Adding mass to a stiffened panel

[eric]

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]

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]

Adding it as bond weight (any or all of three options) doesn't seem to impact the results either.

[James]

The local frequency will be unaffected but the panel frequency should account for the added bond weight. What panel concept is this?

[eric]

This is an isogrid concept.  I'm only looking at panel frequencies.

[James]

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..