Pressure tolerant fuel tank panels

Abstract

A pressure tolerant composite panel has an inner fiber reinforced layer, an outer fiber reinforced layer and an core disposed therebetween. In one embodiment of the invention, the inner layer has weakening structures incorporated at the peripheral edges thereof, and has an outer layer of a different and lower modulus of elasticity than the inner layer to provide some degree of elongation. When high internal forces are encountered, the weakening structures allow the inner layer to separate, with the outer layers stretching to absorb the forces without failure. Optionally, strengthening straps are position about the panel such that it is compartmentalized into discrete sections to contain damage in localized areas. In an alternative embodiment of the invention, the inner core is produced of a crushable material which has a yield strength sufficient to provide structural support under normal operating conditions. When a high pressure is encountered which exceeds the yield limit, the core is crushed to prevent force transmission to the outer layer. Such a composite panel assures survivability of the panel when subject to impact damage.