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How to set the connection of the thread in a helix structure

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Hi All,

I need to set a model that is a helix structure for electromechanical simulations. There is no distance between each thread of the solenoid, which means each thread is connected at the tangent part. I don't want to make the thread slip when I apply the voltage potential. How to do that? How to make the thread connect one by one solidly?

Thank you sincerely.


11 Replies Last Post 2019年3月16日 GMT-4 下午2:28
Edgar J. Kaiser Certified Consultant

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Posted: 8 months ago 2019年3月14日 GMT-4 下午2:12

You might try the 'Rigid Connector' features.

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
You might try the 'Rigid Connector' features.

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Posted: 8 months ago 2019年3月14日 GMT-4 下午2:34

You might try the 'Rigid Connector' features.

Dear Edgar J.Kaiser,

Thank you for your help. But I didnot get the point. Can you tell me more details? How to set the Rigid Connector features?

Thank you sinerely.

>You might try the 'Rigid Connector' features. Dear Edgar J.Kaiser, Thank you for your help. But I didnot get the point. Can you tell me more details? How to set the Rigid Connector features? Thank you sinerely.

Edgar J. Kaiser Certified Consultant

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Posted: 8 months ago 2019年3月14日 GMT-4 下午3:34

You can apply rigid connector boundary conditions in 3D to boundaries, edges and points. As the name says they can rigidly tie parts of your model together, such as the connecting edges of your helix. I suggest you check the details of these features in the documentation. This will allow you to assess whether rigid connectors are what you need. And you can try them.

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
You can apply rigid connector boundary conditions in 3D to boundaries, edges and points. As the name says they can rigidly tie parts of your model together, such as the connecting edges of your helix. I suggest you check the details of these features in the documentation. This will allow you to assess whether rigid connectors are what you need. And you can try them.

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Posted: 8 months ago 2019年3月14日 GMT-4 下午4:16
Updated: 8 months ago 2019年3月15日 GMT-4 上午11:10

You can apply rigid connector boundary conditions in 3D to boundaries, edges and points. As the name says they can rigidly tie parts of your model together, such as the connecting edges of your helix. I suggest you check the details of these features in the documentation. This will allow you to assess whether rigid connectors are what you need. And you can try them.

Dear Edgar J.Kaiser,

Thank you for your help. But I only find the Rigid connector in boundaries . And I could not choose the edges that need to be connected. Furthermore, for the Helix structure, the contours do not always follow the tangent line of the threads. Can you show me an example for solving this problem? Here is an image for the problem that I mentioned above. https://www.dropbox.com/s/lz353iqkfsbj2ci/rigid%20connector.png?dl=0

Thank you sinerely.

>You can apply rigid connector boundary conditions in 3D to boundaries, edges and points. As the name says they can rigidly tie parts of your model together, such as the connecting edges of your helix. >I suggest you check the details of these features in the documentation. This will allow you to assess whether rigid connectors are what you need. And you can try them. Dear Edgar J.Kaiser, Thank you for your help. But I only find the Rigid connector in boundaries . And I could not choose the edges that need to be connected. Furthermore, for the Helix structure, the contours do not always follow the tangent line of the threads. Can you show me an example for solving this problem? Here is an image for the problem that I mentioned above. [https://www.dropbox.com/s/lz353iqkfsbj2ci/rigid%20connector.png?dl=0](https://www.dropbox.com/s/lz353iqkfsbj2ci/rigid%20connector.png?dl=0) Thank you sinerely.

Henrik Sönnerlind COMSOL Employee

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Posted: 8 months ago 2019年3月15日 GMT-4 上午2:53

Hi,

Rigid Connector on edges and points were introduced in version 5.4. So if you are running an older version you will only see the boundary selection.

As to the original question, I think you need to explain more in detail (maybe with a sketch) which deformations that you allow and not. To me, it seems more like a contact problem.

Regards, Henrik

Hi, Rigid Connector on edges and points were introduced in version 5.4. So if you are running an older version you will only see the boundary selection. As to the original question, I think you need to explain more in detail (maybe with a sketch) which deformations that you allow and not. To me, it seems more like a contact problem. Regards, Henrik

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Posted: 8 months ago 2019年3月15日 GMT-4 上午11:08
Updated: 8 months ago 2019年3月15日 GMT-4 上午11:12

Hi,

Rigid Connector on edges and points were introduced in version 5.4. So if you are running an older version you will only see the boundary selection.

As to the original question, I think you need to explain more in detail (maybe with a sketch) which deformations that you allow and not. To me, it seems more like a contact problem.

Regards, Henrik

Dear Henrik,

Thank you for your help. you could see from the image. the relative displacement of the threads are not accpected. There is not any gap between every two threads. The thread 1 and thread 2 should adhesive each other totally. (also for other threads.) I should not see the part 3 after the simulation.( the elongation part). I think it is a contact problem. But I don't know how to adhesive the threads together. And I do not have version 5.4 for Comsol.

https://www.dropbox.com/s/wp1amw076z7f12h/sketch.png?dl=0

Thank you sincerely.

Best regards,

Jie Mao

>Hi, > >Rigid Connector on edges and points were introduced in version 5.4. So if you are running an older version you will only see the boundary selection. > >As to the original question, I think you need to explain more in detail (maybe with a sketch) which deformations that you allow and not. To me, it seems more like a contact problem. > >Regards, >Henrik Dear Henrik, Thank you for your help. you could see from the image. the relative displacement of the threads are not accpected. There is not any gap between every two threads. The thread 1 and thread 2 should adhesive each other totally. (also for other threads.) I should not see the part 3 after the simulation.( the elongation part). I think it is a contact problem. But I don't know how to adhesive the threads together. And I do not have version 5.4 for Comsol. [https://www.dropbox.com/s/wp1amw076z7f12h/sketch.png?dl=0](https://www.dropbox.com/s/wp1amw076z7f12h/sketch.png?dl=0) Thank you sincerely. Best regards, Jie Mao

Edgar J. Kaiser Certified Consultant

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Posted: 8 months ago 2019年3月15日 GMT-4 下午3:08

You may also consider to design the helix with a small overlap of the windings. This would tie the windings together as well. The allowed degree of approximation depends on your primary question to the model.

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
You may also consider to design the helix with a small overlap of the windings. This would tie the windings together as well. The allowed degree of approximation depends on your primary question to the model.

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Posted: 8 months ago 2019年3月15日 GMT-4 下午3:15

You may also consider to design the helix with a small overlap of the windings. This would tie the windings together as well. The allowed degree of approximation depends on your primary question to the model.

Dear Edgar J. Kaiser,

I tried this method already. It did not work. The software still think they are not bonded together although I overlaped the threads.

Best regards,

Jie Mao

>You may also consider to design the helix with a small overlap of the windings. This would tie the windings together as well. >The allowed degree of approximation depends on your primary question to the model. Dear Edgar J. Kaiser, I tried this method already. It did not work. The software still think they are not bonded together although I overlaped the threads. Best regards, Jie Mao

Edgar J. Kaiser Certified Consultant

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Posted: 8 months ago 2019年3月16日 GMT-4 上午5:08

Jie Mao,

I was surprised that the overlap doesn't work. Obviously Comsol doesn't want to connect boundaries of objects overlapping themselves. Also the meshing seems to be tedious.

I got curious and tried something different. I introduce a second smaller helix running between the threads of the first one. It acts as something like a soldering bond. You may want to modify that to your needs. I attach an example in Comsol 5.3. Just execute the geometry tree step by step to learn how it works. Solve the model and you see that you have a union between the helix threads and the 'solder'.

The procedure may look cumbersome but is probably more physical than something like a rigid edge connector.

Good luck Edgar

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Jie Mao, I was surprised that the overlap doesn't work. Obviously Comsol doesn't want to connect boundaries of objects overlapping themselves. Also the meshing seems to be tedious. I got curious and tried something different. I introduce a second smaller helix running between the threads of the first one. It acts as something like a soldering bond. You may want to modify that to your needs. I attach an example in Comsol 5.3. Just execute the geometry tree step by step to learn how it works. Solve the model and you see that you have a union between the helix threads and the 'solder'. The procedure may look cumbersome but is probably more physical than something like a rigid edge connector. Good luck Edgar


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Posted: 8 months ago 2019年3月16日 GMT-4 上午11:48

Jie Mao,

I was surprised that the overlap doesn't work. Obviously Comsol doesn't want to connect boundaries of objects overlapping themselves. Also the meshing seems to be tedious.

I got curious and tried something different. I introduce a second smaller helix running between the threads of the first one. It acts as something like a soldering bond. You may want to modify that to your needs. I attach an example in Comsol 5.3. Just execute the geometry tree step by step to learn how it works. Solve the model and you see that you have a union between the helix threads and the 'solder'.

The procedure may look cumbersome but is probably more physical than something like a rigid edge connector.

Good luck Edgar

Dear Edgar,

Thank you very much.

I also tried this method. But it was hard to mesh. Here a are lots of warnings also in your program, which makes it hard to do the simulation.

Tips: In your model, the number of turns of Helix 2 could be number of turns of Helix 1 substract one, so that you do not need to delete entities.

In my system, I want to do a electromechanical simulation. The image is the side view of the model. It is a core-shell-shell structure. The high voltage potential is applied on the edges of the core. And use fixed constraint for one end of the Helix. Could you please try to do a simulation of this structure? I find mesh is very difficult for this structure. I use swept for mesh if there isn't an additional helix for soldering. However, if we add the additional helix, it shows me a lot of errors. So, how to solve this problem?

Thank you sincerely,

Best,

Jie Mao

>Jie Mao, > >I was surprised that the overlap doesn't work. Obviously Comsol doesn't want to connect boundaries of objects overlapping themselves. Also the meshing seems to be tedious. > >I got curious and tried something different. I introduce a second smaller helix running between the threads of the first one. It acts as something like a soldering bond. You may want to modify that to your needs. I attach an example in Comsol 5.3. Just execute the geometry tree step by step to learn how it works. Solve the model and you see that you have a union between the helix threads and the 'solder'. > >The procedure may look cumbersome but is probably more physical than something like a rigid edge connector. > >Good luck >Edgar Dear Edgar, Thank you very much. I also tried this method. But it was hard to mesh. Here a are lots of warnings also in your program, which makes it hard to do the simulation. Tips: In your model, the number of turns of Helix 2 could be number of turns of Helix 1 substract one, so that you do not need to delete entities. In my system, I want to do a electromechanical simulation. The image is the side view of the model. It is a core-shell-shell structure. The high voltage potential is applied on the edges of the core. And use fixed constraint for one end of the Helix. Could you please try to do a simulation of this structure? I find mesh is very difficult for this structure. I use swept for mesh if there isn't an additional helix for soldering. However, if we add the additional helix, it shows me a lot of errors. So, how to solve this problem? Thank you sincerely, Best, Jie Mao


Edgar J. Kaiser Certified Consultant

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Posted: 8 months ago 2019年3月16日 GMT-4 下午2:28

Yes you need to set up a user controlled mesh for that. But I think this can be done. It was meant to be a hint. I won't be able to afford more time for the detail work on this.

Good luck Edgar

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Yes you need to set up a user controlled mesh for that. But I think this can be done. It was meant to be a hint. I won't be able to afford more time for the detail work on this. Good luck Edgar

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