Force Recorder Sign Convention

[mairead]

Hi,

I have a simply supported beam with a UDL along the full length so it has a sagging moment all along the beam. However when I use the globalForce Recorder for one of the elements along the beam I get My to have an opposite sign at either end of the element? I am confused as I would have thought they would have the same sign as there is a sagging moment at both locations, or are the moments at element ends always opposite in sign? If that is the case how can I tell whether the moment in the beam is hogging or sagging? My global axis is X along the beam, Y into the page and Z up.

Thanks very much.

M

[vesna]

Yes, for your case they should have opposite sign. The sign of the moment at the element end is not based on the moment diagram but is tied to the global coordinate system.