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Old   August 4, 2011, 01:16
Default earthquake spectrum
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Hamed
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Hi all,

I want to model a tank sloshing with respect to earthquake acceleration. How should I define the earthquake spectrum for ansys cfx? I'm doing mesh motion.

Regards;
hamed
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Old   August 4, 2011, 18:40
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CFX cannot model in the frequency domain like modal analysis in FEA. You are going to have to convert it into a displacement versus time and impose that as a mesh motion.
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Old   August 6, 2011, 09:32
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Thanks for the reply.
If I have a graph of displacment vs time, how should input that to cfx as the mesh displacement?

best regards;
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Old   August 7, 2011, 08:37
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Have a look at the tutorial examples for how to implement moving mesh.
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Old   August 7, 2011, 09:48
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Thanks. I know how to do mesh motion with a known equation. But know I have the graph of acceleration vs time. If I manage to integrate it and get the plot of displacement vs time, how can I give this as mesh motion. It is not an equation which I could simply enter for mesh motion displacement.

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Old   August 7, 2011, 18:53
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If you have the equation of motion then why can't you use it?
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Old   August 7, 2011, 20:11
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No I don't have the equation. As I said I just have a graph of displacment vs time. I don't know how to implement this graph to mesh motion.
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Old   August 8, 2011, 04:24
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Ali Torbaty
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Quote:
Originally Posted by enghamed View Post
No I don't have the equation. As I said I just have a graph of displacment vs time. I don't know how to implement this graph to mesh motion.

Create a text file from your data with X Y format, then import it into a CFX function.
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Old   August 8, 2011, 08:08
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Dear Ali,
Can you please be more specific and guide me on this.
How should I make the text file and then how can I input it in cfx?

Thank you very much.
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Old   August 8, 2011, 18:26
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Use a 1D interpolation function. I set these up by generating the function with some dummy data then editting it in the command editor to include your data points.
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