Learning Forum

[Enrique Ortega]

Hi all, I am trying to solve an inflatable structure under wind loads in ansys workbench (2022R2) using fluent and transient mechanical solvers. The structure consists of a thin membrane with half-cylinder cross section shape (like a hangar). A constant internal pressure helps to maintain the shape and the fluid impacts the external surface. I found a paper on the web that said that in ansys workbench it is not possible to simultaneously apply a constant pressure (mechanical solver side) and fluid loads (fluent side) on a membrane shell because it does not differentiate between internal and external faces and in this case the fluid loads overwrites the constant pressure applied in mechanics to pressurize the structure. In the paper two different membrane shells (separated by a distance equal to the thickness of the original membrane) were used to simulate the inner and outer faces. Pressure was applied to the inner surface while the fluid-solid interface is the outer surface. These faces are connected in mechanical by using bound contact. Is there another way to circumvent this problem? Thanks in advance!

[RM]

Hi ,
Did you tried to do so in your model? If yes, does it throw any error? Could you please share that with me.

[Enrique Ortega]

Hello,

thanks for your reply. I haven't tried that solution yet because the structural model is complex (see a picture below) and I would like to know if there is another possibility to avoid modifying the geometry. Also, I did a test with a simple model and I'm not sure that two half-thickness membranes each joined by contact will behave like the original membrane. It is important for our model not only the displacement but also the stresses.

I would like to know if there is a possibility to apply fluid and pressure loads on both faces of the membrane, or a way to do it without resorting to the solution I mentioned in the document.

Thanks in advance!

Enrique Ortega

[RM]

Hi,

You'll need two bonded shells in WB whereas it is not needed in SyC GUI outside WB.

Use solid/solid shell elements in Mechanical. Then you can create FSI with each side with solid/solid shell and connect one to Fluent wall and and one to wall-shadow.