Airbus Corporation

Otkrytoe Aktsionernoe Obschestvo “Kazansky Nauchno-Isledovatelsky Institut Aviatsionnoi Tekhnologii”

Otkrytoe Aktsionernoe Obschestvo

Otkrytoe Aktsionernoe Obschestvo “Kazansky Nauchno-Isledovatelsky Institute Aviatsionnoi Tekhnologii”

Niaz Irekovich Akishev

Ildus Muhametgaleevich Zakirov

Alexandr Vladimirovich Nikitin

A method for production of sandwich panels having a zigzag corrugated core made from sheet material to be used in aircraft construction, shipbuilding, and other branches of industry. The method improves the quality and ease of sheet blank folding into a 3-D relief structure. Folds are made in the sheet blank at locations of crimp zigzag lines protrusions and recesses. Holes are punched in the sheet with a diameter of the holes being greater than or equal to a sheet blank bending radius.

Method for production of sandwich panels with zigzag corrugated core

The invention can be defined in its most general form as a technology for production of corrugated structures from foliated composite materials and can be used for production of sandwich panels used in aircraft construction, shipbuilding, and in building units. Method for production of sandwich panel core from composites including the placing of the blank from reinforcing material, the impregnation of the blank with binder obtaining thus the prepreg, the hardening of the binder in the course of hot-pressing and obtaining of the plane semifinished-blank in the form of a set of relatively rigid parts having the form of the core ridges and detached of one another for some distance, the after-deformation of the semifinished-blank and obtaining the core relief with the required geometrics, and the final hardening of the applied binder involves the impregnation of the reinforcing material with hinder along the full surface of the blank, the heat supply for hardening of the binder in the obtained prepreg within the bounds of said parts, and creation of conditions slowing down the process of hardening along the prepreg zones between said parts. The width of the prepreg zones between the parts having the form of the core ridges is provided in the course of hot-pressing and is not less than double radius of the blank material bending at these parts when shaping the core.

Method for production of sandwich panel core from composites

The invention can be defined in its most general form as a 3-D light core from sheet material, especially from 'NOMEX' polymeric paper, and can be used in production of sandwich panels as applied in aircraft production, construction and other branches of industry. With the aim to improve the core mechanical and unit weight properties, the paper base is perforated thereby increasing the base-binder bonding strength, whereof the binder is applied onto both sides of the base to increase its structure rigidity, owing to bonding of binder layers in-between at the locations of the holes. The quantity of the holes and their diameter are defined in a formula.

Sandwich panel core

The invention can be defined in its most general form as a building unit, namely the sandwich panel with light core from corrugated sheet material in the form of zigzag crimp, and can be used in aircraft construction, as well as in shipbuilding and construction. Making use of the claimed invention will improve the weight efficiency, the strength and the manufacturability of the panel. The beneficial effect is attained due to the fact that the plane slanting ridges are connected along the protrusion and recess zigzag lines by means of curvilinear parts, whose radius is not less than the core material thickness, whereby along said parts is a line perforation enabling the adhesive material to get into the holes of the perforation in the course of core-skins assembling.

Sandwich panel

The invention can be defined in its most general form as a device for sheet material corrugation by means of bending and can be used in production of light core for sandwich panels, and elements of heat-exchange apparatus. The device includes the pivotedly connected in-between shaping and auxiliary systems of dies () and the drive for their transformation including the system of vacuumization and the chamber () made of flexible gas-proof material where the latter of said systems is fixed. Used to set the system of shaping dies () into its initial plane state is the mechanism made in the form of rigid chamber with the perforated cap () providing the possibility to connect the chamber to the system of vacuumization. The device also includes the subsidiary flexible removable vacuum chamber () wherein the blank () from sheet material is placed in contact with the shaping system of dies (). Said chamber and the transformation drive chamber have a common wall rigidly connected to the shaping and auxiliary systems of dies () at locations of their pivot connection.

Device for sheet material corrugation

The invention can be defined in its most general form as a device for sheet material corrugation by means of bending and can be applied in the devices for production of single curvature folded core used in production of aircraft and craft curvilinear panels. The invention has for its object to broaden the technological capabilities. For that the mandrel is made in the form of a set of alternating rows of plane elements () made in the form of trapeziums () and isosceles triangles () fixed on the flexible material of the base () forming thus the gap-pivots between the elements. At the same time the bases of the triangular elements () face each other in pairs along the bending lines while said bending lines correspond to the protrusions lines of the core folded structure. The base of the triangular elements () is the function of the folded core block curvature radius and the geometrical parameters of the zigzag crimp structure. The width of the gap-pivots is taken so that to provide the folding of the mandrel together with the blank forming thus the single curvature zigzag corrugated structure with the lateral direction of crimps.

Foldable mandrel for production of a single curvature folded core for a sandwich panel

The device contains the transformable mandrel () made of plane elements () pivotedly connected in-between with the use of gas-proof fabric (), the means for preliminary and final mandrel transformation including the flexible vacuum chamber and traverse-pusher () with the drive (), and the mechanism for putting the transformable mandrel into its initial plan state made in the form of two parallel slabs () with the drive for their reciprocal travel (). The means for preliminary mandrel transformation is made in the form of the system of pushers placed in rows on the lower and the upper slabs with individual drives. The perforations in the slabs provide the possibility for the pushers to interact with the transformable mandrel placed between the slabs whereas the mandrel with sheet blank article is put into the vacuum chamber.

The invention can be defined in its most general form as the method for sheet material corrugation and can be used for production of aircraft curvilinear sandwich panel folded structure light corrugated core. With the aim to broaden the technological capabilities the corrugated blank is compressed from its sides to joining of ridges providing in its lateral section the curvature radius defined by the curvilinear folded structure design parameters and fixed in such condition block is thermally treated for inner stresses relief in the article material whereupon it is stretched to the curvilinear folded structure parameters given.

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Kazan, Russia

Niaz Irekovich Akishev