Structural Response of Fluid Containing Tanks to Penetrating Projectiles (Hydraulic Ram) - A Comparison of Experimental and Analytical Results

This report presents the results of a study of (1) the fluid hydraulic ram pressures in a fluid-containing-tank caused by a penetrating projectile, and (2) the transient response of the entry and exit walls of the tank due to the fluid pressure. The experimental and analytical hydraulic ram and structural response programs at the Naval Weapons Center (NWC) and the Naval Postgraduate School (NPS) are briefly described. The computer analyses for the fluid pressure at the entry and exit walls and the transient entry and exit wall strains are described in detail. Comparisons are made of the predicted wall strains with the circular entry wall strains, measured at NPS, and the square exit wall strains, measured at NWC. Good agreement in the form of the strain histories is obtained, but the magnitudes of the predicted strains are smaller than those of the measured strains. This study contributes to the knowledge of the hydraulic ram phenomenon and associated fluid-structure interaction, and should provide some useful information for the design of aircraft fuel tanks.Naval Weapons Center, China Lake, California and the Joint Technical Coordinating Group/Aircraft Survivabilit