Tapered Fiber Element with Warping Coming Soon

[MDSmith526]

I just thought I would update you guys. We have been working on a tapered displacement-based finite element for thin-shelled members for some time. We are deep in the verification phase. Our element is a beam-column element utilizing fiber sections. It has 14 degrees of freedom, the newest DOFs are for section warping. It is based on an element developed by Chang 2006 at Georgia Tech. We created a new type of fiber, fiber section, element, and 3 new geometric transformations which account for the 14 DOFs.

So far we have verified:
- the elastic linear stiffness for all DOFs
- Flexural buckling in strong and weak axis for I-shaped members
- All elastic LTB cases in Andrade 2007
- Plastic strong and weak axis moments
- Residual stresses are compatible

We are working on evaluating inelastic lateral beam buckling now. We have several cases we are testing from two Bradford papers. We did some test cases with post-buckling pushover and cyclic pushover and they look excellent. After the cyclic verifications we will compare with our 10 laboratory tests. Then we will check to ensure we have properly included the dynamic properties and try a time-history analysis.

Does anyone have any advice on what else we should verify prior to wrapping this up? We expect that the test-model correlation will be poor due to local buckling. After we verify this element we will proceed with modifying it for flange local buckling. We are open to any good ideas on how to incorporate that as well. We may modify the material or the fiber properties or add additional internal DOFs if we can.