Hydraulic Ram Effect on Composite Fuel Cell Entry Walls.

摘要

Catastrophic failure of a partially filled aircraft fuel cell due to impact and penetration by a high speed projectile often occurs due to a phenomenon known as hydraulic ram. The structural response of the fuel tank walls to hydraulic ram should be of vital concern to the designers of aircraft fuel cells. Considerable research has been conducted to determine the effects of hydraulic ram on metallic fuel cells, but very little attention has been given to fuel cells made with the new advanced composite materials. The purpose of this research is to examine the various effects of hydraulic ram on a graphite/epoxy wall when subjected to penetration by a .222 caliber projectile. Eight hydraulic ram tests are made on a clamped 11-inch square plate 0.067 inches thick at projectile velocities between 2600 and 2800 fps. The engineering properties of the laminate are determined both analytically and experimentally. The low velocity shots caused only slight damage to the plate. At the higher velocities, the hydraulic ram caused considerable damage, including total serverance of the plate from its clamped support over much of the outer perimeter. The results of this research illustrate the importance of the method of attachment of the composite wall at its boundaries. (Author)