RU2250824C1 - Method of production of a trilaminar panel out of a reinforced plastic and a filler out of tubular elements - Google Patents

Abstract

FIELD: shipbuilding; methods of production of large-sized load-carrying structures with curvilinear surfaces of two kinds curvature.

SUBSTANCE: the invention is dealt with shipbuilding, in particular, with methods of production of large-sized load-carrying structures with curvilinear surfaces of a two kinds of curvature. The method of production of the trilaminar panel out of a reinforced plastic provides for molding of the lower load-carrying layer, stacking of tubular elements of the filler closely to each other, molding of the upper load-carrying layer atop of them and hardening of the all elements of the trilaminar panel. The technical result of the invention is an increase of the load-carrying capacity of the trilaminar panel having rather big overall dimensions and an irregular shape of the curvilinear outer surfaces at simultaneous decrease of labor input of its production. The method consists in the following sequence of production operations: first from the previously molded and hardened tubular elements of the filler produce blocks. Further the blocks are place in a mold. The blocks are pressed down to the effective surface of the mold and fixed in respect to each other. In the clearance formed between the blocks they insert the previously formed, but still not hardened billets of driven tubular elements of the filler with their consequent hardening. Atop of the so formed solid layer of the filler mould the upper load-carrying layer of the trilaminar panel. After hardening of the upper load-carrying layer and also fixation of the curvature of the trilaminar panel billet it is taken out from the mold and on the opposite side of the layer of the filler mould the lower load-carrying layer of the trilaminar panel with its following hardening.

EFFECT: the invention ensures an increase of the load-carrying capacity of the trilaminar panel having rather big overall dimensions and an irregular shape of the curvilinear outer surfaces at simultaneous decrease of labor input of its production.

6 cl, 16 dwg

Description

The invention relates to shipbuilding and relates to the manufacturing technology of large-sized bearing hull structures with curved surfaces of double curvature, for example, aerodynamic structures of hovercraft. The invention can also be used in aircraft construction.

A known method of manufacturing a three-layer panel of reinforced plastic with a filler of tubular elements, which consists in the following sequence of technological operations: forming the outer bearing layers of a three-layer panel, each in its own form; curing them; the location between them with a certain pitch of the blanks of the tubular filler elements; their bloating by supplying compressed air to their internal cavities until they come into contact with the internal surfaces of both bearing layers; their curing and filling the gaps between the foam-reinforced plastic tubular elements thus formed by introducing a foamable polymer composition into these gaps [1].

Due to the fact that the side walls of tubular elements made of reinforced plastic, which are formed in the internal volume of a three-layer panel manufactured in this way, which function as internal stiffeners connecting its load-bearing layers to each other, have not a flat, but a cylindrical shape, the bearing capacity of such a three-layer panel under the action of External lateral loads are not high.

Known methods for the manufacture of three-layer panels of reinforced plastic with filler from tubular elements, which are based on the following common sequence of basic technological operations: forming the outer bearing layers of a three-layer panel, each in its own form; the location between them close to each other blanks of tubular filler elements; inflating them by supplying compressed air into their internal cavities until they come into contact with the internal surfaces of both bearing layers and with the side walls of adjacent tubular elements and curing the entire billet of a three-layer panel [2], [3], [4].

When implementing these methods of manufacturing a three-layer panel, the internal reinforcing ribs made of reinforced plastic, formed by the side walls of adjacent tubular filler elements glued together, can have a flat shape. This significantly increases the bearing capacity of the three-layer panel under the influence of external transverse loads.

However, it is obvious that the process of forming internal reinforcing ribs of reinforced plastic in accordance with these methods of manufacturing a three-layer panel is uncontrollable, since it occurs during the process of blowing up the blanks of the tubular filler elements with compressed air in a closed internal volume between the blanks of the supporting layers being manufactured in their shapes three-layer panel. The consequence of this may be the emergence of various subsequently fatal defects of the aggregate of the manufactured three-layer panel, such as, for example, the presence of undisturbed folds of the side walls of the shapeless blanks of tubular elements during their bloating, deviations from the calculated step of the location of the internal stiffeners, deviations from the calculated contact angle of the planes of the internal stiffeners to the bearing layers of a three-layer panel, etc. These defects do not allow to fully realize the calculated bearing capacity of the three-layer panel under the influence of external transverse loads.

It should also be added that, due to the use of compressed air filler for forming tubular elements, for the implementation of all the above methods of manufacturing a three-layer panel [1], [2], [3], [4], the use of expensive molds having a large bending stiffness, providing the perception of large internal pressures without noticeable bending deformation of their shells. This significantly reduces the manufacturability of these methods.

These shortcomings are largely devoid of the known method of manufacturing a three-layer panel of reinforced plastic with a filler of tubular elements, which is the prototype of the proposed method. It consists in the following sequence of technological operations: molding on the surface of the form of the lower supporting layer of a three-layer panel; molding tubular filler elements of a three-layer panel by wrapping foam bars with a soaked binder reinforcing material; laying thus formed blanks of tubular filler elements close to each other over the blank of the lower supporting layer; molding on top of the thus formed continuous layer of aggregate of the upper bearing layer and simultaneous curing of the entire preform of the three-layer panel [5].

Indeed, in the manufacture of a three-layer panel of reinforced plastic in accordance with this method, internal reinforcing ribs of reinforced plastic can be obtained, connecting the supporting layers of the manufactured three-layer panel with each other, with geometric and mechanical characteristics that more accurately correspond to the calculation, which helps to increase the bearing capacity of the three-layer panels under the action of external lateral loads. And the possibility of implementing this method using only one form, without the use of an expensive mold, makes this method much more technological.

However, this method of manufacturing a three-layer panel of reinforced plastic has significant disadvantages. Due to the need to perform all technological operations for the manufacture of the panel, including the molding of all tubular elements of the filler, in one technological cycle, i.e. prior to the simultaneous curing of fiberglass of all its elements, this method does not provide any opportunities for the manufacture of three-layer panels with relatively large overall dimensions and for the organization of operational control of the technological process of manufacturing a three-layer panel, which is one of the most important conditions for ensuring high load-bearing capacity of the manufactured three-layer panel. Achieving the relatively low laboriousness of manufacturing a three-layer panel due to the partial mechanization of individual technological operations of its manufacture by this method is also problematic.

The aim of the invention is to increase the bearing capacity of a three-layer panel made of reinforced plastic with a filler of tubular elements having relatively large overall dimensions and a complex shape of curved outer surfaces, while reducing the complexity of its manufacture.

This goal is achieved by the fact that in the method of manufacturing a three-layer panel of reinforced plastic with a filler of tubular elements, including forming the lower bearing layer, laying close to each other the tubular elements of the filler, molding over them the upper bearing layer and curing all the elements of the three-layer panel, the following the sequence of basic technological operations: first, blocks are made from preformed and cured tubular filler elements, Commercially curvature of the outer surfaces, identical to the curvature of the respective surfaces of manufactured sandwich panel; the blocks are laid out in a mold, the working surface of which has a curvature identical to the curvature of the corresponding surface of the manufactured three-layer panel; the blocks are pressed against the working surface of the mold and fixed relative to each other; in the gaps formed between the blocks, they are introduced close to the side faces of adjacent blocks of preformed, but still uncured blanks of the downhole tubular filler elements with their subsequent curing; on top of the continuous aggregate layer thus formed, an upper supporting layer of a three-layer panel is formed; after curing of the upper carrier layer of the three-layer panel, as well as fixing the curvature of the thus obtained preform of the three-layer panel, it is removed from the mold and the lower carrier layer of the three-layer panel is formed on the opposite side of the filler layer with its subsequent curing.

In this case, blocks of pre-cured tubular elements are made by gluing them along adjacent lateral faces in a special mold, the working surfaces of which are identical to the corresponding surfaces of the manufactured three-layer panel.

In this case, before laying the pre-cured rectilinear tubular elements in the mold for the manufacture of blocks, cuts are made in them, and each cut partially cuts both side faces and completely one of the faces adjacent to the bearing layers of the manufactured three-layer panel, and the cut planes of each tubular element are located with offset relative to the planes of cuts of adjacent tubular elements of the block.

Moreover, in the manufacture of blanks for downhole tubular elements, they are given a plan in shape identical to the configuration in terms of the corresponding gaps between adjacent blocks of tubular filler elements of the manufactured three-layer panel.

In this case, when forming the upper carrier layer of the manufactured three-layer panel, it is first formed in the sections between the clamps, which press the blocks of tubular filler elements to the working surface of the mold, and then after curing these sections and transferring the clamps to the cured sections of the upper carrier layer, the upper carrier is formed. layer on the missed areas with their subsequent curing.

In this case, fixing the curvature of the workpiece of the manufactured three-layer panel before removing it from the mold is carried out by shaping the panel set elements to its upper bearing layer.

Due to the fact that, in accordance with the proposed method, the manufacturing process, up to curing, the bulk of the tubular filler elements is outside the time frame of the molding process, in the manufacture of tubular elements can be applied mechanized molding methods and curing blanks of tubular elements in special molds under pressure. This helps to increase the bearing capacity of the manufactured three-layer panel, as it improves the mechanical characteristics of the reinforced plastic tubular elements, and reduces the overall complexity of the manufactured three-layer panel.

Due to the fact that, in accordance with the proposed method, curvilinear blocks having the curvature of the outer surfaces identical to the curvature of the corresponding surfaces of the manufactured three-layer panel are made from prefabricated rectilinear tubular filler elements, and then these blocks are used to form the filler layer of the three-layer panel, a sharp decrease the complexity of the process of forming directly the most curved three-layer panel, which allows using claimed method successfully curved sandwich panels manufactured with relatively large dimensions and thus to closely functional control of workmanship, which also contributes to increase the bearing capacity of the manufactured sandwich panel.

Due to the fact that, in accordance with the proposed method, in the gaps formed between the blocks of tubular elements after they are laid out on the surface of the mold for forming a three-layer panel, preformed, but still uncured blanks of downhole tubular filler elements are laid close to the side faces of adjacent blocks by curing them, it is possible to manufacture a three-layer panel with double curvature when the size of the manufactured three-layer panel in the direction transverse to the pipe axes The specific aggregate elements are different in different places along the length of these tubular elements.

Due to the fact that, in accordance with the proposed method, the lower supporting layer of the three-layer panel, usually corresponding to the outer surface of the manufactured three-layer panel, is formed last, when all the elements of the three-layer panel are already molded, and its shape is fixed, it is possible to finally check the quality manufacturing the entire filler layer of the three-layer panel and, if necessary, eliminating the identified defects. This allows you to increase the strength of the connection of the filler with the outer bearing layer, as well as the quality of the outermost bearing layer of the three-layer panel, which also helps to increase the bearing capacity of the manufactured three-layer panel.

It should also be added that, in accordance with the proposed method, the outer supporting layer of a three-layer panel can be molded even after connecting two or more blanks of similar three-layer panels to each other, each brought to the stage preceding the formation of the outer bearing layer, with in order to obtain a single, common for them, the outer bearing layer, which, due to the exclusion of the corresponding connecting elements, helps to reduce weight and increase the bearing capacity of the housing reinforced plastic construction.

The proposed method of manufacturing a three-layer panel of reinforced plastic with a filler of tubular elements is illustrated schematically by drawings, which depict:

figure 1 - pre-made rectilinear tubular filler elements;

in FIG. 2 and 3 - pre-made rectilinear tubular elements at the time of their laying in a special mold for the manufacture of curved blocks of tubular filler elements;

in FIG. 4 and 5 - a special mold at the time of pressing the curved block of tubular aggregate elements;

in FIG. 6 and 7 - the finished curved block of tubular filler elements;

in FIG. 8-10 - the form, together with the workpiece of the three-layer panel located on its working surface, after the completion of the first stage of forming the upper carrier layer of the three-layer panel;

in FIG. 11-13 - the form, together with the workpiece of the three-layer panel located on its working surface after completion of the second stage of forming the upper carrier layer of the three-layer panel;

in FIG. 14 and 15 - the form, together with the workpiece of the three-layer panel located on its working surface, after molding to its upper bearing layer the elements of the set of the three-layer panel;

in Fig.16 is located on the stands completely finished three-layer panel after completion of the formation of its outer bearing layer.

The practical implementation of the proposed method is shown by the example of manufacturing an inner three-layer fiberglass panel with a filler from tubular elements of the nozzle ring segment of the ship’s hovercraft propeller, which is a section of this nozzle ring limited in the direction along the circumference of the nozzle ring by two end planes, passing through the axis of rotation of the propeller located inside the nozzle ring.

Of the rectilinear tubular elements 1 (Fig. 1) prefabricated in the specialized production, each of which is a fiberglass pipe of rectangular cross section with a foam core, blocks are made having the curvature of the outer surfaces, both in the direction of the axes of the tubular elements and in the perpendicular direction, identical to the curvature corresponding surfaces of the manufactured three-layer panel. To do this, their adjacent side faces 2 are smeared with an adhesive composition, pressed by their side faces 2 to each other and placed in a special mold 3 (Figs. 2, 3), the working surfaces 4 of which are identical to the corresponding surfaces of the manufactured three-layer panel.

After closing the mold 3 (Figs. 4 and 5), the tubular elements 1 placed in it are glued together and, bending within the limits of elastic deformation, acquire the desired curvilinear shape (Figs. 6, 7). In this case, the adhesive layers between the tubular elements 1, polymerized after their curvature in the mold 3, ensure the fixation of the obtained curved shape of the blocks 5 and after they are removed from the mold 3.

In those places where the relatively high bending stiffness of the fiberglass tubular elements 1 does not allow them to bend to the required curvature of the corresponding block 5 without destruction, cuts 6 are made in the tubular elements 1, and each cut 6 partially cuts both side faces 2 and completely one of the faces 7 adjacent to the bearing layers of the manufactured three-layer panel. And the plane of the notches 6 of each tubular element 1 are offset with respect to the planes of the notches 6 of the adjacent tubular elements 1 of block 5.

The curvilinear blocks 5 of the filler tubular elements 1 made in this way, after lubricating their side faces 8 (Fig. 7) with adhesive, are laid out in the form of 9 (Figs. 8-10), the working surface 10 of which has a curvature identical to the curvature of the outer surface of the filler of the manufactured three-layer panel , and pressed against it, fixing them relative to each other.

To press the blocks 5 to the working surface 10 of the mold 9, for example, as shown in Figs. 8-13, special folding U-shaped brackets 11, special clamping beams 12 and wedges passed under them, pivotally mounted on the end walls of the mold 9 can be applied 13, providing with the help of U-shaped brackets 11 tight pressing of the clamping beams 12 together with the blocks 5 of the tubular elements 1 to the working surface 10 of the mold 9.

Since the internal, i.e. facing the propeller, the surface of the nozzle ring having an aerodynamic profile, in different sections by planes parallel to the plane of rotation of the propeller, has different radii of curvature, and the arc lengths on the inner surface of the nozzle ring segment corresponding to these radii are also different. Due to this, the blocks 5 of tubular elements 1 having the same width along their entire length, laid on the working surface 10 of the mold 9 close to each other in cross-section by the plane of rotation of the propeller (FIGS. 10, 13), where the width of the inner three-layer panel of the nozzle ring segment is minimal , since it corresponds to the minimum radius of curvature of its surface facing the propeller (see Fig. 16), in all other sections by planes parallel to the plane of rotation of the propeller, in the nose and in the stern from it, they form gaps (phi .8, 11) breaking the continuity of the filler layer manufactured sandwich panel. These gaps have the form of wedges with sharp angles directed towards the plane of rotation of the propeller, expanding as it moves toward the nose and tail of the nozzle ring profile.

To fill these gaps, tiles of rectangular cross section with a height equal to the height of the foam core cores of the filler tubular elements 1 and a variable width in accordance with the configuration in terms of the corresponding gaps between adjacent blocks 5 of the filler tubular elements 1 are cut from tile foam. Foam bars are wrapped with impregnated binder reinforcing material and the thus obtained blanks of the downhole tubular elements 14 (Fig. 8) of the filler are introduced into the above-mentioned gaps close to the side faces of adjacent blocks 5 of the tubular elements 1. After the fiberglass of the downhole tubular elements 14 has cured, all the blocks 5 are connected along its side faces 8 with each other with the formation of a continuous layer of aggregate manufactured three-layer panel.

On top of the continuous aggregate layer thus formed, the upper carrier layer 15 (Figs. 9, 12, 13) of the three-layer panel is formed. First, sections 16 (Figs. 8, 9) of the upper carrier layer 15 are formed in the spaces between the pressure beams 12, and then after they are cured and the pressure beams 12 (Figs. 11-13) are transferred to the cured sections 16, the missing sections are formed. 17 (Fig. 11) of the upper carrier layer 15, with their subsequent curing.

The curvature of the three-layer panel blank obtained in this way is fixed before removing it from the mold 9 by molding to its upper bearing layer 15 two U-shaped stringers 18, 19 (11, 12), by molding special foam plastic holders 20 installed on its surface, 21, as well as ribs 22 (Fig. 14-16) and the brace 23, 24 of the spars, using the molding squares 25.

After curing of the U-shaped stringers 18, 19 and shaping squares 25 connecting the rib 22 and the braces 23, 24 of the side members between themselves and with the upper bearing layer 15, the workpiece of the inner three-layer panel of the nozzle ring segment is removed from mold 9, turned over and mounted on special supports 26 (Fig. 16) set down. Then, on the free surface of the filler layer 27 of the three-layer panel, its lower carrier layer 28 is formed, which is for the manufactured three-layer panel its outer carrier layer, followed by curing.

The proposed technical solution improves the efficiency of the use of three-layer panels of reinforced plastic in ship bearing hull structures with complex curved outer surfaces.

Sources of information

1. Auto USSR No. 235564, M.cl. B 63 d; B 63 c, publ. 01/16/1969, Bull. No. 5.

2. USSR patent No. 308562, M.cl. B 29 G 5/00, publ. 07/01/1971, Bull. No. 21.

3. The patent of Germany No. 1275279, M.cl. B 29 D, publ. 06/26/1969.

4. E.S. Kolodyazhny, G.A. Pavlov, M.I. Lichman, P.F. Cheplygin. Fiberglass shipbuilding superstructure - “Shipbuilding Technology”, 1978, No. 7, p. 40.

5. Auth. St. USSR No. 318502, M.cl. 63 V 5/24, publ. 10/28/1971, Bull. Number 32.

Claims (6)

1. A method of manufacturing a three-layer panel of reinforced plastic with a filler of tubular elements, comprising forming the lower carrier layer, laying close to each other the tubular filler elements and forming on top of them the upper carrier layer, characterized in that the first of the preformed and cured tubular filler elements blocks are made having the curvature of the outer surfaces identical to the curvature of the corresponding surfaces of the manufactured three-layer panel, the blocks are laid out in the form, the working surface of which has a curvature identical to the curvature of the manufactured three-layer panel, the blocks are pressed against the working surface of the form and fixed relative to each other, into the gaps formed between the blocks, they are introduced close to the side faces of adjacent blocks preformed, but still not solidified tubular blanks aggregate elements with their subsequent curing, on top of the thus formed continuous layer of aggregate form the upper carrier layer layer panel, after curing of the upper carrier layer, and fixing its curvature sandwich panel is removed from the preform mold and on the opposite side of the filler layer is formed lower carrier layer sandwich panel with its subsequent curing. 2. The method according to claim 1, characterized in that the blocks of pre-cured tubular elements are made by gluing them along adjacent side faces in a special mold, the working surfaces of which are identical to the corresponding surfaces of the manufactured three-layer panel. 3. The method according to claim 1 or 2, characterized in that before laying the pre-cured rectilinear tubular elements in the mold for the manufacture of blocks, cuts are made in them, and each cut partially cuts both side faces and completely one of the faces adjacent to the bearing the layers of the manufactured three-layer panel, and the cut planes of each tubular element are offset with respect to the cut planes of adjacent tubular elements of the block. 4. The method according to claim 1, characterized in that in the manufacture of blanks for downhole tubular elements in the plan they are given a shape identical to the configuration in terms of the corresponding gaps between adjacent blocks of tubular filler elements of the manufactured three-layer panel. 5. The method according to claim 1, characterized in that when forming the upper carrier layer of the manufactured three-layer panel, it is first formed in sections between the clamps, which ensure that the blocks of tubular filler elements are pressed against the working surface of the mold, and then, after curing these sections and transferring the clamps on the cured sections of the upper bearing layer, perform the molding of the upper bearing layer on the missed sections with their subsequent curing. 6. The method according to claim 1, characterized in that the fixation of the curvature of the workpiece manufactured three-layer panel before removing it from the form is performed by molding to its upper bearing layer of the elements of the panel set.

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