In one aspect, there is a composite skin for a tiltrotor aircraft including a first skin having a periphery defined by a forward edge, an aft edge, and outboard ends; a second skin; and a honeycomb core disposed between the first skin and the second skin, the honeycomb core comprised of a plurality of honeycomb panels positioned along the longitudinal axis of the first skin, the plurality of honeycomb panels having an array of large cells, each cell having a width of at least 1 cm; wherein the second skin and the honeycomb core have an outer perimeter within the periphery of the first skin.

A method of forming a structural honeycomb includes cutting and folding a substrate sheet according to predetermined cutting and folding patterns and fold angles that cause the sheet to form a honeycomb having cells that each have at least one face abutting, or nearly abutting, the face of another cell. The honeycomb is then stabilized by joining abutting, or nearly abutting, faces to hold the honeycomb together. The honeycomb may have a prespecified three-dimensional shape. The folding pattern may include corrugation, canted corrugation, or zig-zag folds. Joining may employ fixed and/or reversible joinery, including slotted cross section, tabbed strip, angled strip, integral skin, sewn, or laced. At least some folds may be partially-closed to create bends and twists in the honeycomb structure. Some surfaces of the honeycomb may be covered with a skin or face sheet. The substrate sheet may have flexible electronic traces.

A honeycomb structure has partition walls defining a plurality of hexagonal cells the partition walls are constituted by combining standard partition walls having a partition wall thickness in a range smaller than ±10% to an average partition wall thickness of the partition walls, wide partition walls having a partition wall thickness of +10% or more to the average partition wall thickness, and narrow partition walls having a partition wall thickness of −10% or less to the average partition wall thickness, and a non-standard partition wall ratio is in a range of 10% to 30% which is a ratio occupied by a subtotal number of non-standard partition walls obtained by adding the wide partition walls and the narrow partition walls in a total number of the partition walls which is obtained by adding the numbers of the standard partition walls, the wide partition walls and the narrow partition walls.

One aspect of a method of manufacturing a honeycomb core includes positioning a first thermoplastic columnar cell adjacent a second thermoplastic columnar cell, modifying a thermoplastic property of the first thermoplastic columnar cell, wherein the modified thermoplastic property permits joining a circumferential surface of the first thermoplastic columnar cell to a circumferential surface of the second thermoplastic columnar cell. The method also includes joining the circumferential surface of the first thermoplastic columnar cell having the modified thermoplastic property to the circumferential surface of the second thermoplastic columnar cell resulting in the honeycomb core.

A method for manufacturing an aeronautical sandwich panel with a honeycomb core and results in a core sealed to prevent infused resin from entering into the honeycomb core open cells while improving its mechanical properties, especially for curved or highly curved panels. In further embodiments, the invention proposes the automation of this process.

A composite sandwich panel comprises a first composite skin, a second composite skin, a hollow cell core between the first composite skin and the second composite skin, and a first over-crush edge region with a first edge. The first edge has a first thickness at least 40% less than a nominal thickness of the composite sandwich panel. The first over-crush edge region has a length of at least 0.25 inches over which a thickness of the composite sandwich panel decreases.

Described are novel composite structural panels and methods of forming such panels. In some examples, a method comprises wrapping a mandrel with a composite tape to form a composite tube. This wrapping operation allows forming composite tubular structures with any cross-sectional profiles defined by the mandrel. The wrapping is also used to control the fiber orientations in the composite tubular structures. The composite tube is then cut into composite tubular structures. In some examples, the composite tube is partially cured prior to the cutting, which allows removal of the mandrel while preserving the shape of the composite tube. This cutting operation allows forming composite tubular structures with different lengths, shapes, and orientations of the ends. The composite tubular structures are disposed on a support structure and are bonded to each other. In some examples, this bonding operation also involves final curing of the composite tubular structures.

A method of producing a cascade array and a cascade array is provided. The method includes: forming a plurality of strongbacks from a first thermoplastic material; forming a plurality of comb subassemblies, each said comb subassembly including one of the plurality of strongbacks and a plurality of vanes comprising a second thermoplastic material extending outwardly from the respective one of the plurality strongbacks; and attaching the plurality of comb subassemblies into a unitary structure to produce the cascade array.

A honeycomb structural body includes multiple cores, at least face sheet, and at least one reinforcement sheet. The multiple cores each have a honeycomb structure, and are bonded to each other with foamed adhesive in a direction in which the number of multiple pores formed by the honeycomb structure increases. The at least one face sheet is adhered to the multiple cores so as to cover the multiple pores. The reinforcement sheet is placed between the multiple cores and the at least one face sheet, at a position where the reinforcement sheet covers the foamed adhesive.

A honeycomb core construction that includes at least two honeycomb cores and a connection layer that is disposed between the honeycomb cores. The connection layer is configured so as to be gas-permeable, and has an adhesive for adhesively bonding to the honeycomb cores only in a region of the webs of the honeycomb cores.