Kratos Magnetostatic Application

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Revision as of 16:30, 1 February 2010

General Description

The KRATOS Magnetostatic Application deals with the Finite Element Analysis of problems in magnetostatics. Though the mathematics and general formulation is quite similar to Electrostatics, Magnetostatics presents important differences at a conceptual and a programming level. Therefore, if you are a beginner in electromagnetism or programming electromagnetic applications, we strongly recommend you that you first start with the Electrostatic application.

The following description of the Kratos Magnetostatic Application takes part of:

general concepts in electromagnetism;
the Finite Element Method applied to the electromagnetism;
the use of Kratos for basic problems;

At a first glance, it could be said that Electrostatics works with static charges whereas Magnetostatics does it with dynamic charges (or static currents). That's partially true and we avoid by now to

, but we are going to consider Magnetostatics as a completely new phenomena instead of thinking in a kind of electrodynamics.

Magnetostatics

Electrostatic establishes the most basic principles of the Maxwell equations and it is excellent to work at academic level. Nevertheless, some serious industrial applications can be solved by using just these simplest equations and simulation program (circuit components such as condensers and bipolar diodes, electrical field distribution for high voltage systems, etc).

Theory

Magnetostatics[1][2][3] refers to the physical phenomena related to the presence of electric charges in the objects.

Basic principles

Our first Maxwell's equation:

$\vec{\nabla}\cdot\vec{D} = \rho$

where:

$\vec{D} = \varepsilon\vec{E} = \varepsilon_0\varepsilon_r\vec{E}$

with: $\varepsilon, \varepsilon_0, \varepsilon_r$ the permittivity of the medium, of the free space and relative permittivity, respectively.

The electric field is the gradient of an electrostatic potential ( $V [Volts]\,$ ):

$\vec{E}=-\vec{\nabla} V$

Our second Maxwell's equation:

$\vec{\nabla}\times\vec{E} = 0$

By combining these Maxwell's equations, we can easily can obtain the Poisson's equation:

$\vec{\nabla} \varepsilon \vec{\nabla} V + \rho_v = 0$

Basic principles extended

Poisson's Equation in Magnetostatics

The detailed form of the Poisson's Equation[9] in Magnetostatics is:

$\frac{\partial}{\partial x}\cdot \left( \varepsilon_{x} \cdot \frac{\partial V(x,y,z)}{\partial x}\right) + \frac{\partial}{\partial y}\cdot \left(\varepsilon_{y} \cdot \frac{\partial V(x,y,z)}{\partial y} \right) + \frac{\partial}{\partial z}\cdot \left(\varepsilon_{z} \cdot \frac{\partial V(x,y,z)}{\partial z} \right) + \rho_v(x,y,z)=0$

Poisson's Equation extended

Magnetostatic Boundary Conditions

For a domain ${\Omega} \,$ , we should consider three different boundary conditions:

Dirichlet boundary condition:

$\left . V - \bar V = 0 \right |_{\Gamma_{V}}$

Neumann boundary condition:

$\left . \hat n \vec{D} - \bar D_n = 0 \right |_{\Gamma_{q}}$

Infinit condition (when no physical boundary are presents -free space-):

$\left . \frac{\partial V}{\partial r} \right |_{\Gamma_{\infty}} \approx - \frac{V}{r}$

Boundary Conditions extended

References

The Finite Element Method for Magnetostatics

Using the Application

@@ Line 1: / Line 1: @@
 == General Description ==
-The [[Kratos | KRATOS]] Electrostatic Application deals with the Finite Element Analysis of problems in [http://en.wikipedia.org/wiki/Electrostatics '''electrostatics''']. It can be considered the most basic problem in [http://en.wikipedia.org/wiki/Electromagnetism electromagnetism] and it use to be the first chapter in the introductory books about electromagnetism.
+The [[Kratos | KRATOS]] Magnetostatic Application deals with the Finite Element Analysis of problems in [http://en.wikipedia.org/wiki/Magnetostatics '''magnetostatics''']. Though the mathematics and general formulation is quite similar to Electrostatics, Magnetostatics presents important differences at a conceptual and a programming level. Therefore, if you are a beginner in electromagnetism or programming electromagnetic applications, we strongly recommend you that you first start with the [[Kratos_Electrostatic_Application |Electrostatic application]].
-Therefore, the following description of the '''Kratos Electrostatic Application''' can be used as an introduction to:
+The following description of the '''Kratos Magnetostatic Application''' takes part of:
 * general concepts in [http://en.wikipedia.org/wiki/Electromagnetism '''electromagnetism'''];
 * the [http://en.wikipedia.org/wiki/Finite_element_method '''Finite Element Method'''] applied to the electromagnetism;
 * the use of Kratos for basic problems;
+At a first glance, it could be said that Electrostatics works with static charges whereas Magnetostatics does it with dynamic charges (or [http://en.wikipedia.org/wiki/Electric_current static currents]). That's partially true and we avoid by now to
-<!-- It covers 2D and 3D calculations in linear and nonlinear static and dynamic structural mechanics. Additional [[Utility | utilities]] are capable of considering [[Contact | contact]] problems, the deactivation and reactivation of elements and a large number of boundary conditions.
+, but we are going to consider Magnetostatics as a completely new phenomena instead of thinking in a kind of electrodynamics.
--->
+Magnetostatics
 Electrostatic establishes the most basic principles of the Maxwell equations and it is excellent to work at academic level. Nevertheless, some serious industrial applications can be solved by using just these simplest equations and simulation program (circuit components such as condensers and bipolar diodes, electrical field distribution for high voltage systems, etc).

Kratos Magnetostatic Application

Revision as of 16:30, 1 February 2010

Contents

General Description

Theory

Basic principles

Poisson's Equation in Magnetostatics

Magnetostatic Boundary Conditions

References

The Finite Element Method for Magnetostatics

Using the Application

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