March 25, 2021 at 8:27 pm
Mike Rife
Ansys Employee
Hi @vbb96vbb nYou have run into a classic issue with Finite Element models being too perfect. The flag is modeled as a perfectly flat surface with gravity acting in the plane of the surface. Our instincts are to expect the FEA result to show the flag droop, since that is our real-world experience. But in the real world the flag is not perfectly flat. There are really ripples in the fabric. nTo overcome this try a static-linear buckling-transient linked system approach like so:n
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nAnyway you will need to drag-and-drop the Engineering data and the Solution of the Buckling to the Transient Model cell manually. Set up the Static case as you already have: with the flag fixed on the left side, and apply gravity (-Y). When the solve is done change the buckling to find say 10 modes. Then pick one that kind of looks like a fluttering flag. If none suite your needs try solving for more modes. Note the scale factor on the results used so we can see the displacements. From the Mechanical Help -> Application Interface -> Ribbon -> Context Tabs; Result Context Tab we can see this image (scale factor here):n