Elmer Discussion Forum

All, I've analyzed an aluminum tuning fork in the free free state to determine how well the Elmer predicted natural frequencies match up with real life. Results are accurate to within 3% of measured frequencies. See files attached, and my full explanation here: http://justinablack.com/tuning_fork_fr...

Has anyone performed a structural harmonic analysis? I'm looking for a simple test case on something like a cantilevered beam. My ultimate goal is to do a frequency sweep and show amplitude vs frequency. I didn't find any test cases covering this in the Elmer files, and I wasn't able to figure out h...

Would adding damping make this problem converge more easily?
That way the max amplitude should be discrete, right?

I used second order tetrahedra for the model (quadratic).
I don't think the air impacts these frequencies.
The fundamental mode for free-free was the tone the tuning fork was supposed to generate. (3% error real life vs analysis)
So I don't think the air impacts it much.

Hello, I'm trying to run a test case correlating Elmer's predicted natural frequencies of a part to real life. I'm using a aluminum tuning fork that I bought off amazon.com. --------------------------------------------- FREE-FREE STATE, Agrees well --------------------------------------------- In fr...

The above poster is correct. The freeze scaling anchors the coordinate system so the zero displacement location stops wagging.
See the attached screen capture showing where the freeze scaling button is in the gui.

Jonathan, I posted my freecad model, brep geometry file, gmsh mesh file, and the elmer model files.
They're in a zip file at the bottom of my post on my webpage:
http://justinablack.com/calculating-the ... m-2014-02/

Hello, I'm plotting the mode shape of a cantilevered beam. But when I animate it, the fixed end is moving. Is anyone else having this problem? See the attached project folder zipped, and my mpeg video showing the problem. Does anyone know how to fix this? I'm using .001 scale when animating. I'm run...

Everyone, please make sure you use second order elements when you're doing eigenvalue analysis per the poster's comments above. I've analyzed a cantilevered beam using 1st order and 2nd order tetrahedral elements, and the error inherent in using first order elements is huge. You can see my work here...

Has anyone had Gmsh import problems? I'm loading in a volume meshed with second order hexahedron elements. The elements load in fine, but my surfaces are not selectable. My methodology: load in brep file add 1 volume physical group Gmsh mesh part 1d 2d 3d Automatic 2D Alg Delaunay 3D Alg Blossom 2D ...