the usual non-flow condition at the bottom surface
Pages in category "Floating Elastic Plate"
The following 15 pages are in this category, out of 15 total.
E
- Eigenfunction Matching for a Circular Floating Elastic Plate
- Eigenfunction Matching for a Finite Floating Elastic Plate using Symmetry
- Eigenfunction Matching for a Semi-Infinite Floating Elastic Plate
- Eigenfunction Matching Method for Floating Elastic Plates
- Elastic Plate on Shallow Water
- Energy Balance for Two Elastic Plates