Dear All,
Is there Freeware available that would allow the user to make reasonably accurate simulations of loudspeaker cone break-up, including the locations of local cone movement (aka break-up), in relation to cone size, profile, material and cone-termination?
In other words: a poor man's FineCone?
Thanx,
Eelco
Is there Freeware available that would allow the user to make reasonably accurate simulations of loudspeaker cone break-up, including the locations of local cone movement (aka break-up), in relation to cone size, profile, material and cone-termination?
In other words: a poor man's FineCone?
Thanx,
Eelco
There are several options for free FEM software (although they are more complex, than FineCone).
1. Elmer FEM package allows you to solve multiphysics problems.
2. Wolfram Engine + Jupyter Notebook (requires some physics and programming skills).
1. Elmer FEM package allows you to solve multiphysics problems.
2. Wolfram Engine + Jupyter Notebook (requires some physics and programming skills).
Hello Dmitrij,
Thanks al lot for these suggestions.
It is currently all (far) above my head, I am afraid. Do example files related to cone modelling exist?
Thanks al lot for these suggestions.
It is currently all (far) above my head, I am afraid. Do example files related to cone modelling exist?
Modelling is a big part of my job and out of curiosity: how do you get all the data needed for a proper simulation? Like cone density in various areas, e-modul, ... ?
That is a heck of a good question.
To be honest: Although COMSOL e.a. is far above my head, I' m still dreaming of a way to reverse engineer a cone plus suspension assembly but simply measuring SPL and then have the whole assembly decomposed.
To be honest: Although COMSOL e.a. is far above my head, I' m still dreaming of a way to reverse engineer a cone plus suspension assembly but simply measuring SPL and then have the whole assembly decomposed.
Elmer FEM is not as complicated as it may seem at first glance.
Actually, the general workflow is as follows:
1. FreeCAD/Solidworks etc.: You should prepare a step file of your 3D model.
2. GMSH: Import STEP to GMSH and prepare a mesh of your model
3. ELMER FEM: import the mesh file into Elmer GUI and describe all properties needed to run the solver (materials, boundary condition, solvers etc.). Note, that ELMER GUI is only needed to prepare a SIF script file, which is a simple text file with a set of commands, so you can prepare SIF script in any text editor.
4. ParaView: when a problem is solved the postprocessing should be performed. I prefer the PARAVIEW, which is a very powerful postprocessor.
It will definitely take some time to master the modeling process, but each of the above software is well documented and there are tutorials on YouTube.
ELMER Documentation
Index of /index/elmer/doc
If you are newbie with ELMER, it is better to start with this manual
https://www.nic.funet.fi/index/elmer/doc/GetStartedElmer.pdf
(if you will install Elmer and ParaView, don't forget to add Environment Variables to the PATH. I also don't recommend to install the programs to the Program Files folder because UAC sometimes cause troubles)
Elmer GUI Tutorials
https://www.nic.funet.fi/index/elmer/doc/ElmerTutorials.pdf
YouTube tutorial demonstrates ELMER GUI workflow
ElmerGUI 1st tutorial - Temperature distribution of a solid object - YouTube
Various other examples
GitHub - dymaxionkim/ElmerFEM_Examples
https://github.com/ElmerCSC/elmerfem/tree/devel/fem/tests
Example of Acoustic media-Structure interaction
https://github.com/ElmerCSC/elmerfem/tree/devel/fem/tests/HelmholtzStructure
I had a bit of play with the equations for free vibration of plates and I reckon the scaling law for cone breakup frequency is:
sqrt(E t^2 / µ) / (R^2)
ie proportional to (Youngs modulus of cone material)^0.5
proportional to (thickness of cone material)
proportional to (volume density of cone material)^-0.5
proportional to (dimension of cone)^-2 (ie inversely to the area).
So once you've figured out a value for one geometry you can scale it and play with material details without having to recalculate the FEM stuff - although you might want to cross-check this analysis with several FEM runs.
sqrt(E t^2 / µ) / (R^2)
ie proportional to (Youngs modulus of cone material)^0.5
proportional to (thickness of cone material)
proportional to (volume density of cone material)^-0.5
proportional to (dimension of cone)^-2 (ie inversely to the area).
So once you've figured out a value for one geometry you can scale it and play with material details without having to recalculate the FEM stuff - although you might want to cross-check this analysis with several FEM runs.