Linked Questions

0 votes
0 answers
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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 ...
Putterboy's user avatar
  • 4,641
80 votes
3 answers
10k views

Numerically solving Helmholtz equation in 2D for arbitrary shapes

I would like to solve the Helmholtz equation with Dirichlet boundary conditions in two dimensions for an arbitrary shape (for a qualitative comparison of the eigenstates to periodic orbits in the ...
Julian S.'s user avatar
  • 1,018
50 votes
2 answers
9k views

How to build a bvh (a motion capture file format) player in Mathematica?

How to build a bvh player that can be used to visualize human motions in Mathematica? Any idea or sample code would be appreciated. ...
Putterboy's user avatar
  • 4,641
54 votes
2 answers
4k 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 ...
chris's user avatar
  • 22.8k
22 votes
2 answers
887 views

Getting rid of spikes in the PDE solution

Bug introduced in 10.0 and fixed in 10.3 Note: In 10.0, Rationalize[fd, 0] was needed or mesh generation would fail. Preamble: I am solving a PDE in a domain ...
Alexei Boulbitch's user avatar
18 votes
1 answer
815 views

Plotting the eigenmodes of a cylindrical shell

There are many examples of eigenmodes computations for surfaces with Mathematica, such as: https://www.wolfram.com/mathematica/new-in-10/pdes-and-finite-elements/solve-a-wave-equation-in-2d.html, ...
anderstood's user avatar
  • 14.3k
11 votes
1 answer
622 views

Finite element boundary breaking

I am trying to model a cantilever beam which can vibrate. On the left the beam is clamped. I am largely following user21 here and also the example in help. I start by doing a static beam which works ...
Hugh's user avatar
  • 16.2k
4 votes
1 answer
2k views

Finite Element Mass and Stiffness Matrices

I am attempting to use the finite element method to solve a vibration problem. I am following user21's answer from here which is very helpful. My problem is that I am confused by the use of the mass ...
Hugh's user avatar
  • 16.2k
9 votes
1 answer
675 views

Gaining precision/accuracy with NDEigenvalues

See further down for an important note Background I study (one component of) the semi-classical Pauli operator, $$ P_h=-h^2\Delta+ih(-y,x)\cdot\nabla+\frac{x^2+y^2}{4}-h. $$ For this particular ...
mickep's user avatar
  • 487
7 votes
1 answer
712 views

NDEigensystem for structural vibration

Having installed version 11 I thought I would check an old Stack Exchange vibration problem using NDEigensytem. The old problem was Test a wooden board's vibration mode and I think this was before ...
Hugh's user avatar
  • 16.2k
3 votes
1 answer
559 views

Finite Element Method fails to give symmetric stiffness matrix for small element size

In a previous post here a method for getting the matrices from a finite element analysis were developed. I am now using this method and it works for large elements but not for small elements. My ...
Hugh's user avatar
  • 16.2k
3 votes
0 answers
804 views

Increasing MaxPoints in NDSolve results in memory issue

I am interested in increasing "MaxPoints" in NDSolve's "MethodOfLines" in attempt to increase the resolution of the plot of the solution of linearly damped wave equation with transparent boundary ...
soccerboyz9341's user avatar
0 votes
0 answers
91 views

To obtain eigenvalues and eigenvectors from FEM solution

I have a model which solve a 2D coupled elasticity problem. Now I'm trying to get the eigenvalues and eigenvector from that solution. But, following the very first step to get stiffness and load ...
Riobaldo Tatarana's user avatar