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Solution isn't converging

Posted 5 apr 2013, 10:34 GMT-4 RF & Microwave Engineering Version 4.2a 4 Replies

Gustavo Leite Silvano
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Hello everyone,

I'm having a problem with my simulation, where it isn't converging. It's a very thin plate (10 nm) of graphene, and the dimensions of it are around 0,5 um. I've made a simulation where the dimensions of the plate where about 10 um, and it converged correctly, but when I reduced it to 0,5 um, it isn't converging. There's another simulation where I choosed a 1 um dimensio, but I had to incresce the height of the plate to 50 nm. What I have to do to have a covergion.

The error mensage is "Failed to find a solution for the initial parameter.
Multigrid canceled.
Returned solution is not converged."

Thanks
4 Replies Last Post 8 apr 2013, 22:03 GMT-4
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 5 apr 2013, 15:07 GMT-4
Hi

have you thought of replacing the layer by a "thin physics" BC, as thin bulk layers need still a few mesh elemenets across and then the overall msh becomes very small and dense

--
Good luck
Ivar
Hi have you thought of replacing the layer by a "thin physics" BC, as thin bulk layers need still a few mesh elemenets across and then the overall msh becomes very small and dense -- Good luck Ivar
Gustavo Leite Silvano
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Posted: 1 decade ago 6 apr 2013, 18:00 GMT-4
Hello Ivan,

You are telling me that I have to add a boundary condition in my structure? I already use the "Wave Equation" on it, because the material is anisotropic. I tried to use the impedance boundary condition but it only accept the external layer of the simulation.

Can you explain more what I have to do?

Thanks for your time
Hello Ivan, You are telling me that I have to add a boundary condition in my structure? I already use the "Wave Equation" on it, because the material is anisotropic. I tried to use the impedance boundary condition but it only accept the external layer of the simulation. Can you explain more what I have to do? Thanks for your time
Muthuraman Chinnadurai
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Posted: 1 decade ago 6 apr 2013, 23:45 GMT-4
I think the problem lies in meshing.
I think the problem lies in meshing.
Gustavo Leite Silvano
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Posted: 1 decade ago 8 apr 2013, 22:03 GMT-4
Hello!

The mesh that i'm using is the most fine that I could get if my hardware. In fact, I'm simulating if a mesh of something around 400.000 elements. The problem can be the way that I defined my mesh? Because I just selected the domain and chosed the configuration of the mesh, I didn't made a more precise choose of the mesh in each reagion.

Thanks for your time
Hello! The mesh that i'm using is the most fine that I could get if my hardware. In fact, I'm simulating if a mesh of something around 400.000 elements. The problem can be the way that I defined my mesh? Because I just selected the domain and chosed the configuration of the mesh, I didn't made a more precise choose of the mesh in each reagion. Thanks for your time

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