Safety Distance from Ricocheted Concrete Debris onto Concrete
When a building or ammunition explodes, many debris are scattered and collides with the ground and rebounds.
This is called ricochet phenomenon. Debris is dangerous because it contains large kinetic energy. The medium affects the
ricochet of the debris, and the air drag affects the debris flight. These should be considered to set a safety distance from debris
more exactly. In this study, FEM was used to investigate the ricochet about the concrete debris and medium. Also, the flight
trajectory was studied with the air drag force according to the Reynolds number. The ricocheted angle is very low when the
debris collides onto concrete. This is because the repulsion force in the direction perpendicular to the ground is weak when the
debris collide onto the concrete. Therefore, the effect of increasing the travel distance of the debris is very small from ricochet.
Index Terms - Ricochet, Drag force, Concrete, Safety distance