Experiments were conducted in the pool at Area 2 of the remote test site to investigate the effect of a parachute, impact velocity (12 to 35 m/s), impact angle (30^o and 90^o), and water depth (0.2 and 1.2 m) on the penetration of a rigid body projectile into underwater sediments. The 76-mm-diameter, 630-mm-long aluminum penetrator weighed 4.75 kg. A compressed-gas gun mounted on a structural steel platform launched the projectile into the pool, which contained a 2.4-m-deep layer of San Francisco Bay mud covered by a layer of water. A high-speed cine camera (500 frames/s) monitored the flight (in air) of the projectile and was used to determine the flight path of the projectile, the velocity of the projectile as it impacted the water surface, and the condition of the parachute upon water entry. Underwater break-wire screens were used to measure velocity and to trace the trajectory of the projectile during underwater travel.

Antoun, T., and M. Sanai, "Penetration of a Rigid Body Projectile into Underwater Sediments," Proceedings of the 65th Shock and Vibration Symposium, Volume II, held in San Diego, October 31-November 3, 137-154 (1994).

Dr. James K. Gran Associate Lab Director

Phone (650) 859-4472 e-mail: jkgran@unix.sri.com

Dr. James D. Colton Laboratory Director

Phone (650) 859-2208 e-mail: jcolton@unix.sri.com