Steel Educators' Tip Sheet

October 2004

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Overhead Transparency Film + Packing Tape = Beam Buckling Models

Teaching aids can sometimes be found in the most unexpected of places – or materials. Dr. Scott Civjan demonstrates beam buckling modes using a simple combination of overhead transparency plastic and packing tape. Dr. Civjan, an Associate Professor in the Department of Civil and Environmental Engineering at the University of Massachusetts at Amherst, says he first tried paper without success. He also had large foam models that worked well, but students were reluctant to try bending these models after class. Also, the large models were difficult to transport.

Says Dr. Civjan, “after searching the Internet for some sort of available model to no avail, I taped these up - quickly realizing that I could make 4 to 6 of each type, put students in small groups of 3 or 4, and have them tell me what initiates the failure and why that happens based on the dimensions.” It is sometimes difficult to distinguish the initiating failure from the final state, especially in the web-buckling model. However, this leads into a brief discussion about checking the capacity associated with each mode of failure separately and taking the lowest value.

Dr. Civjan purchased a roll of overhead transparency film four years ago and is still using the same roll to make his models. “It takes a day during the summer to make a few sets to pass out in class; then half of them get mangled by the class and can be remade the next summer.” A darker shade of packing tape is recommended – the buckled components catch the light and reveal the buckled shapes more clearly. “The two down sides of this are that, since the tape is heavier than the clear tape I originally used, the web buckling does not show up as clearly, and the models ‘crease’ more easily when students push them too far,” says Dr. Civjan.

For more information on how to make some beam buckling models of your own, go to the AISC WET Forum, click on ‘AISC WET Files’, and select “BeamBuckling_Civjan.PDF".

Beam Buckling Models and a Close-up View of Flange Local Buckling

	Tip of the Month Here's an example of a teaching aid for flexural members:
	ANIMATION: Beam Buckling
	WHERE CAN I FIND THIS? AISC WET CD à Visual Aids à Animations à Buckling à Beam Buckling
	DESCRIPTION: Shows the different beam buckling modes, and what causes that buckling.
	Want more tips? Click here [+]

This Month's Photo

Check out the "Photo of the Month." "Steelframe.JPG" is a photo of a Purdue University campus building under construction. This photo can be used to illustrate beams and girders as well as methods for providing lateral support. For this photo, go to the AISC WET Forum and click on 'AISC WET Photos'.

This Month's Poll

Tell us your main sources for teaching aids (i.e., textbooks, colleagues, AISCWET CD, etc.). Log on to the AISCWET Yahoo! Group and click on 'Polls'.

This newsletter was created by Seung Kun Oh, a Civil Engineering student at Purdue University.