Vernon S Freeman

US Patent:

40863786, Apr 25, 1978

Filed:

Feb 20, 1975

Appl. No.:

5/551269

Inventors:

Clifford Y. Kam - Huntington Beach CA
Vernon L. Freeman - Huntington Beach CA
Allen P. Penton - Costa Mesa CA

Assignee:

McDonnell Douglas Corporation - Long Beach CA

International Classification:

B32B 300

US Classification:

428 36

Abstract:

Stiffened structural components, particularly integrally stiffened light weight shell structures, produced by molding astiffening member, preferably formed of a graphite-epoxy composition and having a so-called isogrid rib stiffening configuration, to a partially cured (B-stage) condition, injecting a suitable elastomer, e. g. a silicone, into the open spaces of the isogrid rib stiffener, to stabilize the partially cured composite during subsequent heat forming and curing operations, heat forming the resulting stiffening member to the required contour, e. g. for a cylinder into approximately 90. degree. arcuate isogrid panels, heat forming the skin of the shell structure by laying up a plurality of layers of a pre-impregnated tape within a cylindrical mold, installing a plurality, e. g. four, of the heat formed isogrid stiffening panels into the interior of the skin, co-curing the skin and the isogrid panels to form an integral stiffened shell structure, removing the cylindrical mold from the co-cured stiffened shell structure and removing the elastomer from the spaces between the isogrid rib stiffeners.