Figure 11 -- The motion of the core (not the flake platform) after the crack begins to propagate defines the static and dynamic modes. In the static mode, the core starts immediately towards its at-rest-position (to the left) when the crack begins. This is a result of the loading time being greater that the period of the core. In the dynamic mode, the core has a velocity in the same direction the flake platform is moving and, therefore, it continues in this direction when the crack begins. However, it immediately starts to slow down and ultimately reverses its direction towards the at-rest-position. This is a result of the loading time being less than or equal to the period.

The green arrows represent the direction of movement of the core at the time the crack begins. The red arrows are the direction of movement of the flake platform.