RU2256556C2 - Method of production of a filler with a zigzag corrugated structure - Google Patents

Abstract

FIELD: building industry; aircraft industry; transport mechanical engineering; methods of production of corrugated constructions with a folded structure.

SUBSTANCE: the invention is pertaining to the field of the methods of production of corrugated constructions with a folded structure used in the capacity of a filler of multilayered panels. The invention may be used in production of aircrafts, building industry and transport mechanical engineering. The invention provides, that the process of shaping a detail with a zigzag corrugated structure is preceded with a local slackening of a billet rigidity along the marking lines in the areas of a supposed bending by shaping of grooves along the zigzag lines of profile peaks determining a position of the peaks of the structure, and along the cuttings of the saw-type lines determining the peaks along these lines in the structure - on one side of the billet and along the zigzag lines of the pits of the structure - on the opposite side of the billet. On the all points of the lines intersection on the billet marking lines form pits. Slackening of rigidity of the billet may be conducted by a piercing of through holes of a small diameter along all the marking lines. After shaping of grooves and pits the billet may be given a slant relief according to the given zigzag corrugated structure. Then the shaping of the zigzag corrugated structure is realized by an additional pressure of the billet with the produced slant relief up to the structure with the given density of the relief. The method allows to receive with a high accuracy of a filler with the zigzag corrugated structure from the solid-sheet materials.

EFFECT: the invention ensures production with a high accuracy of a filler with the zigzag corrugated structure from the solid-sheet materials.

5 cl, 5 dwg

Description

The invention relates to the technology of manufacturing corrugated structures with a folded structure from sheet materials: paper, cardboard, metals. It can be used in the manufacture of aircraft, transport engineering, construction.

A known method of manufacturing a zigzag corrugation, implemented in a device protected by RF patent No. 2118217, MKI B 21 D 13/00. Device for corrugating sheet material, V.I. Khaliulin, I.V. Double-eyed, publ. Bull. No. 24 dated 08/27/1998 - [1]. The method consists in the fact that the sheet preform is installed in the forming unit in the form of two transformable matrices forming an airtight cavity, and the product is formed by creating a vacuum in the airtight cavity.

The disadvantage of this method is the low accuracy of the Z-shaped corrugation due to the large influence of the positioning accuracy of the transformed matrices in relation to each other, since they are multi-link mechanisms with a large number of hinges, and a slight deviation of any link from the nominal position leads to a distortion of the shape of the incipient relief and, as a consequence, to the low accuracy of the product, in addition, the formation of significant radii of rounding along the edges of the bend.

A known method of manufacturing a filler with a structure of the type of a Z-shaped corrugation, which consists in laying impregnated with a binder sheet of reinforcing fabric on a transformable mold-setting mandrel, sealing with a vacuum bag, putting the mandrel in a relief state and molding the product under atmospheric pressure - (RF Patent No. 1706148, MKI V 32 V 15/00, V 29 C 59/00. Device for the manufacture of products of complex profile from composite material, V. I. Khaliulin, V. E. Desyatov, publ. Bull. No. 16 dated 06/12/1996) - [2].

The disadvantage of this method is that it allows the molding of products only from composite materials and is not applicable when used as a blank solid materials.

A known method of manufacturing a filler type Z-shaped corrugation, consisting of the preliminary formation of the corrugation with a trapezoidal guide and a linear generatrix, the transverse opposite inversion of the corrugation to form a given mesh relief - (RF Patent No. 2100120, MKI B 21 D 13/00, 13/02. A method of manufacturing a zigzag corrugation (options) and a device for its implementation, V.I. Khaliulin, EA Skripkin, publ. Bull. No. 36 dated 12/27/1997) - [3].

The disadvantage of this method is the low accuracy of the relief of the Z-shaped corrugation due to the fact that in the places of bending rounding with a radius of significant magnitude is formed.

A known method of manufacturing a filler of a folded structure such as a Z-shaped corrugation from composite material, adopted as a prototype, including laying a flat sheet of fabric, weakening the stiffness of the workpiece by applying a binder to the fabric discretely in areas forming the side faces of the filler, to obtain strips of non-impregnated fabric along the lines connecting the side faces, curing the binder and deforming the workpiece according to the cell profile - (RF Patent No. 2057647, MKI B 29 D 9/00, Method for the manufacture of aggregate from composite material V.I.Haliulin, V.E.Desyatov, published on 10.04.1996 Bul №10 g.) -. [4].

The disadvantage of this method is its limited technological capabilities, since it is applicable only to the manufacture of aggregate from composite materials.

The invention solves the problem of manufacturing a filler with a zigzag corrugated structure of high accuracy from solid materials.

The problem is solved in that according to the method of manufacturing a filler with a zigzag corrugated structure for a multilayer panel, including local weakening of the stiffness of the workpiece along the marking lines in the areas of the proposed bending and shaping the workpiece according to the shape of the cells of the zigzag structure, local weakening of the stiffness on the hard workpiece is performed by forming grooves along the zigzag grooves the lines of the protrusions that determine the position of the protrusions of the structure, and along the segments of the sawtooth lines, determine dividing the protrusions along these lines in the structure, on one side of the workpiece and along the zigzag lines of the depressions that determine the position of the depressions of the structure, and along the segments of the sawtooth lines that define the depressions along these lines in the structure, on the other side of the workpiece, form depressions at all intersection nodes on the layout of the workpiece zigzag lines of the protrusions and zigzag lines of the depressions with sawtooth lines on the corresponding side of the workpiece.

In addition, after the formation of grooves and recesses, the workpiece can be given a gentle relief according to a given zigzag corrugated structure, while the maximum allowable relief depth H _max is determined by the formula:

where δ _p is the maximum allowable uniform elongation, S ₀ , L ₀ , V ₀ are the marking parameters on the scan, namely: S ₀ is the step between the sawtooth lines; L ₀ is the step between the zigzag lines; V ₀ - the amplitude of the zigzag lines on the markup.

Then the formation of a zigzag corrugated structure is carried out by squeezing the workpiece with the obtained gentle relief to the structure with a given density of relief.

According to the method of manufacturing a filler with a zigzag corrugated structure for a multilayer panel, including local weakening of the stiffness of the workpiece along the marking lines in the areas of the proposed bending and shaping of the workpiece according to the shape of the cells of the zigzag structure, local weakening of the stiffness on the hard workpiece is carried out by punching holes of small diameter along the zigzag line zigzag lines of depressions and sawtooth lines of a given zigzag corrugated structure with one rd party piece.

The invention is illustrated in figure 1 - figure 5, where:

Figure 1 - Zigzag corrugated structure (pleated aggregate with a structure of the type "z-corrugation").

Figa-2B - Scan zigzag corrugated structure: a - marking structure; b - sections A-A, B-B, C-C, D-D sweep of a zigzag corrugated structure with grooves; c - fragments of structures I and II with depressions in nodal zones.

Figa-3B - Harvesting with a gentle zigzag relief with its subsequent compression to the structure with a given density of relief: a - the workpiece in a shallow relief; b - shaping the relief by squeezing to the desired density of the relief; c - finished part with a zigzag corrugated structure.

Figa-4b - Harvesting with the weakening of rigidity by punching holes of small diameter along all lines of the marking: a - scan; b - section AA, B-B sweep with holes.

Figure 5 - Pattern of the formation of a gentle zigzag relief by stamping: a is a fragment of a workpiece with a gentle relief on supports; b - top view of a fragment of the workpiece; c is a section of a workpiece fragment with a plane perpendicular to zigzag lines; g - size calculation scheme.

The filler structure is characterized by zigzag lines of protrusions 1, zigzag lines of depressions 2, segments of 3 sawtooth lines along which protrusions form, and segments of 4 sawtooth lines by which depressions form, and side faces 5. The filler has a folded structure, i.e. It is developed on the plane without gaps and imposition of material. The lines typical for the filler in the scan are indicated by the same numbers. The markup on the scan is set by the parameters S ₀ , L ₀ , V ₀ (figa), where S ₀ is the step between the sawtooth lines; L ₀ is the step between the zigzag lines; V ₀ - the amplitude of the zigzag lines on the markup.

In sections A-A, B-B, C-C, D-D (Fig.2b), grooves 6 and 7 are visible on the corresponding side of the workpiece. On the enlarged fragments of the workpiece I (from the upper) and II (from the lower) side, recesses 8 and 9 are visible at the intersection of the zigzag and sawtooth lines (Fig.2c).

The pattern of forming a gentle relief is shown in Fig. 5a. On figb shows a top view of the workpiece, which shows the direction of the minimum Oα and maximum Oβ deformations during shaping. Fig. 5c shows a cross section of the workpiece in which the greatest deformations take place. The relationship between the depth of the relief H, the length of the fiber q experiencing the maximum elongation, and the length of the same fiber in the deformed state Q is visible from the figure. Figure 5g shows a diagram allowing to establish the relationship between the length of the fiber q and the technological parameters of the marking.

The method is implemented as follows.

At the first stage, grooves are formed on a flat solid blank (Fig. 2): along the zigzag lines of the protrusions 1, which determine the position of the protrusions of the structure, and along the segments of the sawtooth lines 3, defining the protrusions along these lines in the structure, from one (for example, lower) side of the blank and along the zigzag lines of the depressions 2, determining the position of the depressions of the structure, and along the segments of the sawtooth lines 4, determining the depressions of these structure lines, on the other (respectively, upper) side of the workpiece. The formed grooves 6 and 7 weaken the bending stiffness of the material and provide accurate positioning of the deformation zones along the bending lines, minimizing the influence of tuning errors of the equipment forming the Z-shaped corrugation. In addition, clearly defined ribs with small rounding radii are formed along the bending lines themselves. All this leads to an increase in the accuracy of the aggregate structure.

The formation of grooves can be carried out using stamps on the press or in a rotational manner using rolls with ribs providing a given marking pattern.

The effect of weakening the stiffness of the workpiece (inflection lines on the marking) can be enhanced if, in all nodes of the intersection of lines on the marking, grooves are made (position in Figs. 2a, 2c), and if the node is located on a zigzag line of protrusions, then the groove is performed from the bottom side, and if the node lies on a zigzag line of depressions, then on the upper side of the workpiece.

The weakening of the stiffness of the workpiece along the bend lines can be carried out by punching holes of small diameter along all the marking lines (Figure 4). This can be accomplished in a known manner, for example, by stamping, laser beam processing or electrochemical processing, and such a weakening of rigidity is carried out on one side of the workpiece, which simplifies the process of obtaining weakening of the workpiece along the inflection lines.

At the second stage, a zigzag corrugated structure is formed from a workpiece with grooves or holes made on it. In this case, bending lines are formed along the grooves or at the places of punching holes that determine the position of the zigzag and sawtooth lines of the structure. As a result, we obtain a three-dimensional structure of a folded-type aggregate — FIG. 1.

The formation of the aggregate from the workpiece with grooves or with punched holes along the marking lines can be carried out using the corrugating devices proposed in the literature [1] and [3].

The formation of a Z-shaped corrugation from blanks with grooves can be realized on simpler equipment, if after grooving, a flat relief with the structure of a Z-shaped corrugation is formed at the blank. Then the necessary zigzag corrugated structure can be obtained by squeezing the workpiece with a gentle relief to the product with a given density of relief (Fig.3-3v):

A gentle relief can be obtained by one of the known sheet metal stamping methods with material drawing, for example by introducing punches along bending lines, as shown in FIG. 5a. The maximum depth of the shallow relief Н _max depends on the marking parameters and is limited by the plastic properties of the workpiece material, which are determined for sheet materials by δ _p - the maximum allowable uniform elongation (Romanovsky V.P. Cold stamping guide. - 6th ed., Revised and add. - L.: Engineering. Leningrad Branch, 1979, 520 p.) - [5].

Let us determine the relationship between the current relief depth H, the maximum deformation in the workpiece material and the marking parameters 2S ₀ , 2L ₀ , V ₀ .

At the first stage, we find on the faces of the workpiece the directions along which the material experiences maximum elongations, i.e. there are major deformations (Feodosiev V.I. Resistance to materials. Textbook for technical colleges. - M .: Nauka. Gl. Ed. Phys.-Math. Lit. 1986. - 512 p.) - [6].

We introduce an auxiliary coordinate system αOβ, in which the axis Oα coincides with the segment of the zigzag line of the depressions CD (Fig.5b). The deformations in the Oα direction are denoted by εα, and in the direction of the Oβ axis, by εβ.

The process of deformation of the workpiece in order to give a gentle zigzag corrugated structure is characterized by the following features:

- due to the regularity of the structure, all its faces are in the same conditions of deformation, therefore, it suffices to consider one of them, for example, ABCD (Fig.5b);

- a segment of a zigzag line of depressions CD during deformation moves plane-parallel in a vertical plane, always remaining parallel to the segment AB;

- all points lying on the segments AD and BC move in vertical parallel planes along vertical lines.

As a result, we can conclude that the fibers of the material located parallel to the ribs AB and DC do not experience elongation, i.e. the strain in this direction is εα = 0.

As a result, from the theory of principal stresses and principal strains [6], the strains εβ in the direction of Oβ will be maximum (principal). So, they will be the criterion for limiting the relief depth H _max .

Consider the face ABCD in the section KK, perpendicular to the axis Oα (Fig.5g).

The length Q of the deformed fiber can be determined through its initial length q and deformation in this direction εβ by the formula

Q = q (1 + εβ). (1)

Then, by the Pythagorean theorem, one can find the relief depth H:

Express q through the markup parameters 2S ₀ , 2L ₀ , V ₀ .

Consider a parallelogram ABCD (Fig.5g). Draw perpendicular AF from point A to side BC and perpendicular CE from point C to side AB. The resulting triangles CBE and ABF are similar in equality of two angles.

From the similarity of triangles it follows that

We find the value of AB from ΔABF by the Pythagorean theorem:

Substituting (4) into (3), we obtain

We substitute (5) into expression (2), we obtain the formula

To determine the maximum allowable relief height H _max, we replace in the formula (6) the strain εβ with the maximum allowable uniform elongation δ _p :

On the right side of formula (7), the maximum permissible uniform elongation δ _p is found in accordance with GOST 11701-84 “Tensile test methods for thin sheets and ribbons” [7] or can be found in reference books on cold stamping, for example [5]. Values S ₀ , L ₀ , V ₀ are set as marking parameters.

As a result, formula (7) allows you to determine the maximum allowable relief depth H _max , which can be given to the workpiece before its final shaping.

Thus, a method is proposed that makes it possible to obtain aggregate with a zigzag corrugated structure with high accuracy from solid sheet materials, and it can be implemented using known technologies, equipment and materials.

Used sources

1. RF patent No. 2118217, MKI B 21 D 13/00, Device for corrugating sheet material, V. I. Khaliulin, I. V. Dvoeglazov, publ. Bull. No. 24 dated 08/27/1998.

2. RF patent No. 1706148, MKI B 32 V 15/00, 29 C 59/00, Device for manufacturing products of complex profile from composite material, V.I. Khaliulin, V.E. Desyatov, publ. Bull. No. 16 dated 06/12/1996.

3. RF patent No. 2100120, MKI B 21 D 13/00, 13/02, A method of manufacturing a zigzag corrugation (options) and a device for its implementation, V.I. Khaliulin, E. A. Skripkin, publ. Bull. No. 36 dated 12/27/1997.

4. RF patent No. 2057647, MKI B 29 D 9/00, Method for manufacturing aggregate from composite material, V.I., Khaliulin, V.E. Tens, publ. Bull. No. 10 dated 04/10/1996.

5. Romanovsky V.P. Handbook of cold stamping. - 6th ed., Revised. and additional - L .: Mechanical engineering. Leningrad branch, 1979, 520 p.

6. Feodosiev V.I. Strength of materials. Textbook for technical colleges. - M .: Science. Ch. ed. Phys.-Math. lit., 1986 .-- 512 s.

7. GOST 11701-84 “Tensile test methods for thin sheets and tapes” was put into effect by the State Committee. USSR according to the standards of 07.17.84 No. 2514.

Claims (5)

1. A method of manufacturing a filler with a zigzag corrugated structure for a multilayer panel, including local weakening of the stiffness of the workpiece along the marking lines in the zones of the proposed bending and shaping the workpiece according to the shape of the cells of the zigzag structure, characterized in that the local weakening of rigidity on the hard workpiece is formed by forming zigzag grooves protrusions that determine the position of the protrusions of the structure, and along the segments of the sawtooth lines that define the protrusions along these lines in the structure, on the one hand of the workpiece and along the zigzag lines of the depressions that determine the position of the depressions of the structure, and along the segments of the sawtooth lines that define the depressions along these lines in the structure, on the other side of the workpiece. 2. The method according to claim 1, characterized in that the recesses are formed in all intersection nodes on the marking of the workpiece of zigzag lines of protrusions and zigzag lines of depressions with sawtooth lines on the corresponding side. 3. The method according to claim 1 or 2, characterized in that after the formation of the grooves and recesses, the workpiece is given a gentle relief according to a given zigzag corrugated structure, while the maximum allowable relief depth H _max is determined by the formula

where H _max - the maximum allowable depth of the relief, S ₀ is the step between the sawtooth lines; L ₀ is the step between the zigzag lines; V _{0 is the} amplitude of the zigzag lines on the markup; δ _p - the maximum allowable uniform elongation. 4. The method according to claim 1 or 3, characterized in that the formation of a zigzag corrugated structure is carried out by squeezing the workpiece with the obtained flat relief to the structure with a given density of relief.  5. A method of manufacturing a filler with a zigzag corrugated structure for a multilayer panel, including local weakening of the stiffness of the workpiece along the marking lines in the areas of the proposed bending and shaping the workpiece according to the shape of the cells of the zigzag structure, characterized in that the local weakening of rigidity on the hard workpiece is carried out by punching holes of small diameter along zigzag lines of protrusions, zigzag lines of hollows and saw-like lines of a given zigzag corrugated th structure on one side of the workpiece.

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