Girty, G. 2002. Strain Machine, A Macromedia Director 8.5 Application for Introducing the Concepts of Simple and Pure Shear. In: Bobyarchick, A. 2002. Visualisation, Teaching and Learning in Structural Geology. Journal of the Virtual Explorer, 9, 31-38.
Strain Machine
A Macromedia Director 8.5 Application for Introducing
the Concepts of Simple and Pure Shear

Figure 8. Vector-displacement maps based on 7 strain increments with (e+1) = 1.1 and γ = 0.3. (A) Pure shear. (B) Simple shear. Click on the Show Initial Circle and Strain Ellipse button to gain access to animations of particle displacement paths.  Note the different paths that particles travel as they are displaced from their positions on the circumference of the circle to their positions on the strain ellipse.

Figure 9.  To observe the positions of lines of no finite longitudinal strain during seven increments of pure shear slide the silver ring to the right or click on the Play Movie button. Note that during the experiment that the X and Z principal strain axes lengthened and shortened, but otherwise remained stationary. Any material line whose orientation lies with the pie-shaped segment bisected by Z has been shortened while those with orientations lying within the pie-shaped segment bisected by X have been lengthened.

Figure 10. To observe the positions of lines of no finite longitudinal strain during  seven increments of simple shear slide the silver ring to the right or click on the Play Movie button. Note that the X and Z principal strain axes have rotated toward the direction of shear while one line of no finite longitudinal strain lies unchanged and parallel to the x-coordinate axis, i.e., the direction of shear. As with figure 9 any material line whose orientation lies with the pie-shaped segment bisected by Z has been shortened while those with orientations lying within the pie-shaped segment bisected by X have been lengthened.

 

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