USA As Represented by Secretary of the Navy

Karin L Gipple

Liming W Salvino

Dale G Karr

A metal mold is machined via a computer numerically controlled wire-cut electrical discharge technique so as to describe a fractally profiled parallel grooves-and-ridges configuration. Fibers are placed along the mold's grooves. Using the mold combined with the fibers situate in its grooves, a first composite portion is resin transfer molded so as as to describe a complementary fractally profiled parallel grooves-and-ridges configuration, and to include, in its ridges, the fibers situate in the mold's grooves. Fibers are placed along the first composite portion's grooves. Using the first composite portion combined with the fibers situate in its grooves, a second composite portion is resin transfer molded so as as to describe a complementary fractally profiled parallel grooves-and-ridges configuration, and to include, in its ridges, the fibers situate in the first composite portion's grooves, and to effect secondary bonding of the first and second composite portions.

Fabrication of a fractally attributively delamination resistive composite structure

The inventive composite laminate has an interface profile which describes a fractally nonlinear contour. Inventive fabrication thereof typically includes computer numerically controlled wire-cut electrical discharge machining of a metal mold, resin transfer molding of a first composite portion using the metal mold, and resin transfer molding of a second composite portion using the first composite portion as a mold so that the interfacing surfaces of the composite portions are secondarily bonded to each other in conformal fashion. The interface surface of the second composite portion approximates the geometry of the metal mold surface, while the interface surface of the first composite portion approximates the inverted geometry of the metal mold surface. Each interface surface defines a multiplicity of lengthwise parallel grooves and ridges corresponding to the widthwise disordered undulations of the fractal interfacial profile. Both through-thickness strength and fracture toughness can be significantly increased by inventive practice of a composite laminate characterized by fractality of the interfacial profile.

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Arnold, MD, United States of America

Karin L Gipple