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, 3138.

Strain
Machine
A Macromedia Director 8.5 Application for Introducing
the Concepts of Simple and Pure Shear


Figure 8.
Vectordisplacement 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 pieshaped segment bisected by Z has been shortened
while those with orientations lying within the pieshaped 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 xcoordinate axis, i.e., the direction of shear.
As with figure 9 any material line whose orientation lies with the
pieshaped segment bisected by Z has been shortened while those
with orientations lying within the pieshaped segment bisected by
X have been lengthened. 

