Figure 15 -- A biface under static loading conditions. The red represents the loading time of 0.0002 seconds. The blue is one cycle of free response (0.0001950 seconds) of the core after the crack initiates. Notice the core immediately reverses its direction toward the at-rest-position at the beginning of the free response. This biface is 3 inches wide by 7.0 inches thick and fixed at the edge opposite the platform. These measurements yield a width-to-thickness ratio of 0.6.