A modular mold for producing a panel including a panel of fiber reinforced material. The panel is configured to form hollow cells having an undulated trapezoidal cross-section. The mold includes at least three molding bars for forming each hollow cell. One of the molding bars has a trapezoidal cross shape. The other two molding bars have a triangular cross shape. The trapezoidal molding bar is located between the two triangular molding bars. The three molding bars when put together its cross-section forms the shape of the trapezoidal cross-section of the hollow cell.

A composite truss structure may have a first facesheet, a second facesheet, and a plurality of truss elements joined with the first facesheet and the second facesheet at nodes to form a one-piece structure. The composite truss structure may be formed by a method comprising preparing a dry fabric mold by: 1) placing a first dry fabric layer on a tool, 2) placing a first layer of fabric-loaded mandrels on the first dry fabric layer, 3) placing a second layer of the fabric-loaded mandrels on the first layer of fabric-loaded mandrels, and 4) placing a second dry fabric layer over the fabric-loaded mandrels. The method may further comprise infusing the dry fabric mold with a resin, and curing the resin to provide the nonflexible composite truss structure.

A process for manufacturing a composite structure includes: providing first mandrels, each first mandrel including a base and a plurality of projections arranged longitudinally along and projecting vertically out from the base; providing second mandrels; providing first ribbon plies, each first ribbon ply including a sheet of fibrous material; arranging each first ribbon ply with a respective first mandrel, the arranging of each first ribbon ply including substantially covering each surface of each of the projections of one of the first mandrels with a respective first ribbon ply; mating each second mandrel with a respective first mandrel such that each first ribbon ply is sandwiched between a respective first mandrel and a respective second mandrel; and curing resin disposed with the first ribbon plies to consolidate the first ribbon plies together and form a fiber-reinforced composite core structure of an acoustic panel.

A method may comprise: laying up a first plurality of plies of material comprising thermoplastic resin and fiber to form an inner skin preform, the inner skin preform being a continuous sheet including alternating peaks and valleys; laying up a second plurality of plies of material comprising thermoplastic resin and fiber to form an outer skin preform; and joining the inner skin preform to the outer skin preform.

A method for manufacturing an acoustic panel by welding of at least two acoustic components made of thermoplastic material, a thermal gradient being applied on the acoustic components during the welding operation so as to apply a temperature higher than the glass transition or melting temperature of the material on the area to be welded and so as to apply a temperature lower than or equal to the geometric stabilization temperature of the material on the parts furthest from the area to be welded.

A method for manufacturing a box-shaped structure for aircrafts, the structure extending along a longitudinal direction between a first longitudinal end and a second longitudinal end, and comprising: a first longitudinal wall; a second longitudinal wall facing the first wall and spaced from the first wall by a non-zero amount; a plurality of spars extending longitudinally and between said first wall and second wall; and at least one reinforcing rib arranged transversal to the spars at a transversal sector interposed between the first and the second longitudinal end; each spar has a spar cavity defining a lack of material extending longitudinally from an axial coordinate, which corresponds to the transversal sector, up to the second longitudinal end, so that the reinforcing rib can be easily inserted even after the integral coupling between the first wall, the second wall and the spars without compromising the structural properties of the box-shaped structure.

A method for manufacturing a box-shaped structure for aircraft, wherein the structure longitudinally extends between a first axial end and a second axial end and has a first longitudinal wall; a second longitudinal wall; a plurality of spars longitudinally extending between said first wall and second wall; a reinforcing rib transversal to the spars and inserted, between the first and second wall, in the area of a transversal sector interposed between the first axial end and the second axial end; the second wall comprises a main portion and a closing portion, which are coplanar to one another and define two distinct pieces with discontinuity and separated in the area of the transversal sector, so as to facilitate the insertion of the reinforcing rib without jeopardizing the structural properties of the box-shaped structure.

A method for manufacturing a panel including a plurality of partitions defining cells covered by at least one skin, the skin being formed by draping fibrous structures impregnated with a thermoplastic material on the upper edges of the partitions by automatic placement of fibers, the upper edges of the partitions and the fibrous structures being joined together with the aid of a localized heating device at the moment they are placed in contact, the method wherein the fibrous structures are draped with a draping tension on the interface between each edge of a partition and the deposited fibrous structure applying a shear stress of between 50% and 80% of the maximum shear stress before rupture of the interface.

A method for manufacturing a panel including a plurality of partitions defining cells covered by at least one skin, the skin being formed by draping fibrous structures impregnated with a thermoplastic material on the upper edges of the partitions by automatic placement of fibers, the upper edges of the partitions and the fibrous structures being joined together with the aid of a localized heating device at the moment they are placed in contact, the method wherein the fibrous structures are draped with a draping tension on the interface between each edge of a partition and the deposited fibrous structure applying a shear stress of between 50% and 80% of the maximum shear stress before rupture of the interface.

The invention relates to a monolithic structure in composite material manufactured starting from a fiber-reinforced prepreg material and comprises two walls facing each other and at least one interconnection element extending transversely between the walls, connected to them and delimiting with the latter respective elongated cavities; wherein the walls extend symmetrically at opposite sides of a direction; the interconnection element is a rib extending transversely to the aforesaid direction; at least one wall has a sandwich configuration and comprises two panels facing each other and at least one spar member, which extends transversely between the panels, is connected to them, delimits with the latter respective elongated cavities and extends transversally to the rib.