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Max Number of Allowed Load Combinations?

Max Number of Allowed Load Combinations?

Max Number of Allowed Load Combinations?

(OP)
We're analyzing a structure with robotic loads on it that can occur at different instances in time. We potentially want to evaluate 65,000 LC's in a solve. Does Risa allow this?

I see in the literature that up to 1000 BLC's are allowed but I haven't found anything on LC's.

RE: Max Number of Allowed Load Combinations?

That sounds interesting. 65k load combos is quite a few. Perhaps some of the cases could be better expressed as dynamic loads?

RE: Max Number of Allowed Load Combinations?

Without knowing the layout of these robotic loads, trying to treat them as a moving load (instead of nodal or member loads) could help with reducing the # of LC's.

Please note that is a "v" (as in Violin) not a "y".

RE: Max Number of Allowed Load Combinations?

(OP)
Thanks for the suggestions. The robots aren't moving along the structure but their base is fixed in place and they apply forces and moments to the structure at a single point.

RE: Max Number of Allowed Load Combinations?

A few thoughts are to attempt to find the extreme forces in each restrained DOF and then apply them simultaneously as static loads. The other option would be to make some dynamic load functions that represent the reaction for each restrained DOF then run them as dynamic loads. Risa allows you to have variable forcing functions over time.

RE: Max Number of Allowed Load Combinations?

The Before You Begin section of the RISA help file should have information on program limitations. I just pulled up the on-line version and it suggested that the LC's are limited to 5000.

https://risa.com/risahelp/risa3d/index.htm#Common_...

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