Tag for the usage of "FiniteElement" Method embedded in NDSolve and implementation of finite element method (fem) in mathematica.

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3
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1answer
85 views

Use FEM Solver for System of Nonlinear PDEs with Nonlinear Coefficients - Reaction-Diffusion

I am trying to solve a complex transient reaction-diffusion problem numerically in 2D. Let's take a simple system to start, say $$ A+B\rightarrow C \\ C \rightarrow A+B $$ with reaction rate $k_1$ ...
2
votes
1answer
73 views

ToElementMesh fails on DodecahedronIcosahedronCompound

Context I would like to compute the eigenmodes of a DodecahedronIcosahedronCompound. Why? Because it is cool! and I wonder how it rings… Starting with: ...
5
votes
0answers
70 views

How to create an ElementMesh of a Sphere

I want to create an ElementMesh of a "sphere". To reduce the computational effort I want to use HexahedronElement; the ...
1
vote
0answers
59 views

How to Implement a “Function Object” suitable for NDSolve and Finite Element Method?

I have a bunch of methods that shoud return an expression that behave like a function, i.e. an expression that, when supplied with suitable arguments, evaluate to something. A simple ...
5
votes
0answers
65 views

Kernel Crash while using “ValuesOnGrid” method of InterpolatingFunction

I was experiencing some kernel crash while using "ValuesOnGrid" method of an InterpolatingFunction returned by ...
6
votes
1answer
180 views

3D FEM with holes

I'm trying to create a finite element mesh with some spherical holes. To my mind the behavior is erratic but generally fails. I'm using MMA 10.0.2. In the following 3 different sets of holes are ...
1
vote
1answer
94 views

Generating a boundary mesh from a list of points

I have a list of points from which I am trying to generate a mesh: ...
35
votes
2answers
757 views

Numerically solving Helmholtz equation in 3D for arbitrary shapes

Context While studying manifold Learning I got interested in finding the eigenvectors of the Laplacian. (also in connection to this problem of solving the heat equation) Following this and that ...
15
votes
1answer
202 views

Eigenfunctions of the Laplacian on an arbitrary mesh

So, I've constructed a mesh over which I'd like to find eigenfunctions of Laplace's equation with a free boundary (a zero Neumann boundary condition along the edge). Mostly because I figured an ...
2
votes
1answer
77 views

Solving a time-dependent structural mechanics problem with Finite Element

I'm trying to solve a time-dependent structural mechanics problem with Finite Element. I modified one of the last samples in the "Solving Partial Differential Equations with Finite Elements" Tutorial. ...
2
votes
0answers
117 views

Choosing FEM element type and mesh refinement

I have only recently been introduced to Mathematica's(v10.0) FEM capabilities. I understand that for solving PDEs on non-uniform shapes via NDSolve, Mathematica ...
2
votes
1answer
65 views

ToElementMesh[]

Could you please help with the following: ...
5
votes
0answers
108 views

NDSolve computes wrong solution?

Please excuse me if the question has already been answered somewhere else, but I was not able to find it. Could somebody tell me what I am doing wrong here? The solution of DSolve is of course correct ...
9
votes
2answers
174 views

Build an InterpolatingFunction with ElementMeshInterpolation

Suppose you have a function f[t_, x_, y_] := t (1 - x^2 - y^2) defined for {x,y} in ...
2
votes
0answers
70 views

FEM in Mathematica and AceGen

I just wanted to ask, if anybody has already worked with AceGen AceGen, Wolfram Research AceGen, Homepage and knows what clear advantages AceGen has compared to the new FEM in Mathematica 10 ...
5
votes
1answer
182 views

FEM: user material subroutines (UMAT in ABAQUS), mechanics

Just a quick question (mainly for those who are also familiar with ABAQUS or other comparable FEM programs and non-linear modelling of mechanical behavior, e.g., plasticity). Is there any module in ...
5
votes
2answers
171 views

Kernel quits without error in NDSolveValue

I am using the latest 10.1. The following single line command makes the kernel quit without error message (just a beep): ...
11
votes
0answers
124 views

MinMax function (Mathematica v10.1.0) conflicts with NDSolve`FEM`MinMax?

Some problem in v10.1.0 (Windows 8.1 x64) and the new MinMax... ...
3
votes
1answer
69 views

Problem with MeshOrderAlteration to create a 2nd order ElementMesh

After working on this 2D domain, I'm trying to reproduce the same ideas to create a mesh of a sphere composed of QuadElement, instead of more simple and common ...
5
votes
1answer
126 views

NDSolve and FEM support for non conformal meshes of a disk [with Kernel crash]

I want to create an ElementMesh for a disk. For my specific scenario, some author advise to use a regular mesh, where the radial and tangential directions are ...
1
vote
0answers
47 views

Error message for FEMStiffnessElements

I am trying to solve this pde numerically with Mathematica: ...
8
votes
1answer
210 views

FEM: how to choose FEM element type

I am asking myself if there is any simple option for choosing the element type for the mesh generation WITHOUT explicitly creating coordinates and then the mesh. Minimal example: here I would like ...
1
vote
1answer
137 views

PDE solution does not satisfy Neumann boundary conditions using NDSolve

I am trying to solve the free particle Schrodinger equation in 1D (hbar =1, Energy = 1, mass = 1), But specifying conditions only on x==0: ...
4
votes
2answers
103 views

Join Two Element Meshes

Let's say I have two element meshes defined as the following: ...
9
votes
2answers
225 views

Solve a PDE over a region defined by a Bezier patch

I am using NDSolve to find the solution to a PDE over an arbitrary domain. The domain is specified by a Bezier patch. ...
6
votes
1answer
135 views

Long running ToElementMesh with very “large” domains

I'm trying to solve a system of PDE over a large domain. This doesn't means I need to have a huge amount of mesh points and mesh elements to discretize the domain. Just that the domains has a big ...
8
votes
1answer
455 views

FEM - how should I impose periodic boundary conditions in pure space problems?

I have searched other threads, but I was not successful in finding an answer I could understand. Right to the point: how do I impose correctly periodic behavior on the edges of the rectangular ...
3
votes
2answers
128 views

BUG: Problems generating FEM ElementMesh in 1-D

fixed in 10.1 (windows) I'm trying to build an ElementMesh for a simple 1-D problem. First, I build the boundary ...
1
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0answers
99 views
1
vote
1answer
87 views
9
votes
4answers
378 views

How discretize a region placing vertices on a specific non-uniform grid

Given a generic region, for example: Ω = ImplicitRegion[ 2 x^2 + 3 y^2 + 2 x y - 2 <= 0 ∧ x^2 + y^2 > .1, {x, y}]; and a non-uniform grid, for ...
3
votes
1answer
214 views

Trouble understanding NeumannValue and Inactive/Formal PDEs

I read all documentation about the Finite Element Method in Mathematica 10, and I read some questions here, but I'm still unable to properly understand how to use the ...
10
votes
1answer
364 views

representation of custom deformation on a meshgrid

I am trying to represent 2D deformations on a rectangular grid. In Mathematica 10, there is a method to solve the elastic differential equations and then represent the deformation as presented here: ...
3
votes
0answers
51 views

Missing links in usage statements

The integration of the documentation center does not seem to be complete on my machine. I often access the documentation center via the usage statement links. ...
7
votes
1answer
230 views

Problem with Neumann condition in quarter disc

Bug persists through version 10.1 So I'm following the available examples in version 10 for FEM, The plane stress operator is shown as this ...
11
votes
2answers
442 views

How to create subregions for the NDSolve FEM Solver

I am trying to create a 2d region consisting of two subregions. The inner region has several holes, where boundary conditions are applied. The figure shows the idea. I have tried to create this ...
2
votes
0answers
112 views

Puzzling NDSolve[] behavior for PDE (smooth solution, inconsistent with boundary conditions)

Consider the following: NDSolve[{D[z[x, y], x, x] + D[z[x, y], y, y] == 0, z[x, 0] == Sin[x], z[0, y] == Cos[y]}, z[x, y], x, y] {{z[x, y] -> ...
2
votes
0answers
213 views

How to solve a PDE with Robin Boundary Condition inside considered region?

I'm trying to solve the heat diffusion equation in cylindrical coordinates. The main problem is that I would like to include the Robin Boundary Condition inside considered region in order to simulate ...
2
votes
0answers
386 views

How to solve a nonlinear coupled PDE with initial and some boundary values

I would like to solve the following nonlinear coupled PDE with a mix of initial conditions and boundary values: ...
25
votes
1answer
897 views

Calculating a potential function using the finite element method

This is my first attempt to use the Finite Element method available in version 10. There are questions and I am very open to suggestions. My example is flow around a cylinder which is a well known ...
1
vote
0answers
68 views

Error when extending 1-dimensional PDE to 2 dimensions

I want to calculate how magnetic flux is trapped in a superconductor near the interface superconductor/vacuum. This problem already was solved analytically by J. Pearl for cylindrical symmetry (if ...
10
votes
2answers
518 views

FEM: Nicer Element Shape for Spherical Region

I'm trying to generate a mesh for later use in the Finite Element Method of the DSolve command. It is basically a parallelepiped with a spherical indentation. I'm ...
0
votes
0answers
59 views

How to set the boundary fixed and apply the Young's modulus in Mathematica's FEM? [duplicate]

Provided the drawing .stl is given, and the Young's modulus is know, how to start a FEM vibration mode test in Mathematica? The boundary is required to be fixed and the interested focus is on the ...
1
vote
1answer
742 views

Test a wooden board's vibration mode

Here is a wooden board, with dimensions shown on the picture below. How we can use Mathematica's newly build-in finite element analysis features to show the different modes of its vibrations. Assuming ...
1
vote
1answer
848 views

Solving a nonlinear PDE with Mathematica10 FEM Solver

I am trying to solve a system of coupled nonlinear PDEs in a rectangular region with the new FEM solver in Mathematica 10. However, I come across an error stating NDSolveValue::femnonlinear: ...
46
votes
2answers
3k views

Numerically solving Helmholtz equation in 2D for arbitrary shapes

I would like to solve the Helmholtz equation with dirichlet boundary conditions in 2 dimensions for an arbitrary shape. (for a qualitative comparison of the eigenstates to periodic orbits in the ...
3
votes
0answers
176 views

Nonlinear FEM and FindRoot

I'm trying to develop a kind of nonlinear FEM application using mathematica to solve a bvp like the following: $$ \gamma(u') ~u^{iv} + 2 \gamma'(u') u''' u''+ u''^3 = f(x) $$ where $u = ...
14
votes
4answers
1k views

How do I solve a PDE with a strange boundary condition?

How do I solve the PDE with boundary value like this $$u(t,x,y)=0, \textrm{when } F(x,y)=0$$ using DSolve? As a specific example, I want to solve heat equation $$\frac{\partial u}{\partial ...