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acoustic-structure interaction using form assembly

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Hi In my model, the structure domain is immersed in a air domain. Usaually we will use form union at the end of the geometry. But for some reason, I need to use form assembly at the end to modify the boundary condition of the structure domain.

Does anyone know how can I do the acoustic-structure interaction with form assembly?


1 Reply Last Post Apr 15, 2019, 11:19 a.m. EDT
Henrik Sönnerlind COMSOL Employee

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Posted: 6 years ago Apr 15, 2019, 11:19 a.m. EDT
Updated: 6 years ago Apr 15, 2019, 11:19 a.m. EDT

Hi,

There is no built-in such coupling. You can however set it up manually. What you need is

  1. A pressure load on the structural side
  2. A normal accceleration on the acoustics side
  3. Extrusion coupling operators moving the variables from one side to another.

In order to see how to set up the loads, you can take a look at

https://www.comsol.com/model/vibrations-of-a-disk-backed-by-an-air-filled-cylinder-188

One of the variants there uses a manual coupling, so you can see which nodes to use. However, you cannot just pick up the variables as in the example, since they live on different boundaries. You have to type them in yourself, using expressions like genext1(acpr.pt). Look in Equation View for the Acoustic-Structure Boundary multiphysics coupling to find the names of the appropriate variables.

Regards,
Henrik

-------------------
Henrik Sönnerlind
COMSOL
Hi, There is no built-in such coupling. You can however set it up manually. What you need is 1. A pressure load on the structural side 2. A normal accceleration on the acoustics side 3. Extrusion coupling operators moving the variables from one side to another. In order to see how to set up the loads, you can take a look at One of the variants there uses a manual coupling, so you can see which nodes to use. However, you cannot just pick up the variables as in the example, since they live on different boundaries. You have to type them in yourself, using expressions like *genext1(acpr.pt)*. Look in **Equation View** for the **Acoustic-Structure Boundary** multiphysics coupling to find the names of the appropriate variables. Regards, Henrik

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