Dr. Kim Roddis, Professor and Chair of the Civil & Environmental Engineering department at The George Washington University, took some time out to comment on her favorite teaching aids, the
Steel Educators' Tip Sheet, and materials currently available through the
Tools and Tips for Steel Educators website and the
AISC WET Forum.
Dr. Roddis comments that one way in which she has found the Steel Educators' Tip Sheet helpful is that it gives her the chance to see how other instructors are teaching buckling limit states. "Dr. Civjan's beam buckling models are a great physical tool he's added to our shared kit (October 2004 Tip Sheet and featured Tip on Teaching Aids, below). Dr. Liu posted a file about using paper to demonstrate local column buckling," says Roddis. Meanwhile, one of Dr. Roddis' favorite parts of the AISC WET CD for class use is the series of animations on buckling. She also feels that the compression member slides provided by Dr. Aktan (September 2004 Tip Sheet) complement the AISC WET column buckling animation very well.
Dr. Roddis also has her own local buckling demonstration. "When I do my lecture on local buckling," says Roddis, "I
bring two soda cans to class, one empty and one unopened. I ask the
class to review the limit states we've covered for columns, which at
that point in the course are the compressive yield and global buckling
states. I stand on the unopened soda can successfully, then on the
empty soda can with the expected local buckling failure (sometimes
requiring a bit of deliberate off-axis loading)."
Dr. Roddis then passes the cans around
and asks for discussion about the failure mode and why the unopened can
does not buckle. Often a student suggests that the can does not buckle
because it is "full", so she will pursue the thought experiment of what
would happen if she opened the can and stood on it with the soda still
there. "I don't actually do this demo," says Roddis, but she suggests that the students try it at home in
the bathtub. That clarifies that the can needs to be "full" of gas, or
pressurized, to prevent the local buckling. "The students definitely appreciate the undignified demonstation."
To download teaching aids mentioned by Dr. Roddis, go to the AISC WET Forum and click on ‘AISC WET Files’.
