Figure 3.
High-speed videos taken under cross-polarized light of arrows impacting ballistics gel illustrates how materials react to puncture events at high speeds. The frames are from high-speed video of a puncture event, taken at 20 000 fps, with an arrow travelling at 12.2 m s−1. Stress waves are clearly visible 3.2 ms after impact and the arrow reached its final penetration depth by 12.9 ms. However, the gelatin did not begin to macroscopically deform until 18.3 ms after impact. Finally, the deformation of the gelatin resulted in the arrow being expunged 48 ms after initial impact (electronic supplementary material, Movie S1).