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Author Topic: Adding mass to a stiffened panel  (Read 1502 times)

eric

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Adding mass to a stiffened panel
« on: January 05, 2015, 02:11:54 PM »
I'm looking to determine isogrid dimensions from a frequency requirement using a Non-FEA project.  I need to account for the mass of a component that attaches to the panel when determining the frequency.  I tried to use "Added Weight", but there is no effect on the component structure when an analysis is completed with a non-trivial amount of additional mass.  Any insight?

Thanks!
Eric

James

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Re: Adding mass to a stiffened panel
« Reply #1 on: January 05, 2015, 02:23:12 PM »
The "Added Weight" does not feed into the panel frequency analysis. It probably should.

You can use the Bond Weight (units = lb/ft^2) on the Project Sizing Form > Options Tab > Constants which will increase the mass that is used in the panel frequency analysis.

-James

eric

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Re: Adding mass to a stiffened panel
« Reply #2 on: January 05, 2015, 02:34:45 PM »
Adding it as bond weight (any or all of three options) doesn't seem to impact the results either.

James

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Re: Adding mass to a stiffened panel
« Reply #3 on: January 05, 2015, 02:58:07 PM »
The local frequency will be unaffected but the panel frequency should account for the added bond weight. What panel concept is this?

eric

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Re: Adding mass to a stiffened panel
« Reply #4 on: January 05, 2015, 03:04:14 PM »
This is an isogrid concept.  I'm only looking at panel frequencies.

James

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Re: Adding mass to a stiffened panel
« Reply #5 on: January 05, 2015, 03:24:16 PM »
You're right. It's not working correctly for metallic isogrid. Two workaround that I can think of would be...
1. Scale the material density
2. Smear the extra weight into the skin by increasing the skin thickness

#2 seems easier..