How to modify the block geometry, for example, by transforming the square face into round face?
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GEOMETRY
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Cap Faces of complex geometry
Hello everyone!
I´m sorry to bother you guys, but I simply can`t figure out how to solve two problems in COMSOL (4.4) and hope anyone could help.
I was given a ~20 MB step. geometry consisting 3 solids. The CAD-Software used is unknown to me. After havin imported it to COMSOL I get these 3 solids with waaaaaay too many edges, and therefore faces - e.g. attached picture .
My goal is to simulate the flow in the void of these 3 solids.
To do so, I first want to use the function "cap faces", convert the void into a solid, and delete the 3 imported ones....
The problem: for some reason it`s not possible to simply use "cap faces" while selecting the outer edges of a geometry like in the attached picture. The hole you see in the picture is actually a quite easy one compared to other geometry I`ve got in the model.
Also, after having used the function "form composite faces" first, and then using "cap faces", ALL the edges come back which where composited before.
Does anyone have an idea how to accomplish this goal of mine?
BTW: simple holes are being capped without any problem.
Thanks in advance
Eugen
I´m sorry to bother you guys, but I simply can`t figure out how to solve two problems in COMSOL (4.4) and hope anyone could help.
I was given a ~20 MB step. geometry consisting 3 solids. The CAD-Software used is unknown to me. After havin imported it to COMSOL I get these 3 solids with waaaaaay too many edges, and therefore faces - e.g. attached picture .
My goal is to simulate the flow in the void of these 3 solids.
To do so, I first want to use the function "cap faces", convert the void into a solid, and delete the 3 imported ones....
The problem: for some reason it`s not possible to simply use "cap faces" while selecting the outer edges of a geometry like in the attached picture. The hole you see in the picture is actually a quite easy one compared to other geometry I`ve got in the model.
Also, after having used the function "form composite faces" first, and then using "cap faces", ALL the edges come back which where composited before.
Does anyone have an idea how to accomplish this goal of mine?
BTW: simple holes are being capped without any problem.
Thanks in advance
Eugen
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photothermal or laser heating simulation in Comsol
Hi, I am new to Comsol. I am trying to simulate the temperature rising of the plasmonic structure during the laser illumination. Assuming the Electromagnetic wave plus the heat transfer will do the job. According to the suggestion from the Comsol support, one heat source was added using the total power loss of the electromagnetic wave. However, it doesn't work.
I have attached the model below. Apprecieate suggestions.
I have attached the model below. Apprecieate suggestions.
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ERROR: Complex number encountered in real expression(when calculate the DEP force)
Hello everyone:
I use Particle tracing module for fluid to calculate the DEP force exerted on the nano-sized particles.
When calculate the DEP I encountered a problem as follows:
Complex number encountered in real expression.
- Expression: (mod1.fpt.Ftz-d(mod1.qz,t)*d(mod1.fpt.mp,t))/mod1.fpt.mp
- Geometry: Particles
Anyone can help me ?
Thanks!
I use Particle tracing module for fluid to calculate the DEP force exerted on the nano-sized particles.
When calculate the DEP I encountered a problem as follows:
Complex number encountered in real expression.
- Expression: (mod1.fpt.Ftz-d(mod1.qz,t)*d(mod1.fpt.mp,t))/mod1.fpt.mp
- Geometry: Particles
Anyone can help me ?
Thanks!
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Oscillating the boundary wall in sine waveform
Hello,
I am trying to simulate laminar fluid flow in sawtooth profile boundary,
My questions are,
How to oscillate the boundary in sine wave form in time dependent??
The moving wall velocity formula is Amplitude*sine(2*pi*f*t)?? is the above formula is right to oscillate the wall in sine wave form??
I am trying to simulate laminar fluid flow in sawtooth profile boundary,
My questions are,
How to oscillate the boundary in sine wave form in time dependent??
The moving wall velocity formula is Amplitude*sine(2*pi*f*t)?? is the above formula is right to oscillate the wall in sine wave form??
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Load distribution
Hi guy, currently I doing the load distribution on the piezoelectric material.
May I know can I use the 3D model result -> 3D Plot group -> Surface ->Piezoelectric device (solid Mechanics) -> Stress -> von Mises stress function to determine the load distribution of applied compression force to the piezoelectric device?
If no, can I get any suggestion or guide for determining the applied load distribution on the piezoelectric device.
Thank you
May I know can I use the 3D model result -> 3D Plot group -> Surface ->Piezoelectric device (solid Mechanics) -> Stress -> von Mises stress function to determine the load distribution of applied compression force to the piezoelectric device?
If no, can I get any suggestion or guide for determining the applied load distribution on the piezoelectric device.
Thank you
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Moving mesh simulation
Hi
I am trying to do a simulation of railgun using comsol. Railgun is like an EM launcher setup where an object(armature) is accelerated between two parallel conductors by EM force. There is a tutorial available for this model in the model library of version 3.5 under AC/DC module. But the technique they have used in the tutorial is different from a moving mesh. They have not considered an actual moving armature but rather the conductivity of the volume representing the armature is changed for every time step. It made me wonder whether using moving mesh to simulate this model is possible in comsol? I specifically need to use the moving mesh module to actually move the armature and study the physics.
I am new to comsol. My question: Is it possible to do such type of moving mesh simulation using comsol?
Any help is much appreciated.
Thank you
I am trying to do a simulation of railgun using comsol. Railgun is like an EM launcher setup where an object(armature) is accelerated between two parallel conductors by EM force. There is a tutorial available for this model in the model library of version 3.5 under AC/DC module. But the technique they have used in the tutorial is different from a moving mesh. They have not considered an actual moving armature but rather the conductivity of the volume representing the armature is changed for every time step. It made me wonder whether using moving mesh to simulate this model is possible in comsol? I specifically need to use the moving mesh module to actually move the armature and study the physics.
I am new to comsol. My question: Is it possible to do such type of moving mesh simulation using comsol?
Any help is much appreciated.
Thank you
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How to get coefficient names?
Hi all,
I am new in COMSOL.
I set a "Coefficient Form PDE (c)" and I need the name of the absorption coefficient of the PDE, in order to use it in an expression.
I tried with "c.a11", but this variable is unknown.
How can I find the name of that parameter?
Is there a way to have a look to all the parameters used in my COMSOL project?
I am new in COMSOL.
I set a "Coefficient Form PDE (c)" and I need the name of the absorption coefficient of the PDE, in order to use it in an expression.
I tried with "c.a11", but this variable is unknown.
How can I find the name of that parameter?
Is there a way to have a look to all the parameters used in my COMSOL project?
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3D symmetry
Hello,
I am dealing with a 3D geometry in which I have a cone with a hexagonal base. I cut it into 6 axisymmetric equilateral triangles. I wish to give symmetry boundary conditions on the sides of the triangle. Can you guide me as to how to do this in the 3D case? I am attaching the workplane geometry, which I have extruded to form a cylinder.
Thanks,
Priyanka
I am dealing with a 3D geometry in which I have a cone with a hexagonal base. I cut it into 6 axisymmetric equilateral triangles. I wish to give symmetry boundary conditions on the sides of the triangle. Can you guide me as to how to do this in the 3D case? I am attaching the workplane geometry, which I have extruded to form a cylinder.
Thanks,
Priyanka
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Magnetic Insulation not applying correctly
Hi everyone,
I'm working on a figure-8 coil model that is widely used in medical treatment for neural diseases.
I have successfully modeled the kind of coil I wanted and created a boundary volume around it.
I'm interested in simulating its magnetic field intensity in both 2D planes and in 3D volume.
I have a problem that the magnetic insulation boundary conditions apply themselves to the coil itself - not to the boundary volume as planned, causing the results to appear only inside the conductors. For the boundary volume it tells that magnetic insulation is "not applicable".
I have attached a screenshot of the compiled result I got.
Would anyone have any ideas what could cause this.
Thank you for the help!
I'm working on a figure-8 coil model that is widely used in medical treatment for neural diseases.
I have successfully modeled the kind of coil I wanted and created a boundary volume around it.
I'm interested in simulating its magnetic field intensity in both 2D planes and in 3D volume.
I have a problem that the magnetic insulation boundary conditions apply themselves to the coil itself - not to the boundary volume as planned, causing the results to appear only inside the conductors. For the boundary volume it tells that magnetic insulation is "not applicable".
I have attached a screenshot of the compiled result I got.
Would anyone have any ideas what could cause this.
Thank you for the help!
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Diffusion and absorption simulation
Hello
I want to calculate the rate of absorption and diffusion of water from humid air into a solid material. However, I can only find information in COMSOL about diffusion spreading inside one material.
Can I model absorption and diffusion from a gas into a solid?
Thanks for any help
I want to calculate the rate of absorption and diffusion of water from humid air into a solid material. However, I can only find information in COMSOL about diffusion spreading inside one material.
Can I model absorption and diffusion from a gas into a solid?
Thanks for any help
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Mesh distribution and piezoelectric device antisymmetry Function
Hi guy,
May I know the function of mesh -> Free tetrahadral -> distribution? If I applied a compression force on an object surface, is it function to determine the distribution of the applied force?
I have no ideal of the antisymmetry function under piezoelectric device physic? May I know how to use the antisymmetry function?
Hope someone willing to help and answer my question, thank you~
May I know the function of mesh -> Free tetrahadral -> distribution? If I applied a compression force on an object surface, is it function to determine the distribution of the applied force?
I have no ideal of the antisymmetry function under piezoelectric device physic? May I know how to use the antisymmetry function?
Hope someone willing to help and answer my question, thank you~
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Analysis of stress in fluid structure interface module---
Hello
I have a doubt. I was working in Fluid structure interface module to analyze the drug delivery system. I have computed the flow analysis and I need to analyze the structure for its stress. But I dont know how to compute the stress analysis in fluid structure interface module. Can anyone help me how to analyze the stress.
Or else I dont know whether such analysis requires two module to compute. I tried by including the structural analysis with fluid structure interface but input varies for these two modules. Fluid structure interface involve input to be applied in terms of velocity and structural analysis requires input in pressure or force mode. But the conversion from velocity to pressure is not exactly known.
So please help in finding such solution
Thanks and regards
Dinesh Ram G
I have a doubt. I was working in Fluid structure interface module to analyze the drug delivery system. I have computed the flow analysis and I need to analyze the structure for its stress. But I dont know how to compute the stress analysis in fluid structure interface module. Can anyone help me how to analyze the stress.
Or else I dont know whether such analysis requires two module to compute. I tried by including the structural analysis with fluid structure interface but input varies for these two modules. Fluid structure interface involve input to be applied in terms of velocity and structural analysis requires input in pressure or force mode. But the conversion from velocity to pressure is not exactly known.
So please help in finding such solution
Thanks and regards
Dinesh Ram G
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MEMS - Micro bridge heating - Cant see temperature difference
Hi, i'm trying to simulate a micro bridge heated by laser. The bridge seems to be moving but when i when i'm viewing the temperature differences, all the bridge seems to be at the same temperature...
The colors show a temperature difference but the values shows the same temperature..
I dont think its a range thing..
The colors show a temperature difference but the values shows the same temperature..
I dont think its a range thing..
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add mechanical damping, not convergence
When I compute a piezoelectric transducer in a water domain, the solution works well and convergence. However, when I add mechanical damping to the piezoelectric material and keep others all the same, the solution can not convergence, I am wondering why?
have a good day.
--
sandra wang
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Silicon parameters
Hi..
I am working on silicon simulation in FDTD software. I have to build a waveguide for THz waves (0.1 - 1.2 THz) with silicon od carrier concentration = 10^18 cm^-3. What is the static permittivity of silicon and collision frequency of silicon at this concentration. Please help me.
I am working on silicon simulation in FDTD software. I have to build a waveguide for THz waves (0.1 - 1.2 THz) with silicon od carrier concentration = 10^18 cm^-3. What is the static permittivity of silicon and collision frequency of silicon at this concentration. Please help me.
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Compute study for only the 2D cross section of a 3D geometry?
Hi all,
I have made a 3D model in COMSOL vs 5.2a of a microfluidics channel and am attempting to model the DEP response of cells in the channel to the presence of an electric field created by electrodes on the channel floor. In an effort to to now cut down the computation time, I have made a 2D geometry component by following this example (briefly: I made a workplane in my 3D model then made a new component whose 2D geometry is defined as the cross section of the 3D geometry along that workplane. www.comsol.com/blogs/creating-...etries-in-comsol-multiphysics/). The 2D geometry looks great but my questions now are:
1. Is there a fast or automatic way to transfer all the physics from the 3D model to the 2D cross section or do I need to redefine all the physics modules for the 2D geometry? (for example: the inlet and outlet of fluid flow, the electric potential applied to various electrodes, the materials within the interior of the channel, etc).
2. How do I make a study that will compute the solution only for the 2D geometry and not the 3D geometry so I can achieve faster simulation times? When I add a study I don't see any way to specify the study to operate only one geometry. or is the answer to make a new program that only has the 2D model to begin with?
I am new to COMSOL so I may not be phrasing this question very clearly, but please let me know if you have any answers, suggestions, or could use some clarification.
Thanks so much for your help!!
Shari
I have made a 3D model in COMSOL vs 5.2a of a microfluidics channel and am attempting to model the DEP response of cells in the channel to the presence of an electric field created by electrodes on the channel floor. In an effort to to now cut down the computation time, I have made a 2D geometry component by following this example (briefly: I made a workplane in my 3D model then made a new component whose 2D geometry is defined as the cross section of the 3D geometry along that workplane. www.comsol.com/blogs/creating-...etries-in-comsol-multiphysics/). The 2D geometry looks great but my questions now are:
1. Is there a fast or automatic way to transfer all the physics from the 3D model to the 2D cross section or do I need to redefine all the physics modules for the 2D geometry? (for example: the inlet and outlet of fluid flow, the electric potential applied to various electrodes, the materials within the interior of the channel, etc).
2. How do I make a study that will compute the solution only for the 2D geometry and not the 3D geometry so I can achieve faster simulation times? When I add a study I don't see any way to specify the study to operate only one geometry. or is the answer to make a new program that only has the 2D model to begin with?
I am new to COMSOL so I may not be phrasing this question very clearly, but please let me know if you have any answers, suggestions, or could use some clarification.
Thanks so much for your help!!
Shari
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2D results as initial conditions to a 3D model
Hi,
I'm doing a simulation of moisture and heat distribution on a soil profile.
On the first step I've made a 2D simulation of my soil that is a rectangle.
Now I have a heat exchanger buried in my soil and therefore, I have a "z" axis to add to my model. Assuming that the changes in the soil occurs just on depth direction, I want to take the results of my 2D simulation and put as initial conditions to my extruded 3D soil domain.
I've searched here but didn't found how to do this. Any tip for me?
Another problem, the mesh won't be the same. How to solve this?
Thanks in advance.
I'm doing a simulation of moisture and heat distribution on a soil profile.
On the first step I've made a 2D simulation of my soil that is a rectangle.
Now I have a heat exchanger buried in my soil and therefore, I have a "z" axis to add to my model. Assuming that the changes in the soil occurs just on depth direction, I want to take the results of my 2D simulation and put as initial conditions to my extruded 3D soil domain.
I've searched here but didn't found how to do this. Any tip for me?
Another problem, the mesh won't be the same. How to solve this?
Thanks in advance.
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MEMS Stresses and Strains
Hello,
I am relatively new to COMSOL and am trying to model a simple deformation of a MEMS bilayer. My geometry consists of a polyimide support (micro-meter dimensions) and a gold layer on top. I am constraining the polyimide (zero movement in y direction) on one side surface and applying a force on the opposite side surface (in the minus y direction). I am also applying a Roller boundary conditon on the two surfaces which are not orthogonal to the force. Due to the small dimensions of my model, I am obliged to choose a "finer" mesh.
I get the eror "Failed to find a solution. Out of memory during LU factorization. Returned solution is not converged."
I would be greatful for any suggestions that could make my model converge.
Thank you very much,
Amanda
I am relatively new to COMSOL and am trying to model a simple deformation of a MEMS bilayer. My geometry consists of a polyimide support (micro-meter dimensions) and a gold layer on top. I am constraining the polyimide (zero movement in y direction) on one side surface and applying a force on the opposite side surface (in the minus y direction). I am also applying a Roller boundary conditon on the two surfaces which are not orthogonal to the force. Due to the small dimensions of my model, I am obliged to choose a "finer" mesh.
I get the eror "Failed to find a solution. Out of memory during LU factorization. Returned solution is not converged."
I would be greatful for any suggestions that could make my model converge.
Thank you very much,
Amanda
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Reusing a deformed geometry for a new study
My goal is to model a loading on a wire that has some slack. So, ideally, the wire should deform under some predefined displacement initial condition and then be subjected to a load.
I am trying to reuse the geometry from the initial displacement step so that the stresses associated with this displacement (which are not strictly correct because the original model did not account for slack) are not accounted for during the loading. I followed basic workflows from other forum posts, to export and import the first step's mesh, but it only yields the undeformed mesh.
Please advise.
I am trying to reuse the geometry from the initial displacement step so that the stresses associated with this displacement (which are not strictly correct because the original model did not account for slack) are not accounted for during the loading. I followed basic workflows from other forum posts, to export and import the first step's mesh, but it only yields the undeformed mesh.
Please advise.
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