Physical model of uniaxial extension or shortening of a 2D layer

This model was designed by Vince Cronin. The initial idea was to create a model that featured a reasonably homogenous uniaxial shortening or stretching. Other design goals eventually developed, once the basic design had proven to be educationally useful and successful. In particular, the design has evolved in the direction of providing a model that is inexpensive to build, involves materials that are commonly available, is easy to use, and can be stored without taking-up much space.

Lisbeth "Nicky" Arellano asked Dr. Cronin to participate in an Honors project during the fall semester of 2013. They decided to work on refining the uniaxial stretch/shorten model, which at that time involved a base that was sturdy but was bulky, a little bit expensive and required carpentry equipment and skills.

Dr. Cronin was asked to help with a UNAVCO short course, presented mostly to teachers who work in the middle-school to 2-year college range, and he developed a very simple version of the model using foamboard, rulers and binder clips. That experience helped in the development of the current version of the model.

In the summer of 2014, Ms. Arellano and Dr. Cronin submitted an abstract for the annual meeting of the Geological Society of America, which was to be held in late October in Vancouver, British Columbia, Canada. The organizers of the session to which the abstract had been submitted asked that the presentation include both a paper poster and some sort of computer or video production that could be displayed on a large-screen monitor. A video was produced, which is accessible in several different resolutions. The video provides instructions on how to make the model, as well as some examples of deformation experiments.

The materials used in the current model include the following:

• a piece of 1/8" thick melamine board. Melamine is the white finish on dry-erase whiteboards. If this is not available, you can use a 1/8" piece of masonite with one smooth side, or a 1/4" thick piece of foamboard. Whichever you use, cut the board to a size of 10" x 14".
• an 8.5" x 20" piece of swimsuit liner material, which is an elastic fabric that stretches approximately the same in all directions. This is available from almost any fabric store.
• a 10" x 1.25" x ~1/8" piece of rubber or rubberized plastic foam, of the sort that tool-drqwer liners are made of. This is available in rolls or sheets anywhere tool boxes or tool cabinets are sold, such as home-improvement stores or Sears.
• a 10" x 1.25" x ~1/8" piece of masonite. (An inexpensive wooden ruler will also work for this part.)
• an inexpensive wooden ruler, 1 foot long.
• 8 medium-sized binder clips, available from an office-supply store or WalMart
• 2 small-sized binder clips

Reference

Arellano, L., and Cronin, V.S., 2014, A physical model of near-homogeneous 1-D horizontal shortening or stretching of a ~2-D layer: Geological Society of America, Abstracts with Programs, v. 46, no. 6, p. 501; accessible online via https://gsa.confex.com/gsa/2014AM/webprogram/Paper248483.html

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All of the original content of this website is © 2014 by Vincent S. Cronin