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Solver Error with Parallel Plate Capacitor
Posted Jun 10, 2010, 1:37 p.m. EDT 1 Reply
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I'm attempting to get familiar with COMSOL 4.0, despite the dearth of tutorials or explanations. I wanted to make a simple 2-D parallel plate capacitor model. So, i made two rectangles (to represent the plates) and a large rectangle to encompass them (to represent air. I then set the boundaries of the plates to be electric potentials with a +V and a -V and I set my left most boundary as a ground. I mesh it then right click "study 1" and click compute, but it gives me this error:
Failed to evaluate expression.
- Expression: d(((-mod1.es.Dx*test(mod1.Vx)-mod1.es.Dy*test(mod1.Vy))*mod1.es.d)*(dvol),{test@1})
Failed to evaluate variable.
- Variable: mod1.es.Dy
- Defined as: (((mod1.es.epsilonryz*mod1.es.Ez)+((mod1.es.Ey*mod1.es.epsilonryy)+(mod1.es.epsilonryx*mod1.es.Ex)))*epsilon0 const)
Failed to evaluate variable.
- Variable: mod1.es.epsilonryz
- Defined as: mat.epsilonr23
Failed to evaluate variable.
- Variable: mat.epsilonr23
- Geometry: 1
- Domain: 1 2 3
Any suggestion on how to remedy this? Are there any COMSOL 4.0 examples/tutorials (not 3.5 examples!).
Failed to evaluate expression.
- Expression: d(((-mod1.es.Dx*test(mod1.Vx)-mod1.es.Dy*test(mod1.Vy))*mod1.es.d)*(dvol),{test@1})
Failed to evaluate variable.
- Variable: mod1.es.Dy
- Defined as: (((mod1.es.epsilonryz*mod1.es.Ez)+((mod1.es.Ey*mod1.es.epsilonryy)+(mod1.es.epsilonryx*mod1.es.Ex)))*epsilon0 const)
Failed to evaluate variable.
- Variable: mod1.es.epsilonryz
- Defined as: mat.epsilonr23
Failed to evaluate variable.
- Variable: mat.epsilonr23
- Geometry: 1
- Domain: 1 2 3
Any suggestion on how to remedy this? Are there any COMSOL 4.0 examples/tutorials (not 3.5 examples!).
1 Reply Last Post Jun 10, 2010, 2:24 p.m. EDT
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Posted:
1 decade ago
Not sure how I fixed it, but I redrew and built it and the error stopped happening.
However, I still have a question of interest. I'm trying to model the capacitive coupling between two wires attached to something like a circuit board. Simply, I built a large rectangle which represents the circuit board, and three small rectangles that represent the wires. I extruded these so that they are 3-dimensional. However, i'm kind of confused about which physics package to choose. I want to send a current down these wires and figure out if there is a capacitive coupling occurring between them. I'm not sure which settings to choose. The circuit board itself I thought should be an electric insulator, but I don't see that option.
Can anyone give some suggestions on how I might be able to model this?
However, I still have a question of interest. I'm trying to model the capacitive coupling between two wires attached to something like a circuit board. Simply, I built a large rectangle which represents the circuit board, and three small rectangles that represent the wires. I extruded these so that they are 3-dimensional. However, i'm kind of confused about which physics package to choose. I want to send a current down these wires and figure out if there is a capacitive coupling occurring between them. I'm not sure which settings to choose. The circuit board itself I thought should be an electric insulator, but I don't see that option.
Can anyone give some suggestions on how I might be able to model this?