ABSTRACT
Figure 3-1 (top) Vertical compression (strain) in a medium transforms an imaginary circle into an ellipse with decreases in circumference and area.
(bottom) Now if a flexible ring is inserted in place of the imaginary ellipse and then is allowed to expand such that its circumference remains the same as the original imaginary circle, the medium in contact with the ring is compressed as shown by infinitesimal cubes at the spring lines, crown and invert.
