Simulation error

November 8, 2012, 1:51 pm

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Hi ,

I am getting this type of error whey i am trying to start simulation.

"Variables property does not include all variables in Xmesh"

Could anybody can give me any solution/ suggestion.

Thank you
Sanjay

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Electrostatics + Metal Electrode

June 25, 2010, 4:11 am

≫ Next: Remeshing of Deformed Geometry

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Hello

I'm completely new to comsol. I'm trying to simulate the electric field between some specifically arranged metal electrodes. Between them is some material with a certain permittivity.

Now I get an error because there is no permittivity (epsilon) defined for the metal regions. Of course the metal part should have theoretically infinite permittivity. So I tried entering a very large number there but I'm not sure that this is the proper way to handle it. Is there some other model that should be used for simulation of the metal parts?

Remeshing of Deformed Geometry

July 5, 2012, 2:15 am

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There's a deforming part in a geometry with an edge moving downsides and the others hoding their position.
After I defined the free deformation part and prescribed the mesh velocity, and run the model.
I can't satisfy with the result, the region connected to the unreformed parts are distort too much.
So how to re mesh the deforming mesh to couple with the deforming geometry during the calculation?

Simulation error

November 8, 2012, 7:51 am

≫ Next: transformer model

≪ Previous: Remeshing of Deformed Geometry

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Hi ,

I am getting this type of error whey i am trying to start simulation.

"Variables property does not include all variables in Xmesh"

Could anybody can give me any solution/ suggestion.

Thank you
Sanjay

transformer model

November 14, 2013, 2:31 am

≫ Next: A SMALL DOUBT ON PORT POWER VALUE !

≪ Previous: Simulation error

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Hi everyone,

I am very new to COMSOL, thats why I ask for so basic things. I am going to do simply transformer model with radiation. Firstly I did the model in Inventor. But i have many errors during meshing. My question is whether my model is done wrong or i should not mesh it automatically but in another way?

Second question what type of physics should I use? My idea is to set the temperature of core then set parameters of materials and oil and and notice the temperature distribution in oil? Is that possible at all?

It it had work out, then I would add radiation system to my model.

Please, help:)

Best regards

A SMALL DOUBT ON PORT POWER VALUE !

November 18, 2013, 9:41 pm

≫ Next: name of the element

≪ Previous: transformer model

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Hi all,

I am new to this software and I am trying to simulate a multi-layer structure on which plane electromagnetic wave is allowed to fall at normal incidence. I kept the port power at the default value(1 W) and after running the program I tried to check the power at the port 1. For that I use line integration to calculate sqrt(emw.Poavy^2 +emw.Poavx^2), but to my surprise the values I am getting is smaller than 1.

Can any one help me.
Thanks in advance...

name of the element

November 25, 2013, 5:23 pm

≫ Next: Problem to converge a Reaction engineering, Diluted species transport and laminar flow coupled system.

≪ Previous: A SMALL DOUBT ON PORT POWER VALUE !

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Hello everyone,

I am working on a 3D model where each element has a specific permeability value, given in an excel sheet. Does anyone know how I can assign these values to my elements? One possibilities comes to my mind:


1. Import the excel sheet as a separate function, say, x=<number of the element> & F(x)=<value of the permeability>

2. in the subdomain write F(number of the element) for permeability.

.... Does anyone know how I can have the name of the element in COMSOL?

Problem to converge a Reaction engineering, Diluted species transport and laminar flow coupled system.

November 26, 2013, 11:06 pm

≫ Next: FSI rotating mesh

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I want to degrade one component in a 3D geometry along with diluted species transport and laminar flow in it. My simulation runs okay in stationary study (i used step function here). But when i want to use time dependent study on 3D it shows many errors and failure to find initial values or failure to evaluate variables.

I was wondering that, may be i have used a wrong solver. The concentrations of the species in reaction engineering works easily with time dependent study but i am unable to converge when i synchronize with mass and momentum.

So this time i thought of using time dependent,fixed geometry as my solver. and it is taking infinite time to solve. Am i following the currect way? Is it possible to solve with time dependent fixed geometry? as i used 3d geometry for my laminar flow and tranport diluted species.

FYI: I am using 4.2v of COMSOL.

Please contribute your comsol knowledge. I will be grateful.

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FSI rotating mesh

November 27, 2013, 2:51 am

≫ Next: Two electrodes, four layers

≪ Previous: Problem to converge a Reaction engineering, Diluted species transport and laminar flow coupled system.

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Hi everyone,

I'm trying to simulate a rotating object inclined in a laminar flow with the FSI physics. I managed to rotate an object with a body load, but it causes a lot of remeshing.

The rotating machinery physics deals with this problem by using a rotating mesh and a flow continuity boundary condition between the stationary and the rotating domain. I tried the same in the FSI physics but the continuity boundary condition produces "failed to evaluate... k_stress_tensor_testYX ".

Thanks for your help!
Moritz

Two electrodes, four layers

December 2, 2013, 12:39 am

≫ Next: Ghost domain, bug?

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Hi everyone!

I am trying to do simple model using 3D Comsol Multiphysics // AC/DC module // Quasi Statics, electric // time harmonic analysis ... two electrodes, 0.5V and -0.5V, four skin layers with permitivity and conductivity. Temporarily I am using stationary solver, when this will work, the model will be updated with time dependant solver and new voltage (+/- 0.5*sin(2*pi*f*t[1/s])).

However, the problem is that voltege drop is only through first layer and only under the electrodes. I was expacting drop through all layers in all directions. What am I doing wrong? The model is attached below ...

Please help, thank you very much!

Ghost domain, bug?

December 3, 2013, 12:36 am

≫ Next: comb drive actuator

≪ Previous: Two electrodes, four layers

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I have a curious problem with Comsol (4.3b and 4.4) with ghost domains.
If i look at the geometry and select all domains, i have, ie 10 domains.
When assigning materials, then the 11th domain appears mysteriously, and of course, I cannot run the simulation.

comb drive actuator

December 3, 2013, 10:59 pm

≫ Next: comsol error failed to evaluate variable

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I am trying to simulate a basic comb drive actuator in comsol.
The electrostatic force in y-direction is coming negative,although it should come positive.
Kindly help me out as soon as possible.
I have attached the model.

comsol error failed to evaluate variable

December 4, 2013, 12:22 am

≫ Next: Large mesh with Beam Envelopes module

≪ Previous: comb drive actuator

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Hi,

i am trying to design spiral inductor using the physics "magnetic and electricfield(mef)
but i have this error

Failed to evaluate variable
- Variable : mf.normB
- Geometry: 1
- Domain: 2 3 4 5 6
failed to evaluate expression
expression:mf.normB
plot:mscl(multislice)

see the attached file.

Can any one help me, please ?

thanks.

Large mesh with Beam Envelopes module

December 4, 2013, 5:54 am

≫ Next: Mesh Problem

≪ Previous: comsol error failed to evaluate variable

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Dear all,

probably I'm missing something about the use of the Electromagnetic Waves, Beam Envelopes; as I understand well, this module can be used to simulate a long waveguide (some mm or cm long) but without requiring a mesh size smaller than the signal wavelength. I have prepared a simple example of a waveguide that starts with a small width and ends with a bigger width (some kind of taper waveguide); the wave envelope change in this case should be minimal, so I'm expecting that a coarse mesh along the beam propagation direction is enough to describe the wave behaviour; unfortunately this is not the case, and I have to reduce the mesh size to a fraction of wavelength to see the results, as in the typical beam propagation methods.

Any suggestion? Thanks in advance

P.S. The file has the mesh and solutions stripped out in order to reduce the size of the file to the minimum.

Mesh Problem

December 6, 2013, 9:16 am

≫ Next: Meshing problem

≪ Previous: Large mesh with Beam Envelopes module

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Hello,

I have problem with mesh generation for my model. I made a 3D glass beads with lots of grains.
When I want to mesh that I faced some error in meshing. sometimes it meshed but then during study meshing makes a problem: (Failed to generate mesh for domains :...)
I spent lots of times to figure out the problem, but no success,
I would appreciate if any body could help me.
Thanks,
Saeed

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Meshing problem

December 12, 2013, 8:01 am

≫ Next: Optimisation of processing parameters in laser sintering of metal/alloy powders

≪ Previous: Mesh Problem

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Dear colleagues,

I'm modelling a thin walled element (solid geometry) and I want to mesh it with an hexahedral mesh with only one element along the thickness. I attached an image of the geometry.
The main problem is the complex geometry with circular holes and curves. I try to mesh a surface with quadrilateral element, but I can't do it on surfaces with holes.
Is it possible to mesh it with quadrilateral elements? If it is possible I can extrude them and obtain what I want.
If it is a problem I'll work with a triangular mesh.

I hope I was clear enough

Thanks for any suggestions
Best regards

Simone

Optimisation of processing parameters in laser sintering of metal/alloy powders

December 16, 2013, 12:30 am

≫ Next: Internal error in geometry processing.

≪ Previous: Meshing problem

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Hi everyone,
I am new to COMSOL Multiphysics..
Can anyone help me in simulating selective laser melting(SLM)/direct metal laser sintering(DMLS) of metal/alloy powder media in layer-by-layer fashion?
IN SLM process a high power laser beam falls on a thin layer(say 30 micron) of metal powder bed and scans according to CAD model given to the computer. This process is repeated till the CAD part is completed layer-by-layer fashion.

thank you in advance.

Internal error in geometry processing.

December 18, 2013, 1:47 pm

≫ Next: My biggest wish for X-mas: Solution for crack modeling

≪ Previous: Optimisation of processing parameters in laser sintering of metal/alloy powders

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Internal error code is 5018.

The error happened under the "Free Tetrahedral 1" category. Basically my model involves forced convection cooling on a flat plate, and the error pointed to the convective fluid domain. I suspect this is due to the interface of two materials or geometry.

My biggest wish for X-mas: Solution for crack modeling

December 19, 2013, 8:22 am

≫ Next: question about the mesh

≪ Previous: Internal error in geometry processing.

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Dear Comsol gurus, dear support,

my biggest wish for X-mas was, that the new 4.4 release would finally provide some reasonable approach for crack modeling as being standard in other software packages.

So why is there still no approach to include X-FEM or cohesive zone elements or equivalent?

Maybe there is a good reason for it due to the structure of the code or due to the lack of request?

I notice for four years now, that regardless of the person there is no reply to the questions regarding crack modeling. This does not help very much, so I would appreciate it, if anybody could come up with some rumors on future COMSOL plans :)

Wish you all the best,
Markus

question about the mesh

December 22, 2013, 4:14 pm

≫ Next: Meshing a twisted wire

≪ Previous: My biggest wish for X-mas: Solution for crack modeling

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in comsol i have made a 3D model:
There are two Geometries, a big sphere and a small cylinder in the sphere.
the mesh of the sphere can be made coarser, it's not important.
for the mesh of the cylinder, i want to make the edge of the bottoms of the cylinder feiner but in centre coarser.

i have tried to use the "boundary layer" to make the mesh for the cylinder. And then used the “Free Tetrahedral” to mesh the rest. but it doesn't work. only "Free Tetrahedral" is working and “boundary layer” hat no effect.

so how can i reach my goal? thank you for your help!