Better Late than Never

Frame finite elements abound in OpenSees, but something very useful has always been missing–a linear-elastic beam element with moment releases.

Sure, you can define two nodes at the release location and use the equalDOF command; however, that can be error prone and you’re at the mercy of the constraint handler. On the positive side, this approach will work for material nonlinear element formulations.

However, a good, old fashioned linear-elastic beam element with moment releases can get you pretty far in nonlinear structural analysis. With a small amount of logic, you can script an event-to-event analysis in order to determine the pushover curve and collapse mechanism for a frame.

Even G2 has such an element (element3). But not OpenSees, until pull request #270 modified the elasticBeamColumn element (2D version only) to take a moment release code as an optional input. The releases will also work with uniform distributed loads and point loads as member loads on the element.

Check the moment releases out, give them a try. They may even come in handy for this frame analysis challenge.

3 thoughts on “Better Late than Never

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.