RU2381955C2 - Panel of curvilinear shape and method of its manufacturing - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: panel of curvilinear shape comprises upper and lower linings and zigzag corrugated filler arranged in between. Filler is arranged in the form of folded construction of helical structure, which, in its finally transformed condition contains cells along each serrated line, which are limited with inclined and vertical walls produced by two pairs of adjacent facets in the form of irregular quadrangles separated with section of zigzag line inclined towards serrated line, which is common for both pairs, at the angles of α₁ and α₂. α₁ is angle between common serrated line and section of zigzag line, which separates a pair of adjacent facets, which, in finally transformed condition produce vertical wall of cell. α₂ is angle between common serrated line and section of zigzag line, which separates a pair of adjacent facets, which, in finally transformed condition produce inclined walls of cell, at the same time condition of α₁<α₂ is maintained. According to method for manufacturing of multilayer panel of curvilinear shape with separate shaping of linings with specified curvature and layer of filler, sheet stock at the first stage is marked with bending lines, which produce elementary modules with specified geometric parametres. At the second stage sheet stock is transformed into relief position, where it takes form of folded construction of helical structure. At the third stage produced folded construction is shaped till finally transformed condition, which is characterised by formation of cells limited with inclined and vertical walls.

EFFECT: increased strength and rigidity of panels.

2 cl, 13 dwg, 1 tbl

Description

The invention relates to the production of panels and shells with lightweight aggregates and can be used in the manufacture of multilayer panels in aircraft, shipbuilding, construction and other industries.

A known design of a multilayer panel in which corrugated filler has increased contact areas between the skin and the filler due to triangular grooves made along the lines of protrusions and depressions (USSR Author's Certificate No. 1646196, MKI B64C 3/26. Multilayer panel. - Publ. 21.08. 91. Bull. No. 31).

The disadvantage of this aggregate design is the use of additional composite material filling the grooves, which complicates the manufacturing and assembly process, leads to an increase in the specific mass characteristics of the multilayer panel. In addition, with a good connection of the filler with the casing, this design, when subjected to compressive and tensile forces on the panel, does not have satisfactory strength characteristics in comparison with, for example, honeycomb fillers in which the faces are perpendicular to the casing.

As a prototype, a well-known multilayer panel was selected in which the corrugated aggregate has increased contact areas between the skin and the core due to the fact that the contact areas of the core and the lower skin are curved in the form of lenticular elements located at the depressions of the side faces of the core and the contact area the filler with the upper skin is also made curved in the form of a composite material located between the side faces of the filler at its vertices (Pat t RU №20382653, V64S 3/26 sandwich panel -.. Publ 27/06/95)..

The disadvantage of this aggregate design is the difficulty in manufacturing the enlarged contact areas made curved in the form of lenticular elements.

A known method of manufacturing a multilayer panel, in which an increase in the strength and rigidity of the panel is achieved due to the fact that the honeycomb core is made of strips of material specified by the calculation of the width and adjacent strips of the bulky filler are articulated to each other with an equal pitch in their lower zone. Then, the outer and inner skins are glued to the bulky filler (Copyright Certificate SU No. 1078007, MKI B32B 3/12. Three-layer panel. - Publish. 07.03.84. Bull. No. 9).

The disadvantage of this method lies in the complexity of manufacturing the articulated connector and its subsequent connection to the filler strips.

The closest in technical essence is a method of manufacturing a multilayer panel, in which an increase in the strength and rigidity of the panel is achieved due to the fact that the filler is made in the form of two layers of a zigzag corrugation, while the main corrugated layer is connected to the upper and lower casing, and the additional corrugated layer is with top lining and main corrugated layer. The device implemented by this method is taken as a prototype (USSR Author's Certificate No. 1830326, MKI V23K 20/00. A method for manufacturing a multilayer curved-shaped panel with a zigzag corrugated filler. - Publish. 30.07.93. Bull. No. 28).

The disadvantage of this method is that the use of two layers of filler with different geometric parameters increases the weight of the panel and requires the manufacture of different hardware designs, which increases the material consumption and the complexity of manufacturing.

The purpose of the invention is to increase the strength and stiffness of a curvilinear panel containing plating and filler based on a zigzag corrugation by organizing cells with vertical walls as a part of the filler.

The goal is achieved by the fact that in the known panel containing the upper and lower sheathing and placed between them a zigzag corrugated filler, unfolding on a plane, with side faces at an angle to one another with the formation of alternating protrusions and depressions, according to the proposed technical solution, the filler is made in in the form of a folded design of a spiral structure containing, in its finite-transformed state, along each sawtooth line of the cell, limited by inclined and vertically -trivial walls defined by two pairs of adjacent faces in the form of irregular quadrilaterals split segment zigzag line inclined to the sawtooth line common to both pairs, at an angle α _1, and the sloping walls of the cell are formed by a pair of adjacent faces separated by a segment of the zigzag line, tilted to the same the sawtooth line at an angle α ₂ , while the condition α ₁ <α ₂ .

According to the method of manufacturing a multilayer panel of a curvilinear shape, the goal is achieved by the fact that in the known method, comprising separately shaping the outer skin of a given curvature and a filler layer obtained by bending the sheet blank according to the zigzag lines of the protrusions and troughs outlined according to the invention, the sheet blank at the first stage , mark over the entire area by repeating the same shape, size and orientation of the elementary units with the geometric parameters a _0, a _1, b _0, b _1, β _0, β _{1, 2.} At the second stage, the sheet blank is transformed into a relief position in which it takes the form of a structure distributed along a helical line. At the third stage, the resulting folded structure is formed to a finite-transformed state characterized by the formation of cells bounded by inclined and vertical walls. The finite-transformed state of the folded structure is determined by the value of the angle α _before .

The analysis of the prior art cited by the applicant made it possible to establish that there are no analogs characterized by sets of features identical to all the features of the claimed technical solution. Therefore, the claimed technical solution meets the condition of patentability "novelty."

The search results for known solutions in the art in order to identify features that match the distinctive features of the prototype of the features of the claimed technical solution have shown that they do not follow explicitly from the prior art. From the prior art determined by the applicant, the influence of the transformations provided for by the essential features of the claimed technical solution on the achievement of the specified technical result is not known. Therefore, the claimed technical solution meets the condition of patentability "inventive step".

The invention is illustrated by drawings, where figure 1 shows a side view of a folded filler in its intermediate position. Figure 2 shows the same folded placeholder in a finite-transformed state. Figure 3 shows a section aa of the folded filler of figure 1. The arrows show the direction of movement of the filler faces in the process of compression. Figure 4 shows a section bB of the folded aggregate of figure 2.

In a finite-transformed state, two pairs of faces adjacent along a sawtooth line form a cell bounded by inclined and vertical walls. These walls are formed by two pairs of adjacent faces in the form of irregular quadrangles separated by a segment of a zigzag line inclined to a sawtooth line common to both pairs at an angle α ₁ , and the inclined cell walls are formed by a pair of adjacent faces separated by a segment of a zigzag line inclined to the same sawtooth line at an angle α ₂ , while the condition α ₁ <α ₂ .

The proposed aggregate is made in a new way. The essence of the new method is illustrated by drawings, where Fig. 5 shows an elementary module of a folded structure in a flat state (on a scan). Figure 6 shows the elementary module of the folded structure in a relief state formed by the rotation of the ribs connecting the nodal zones (nodes) 1-0 and 0-5, around the nodal zone 0 in the plane YgOZg. The position and orientation of the axes Xg, Yg, and Zg of the corrugation coordinate system (SCr) are also shown. Figure 7 shows two directions of the distribution of the structure: direction 1 is rectilinear, direction 2 is along the helix. On Fig shows the placement and orientation of the axes Xc, Yc and Zc of the helix coordinate system (SCC) Xc0Yc. Figure 9 explains the procedure for determining the position of the axis of the helix. Figure 10 explains the procedure for determining the pitch of the helix. 11 illustrates the process of organizing a continuous folded cylindrical surface from a spiral folded structure. On Fig shows a fragment of a spiral-shaped folded structure, compressed to a finite-transformed state and containing cells bounded by vertical and inclined walls. On Fig shows a continuous folded cylindrical surface with vertical walls, obtained on the basis of a spiral folded structure, compressed to a finite-transformed state.

5-13, the numbers denote: 1 - sawtooth lines, 2 - zigzag lines, 3 - axis of the helix, 4 - vertical cell walls, 5 - inclined cell walls.

The inventive method is implemented as follows.

At the first stage, the sheet blank is marked with zigzag and sawtooth lines along the length and width so that the shape of the obtained repeating octagons matches the scan shape of the elementary module shown in Fig. 5.

At the second stage, the sheet blank is transformed by known methods into a relief position so that the edges connecting the knot (s) .1-knot.0 and knot.0-knot 5 of each elementary module rotate around knot 0 in a vertical plane passing through Uz. 1 and Uz. 5. Such a transformation entails a change in the position of the remaining nodal zones, which receive increments in all three coordinates and form a three-dimensional structure (Fig.6). The angle between the edges of knots 1-knot 0 and knot 0-knot 5, which characterizes the density of the relief and the overall dimensions of the folded structure, is called the angle of transformation α.

To describe the shape of the folded structure in a relief position, we single out two directions along which we will consider the distribution of its elementary module — the direction along the zigzag lines and the direction along the sawtooth lines. We also introduce a corrugation coordinate system (SKg) such that the beginning of SKg coincides with knot 0, while the Zg axis divides the angle α in half, the Yg axis lies in the plane of knots 0-knots 1-knots 5, and the Xg axis forms the right rectangular cartesian coordinate system.

An analysis of the behavior of the nodal zones of the elementary module in the embossed position shows that the distribution of the structure in the directions of zigzag and sawtooth lines is carried out according to various laws.

In the direction of the zigzag line, the elementary modules propagate parallel to the lines connecting nodes 8-nodes 2 and 6-nodes 4 (direction 1 in Fig. 7). The difference between the angles β ₀ and β ₂ (Fig. 5) leads to the appearance of a difference in the coordinate Yg between Uz.2 and Uz.8, Uz.3 and Uz.7, Uz.4 and Uz.6, in a relief position, and , as a consequence, to a distortion of the shape of the elementary module in the XGOYg plane (factor 1).

In the direction of the zigzag line, elementary modules propagate according to the law determined by the difference in the coordinate Zг between the nodal zones 4, 5, 6 (group 1) and the nodal zones 2, 1, 8 (group 1), as well as between the nodal zones, which are pairwise different groups. This difference is due to the difference in the angles β ₀ , β ₁ and leads to the fact that the structure receives curvature in the longitudinal plane (factor 2).

The combined action of factor 1 (distortion of the shape in the plan) and factor 2 (the occurrence of curvature in the Yy0Zy plane) leads to the fact that each module following the sawtooth line receives a rotation simultaneously around the Zy axis and the Yy axis with respect to the previous module. As a result, the structure along the sawtooth line is spread over a three-dimensional curve described by the helix equation.

At the third stage, the folded structure is formed to a finite-transformed state, characterized by the formation of cells bounded by inclined and vertical walls (5 and 4 in FIG. 12, respectively). These walls are formed by two pairs of adjacent faces separated by segments of a zigzag line, each of which is inclined to a common sawtooth line at angles α ₁ and α ₂ so that the condition

α ₁ <α ₂ . Here, α ₁ is the angle between the common sawtooth line and the segment of the zigzag line dividing a pair of adjacent faces forming a vertical cell wall in a finite-transformed state, α ₂ is the angle between the common sawtooth line and the segment of the zigzag line dividing a pair of adjacent faces forming in the finite -transformed state of the inclined cell wall. In Fig. 5, the faces formed by the nodal zones 1-2-3-0 and 3-4-5-0 in a finite-transformed state form a vertical wall, and the faces 1-0-7-8 and 0-5-6-7 form inclined cell walls, as angle β ₂ <β ₀ .

The geometric dimensions of the multilayer curved panel are determined by the geometric parameters of the folded filler contained in it. Relations are known for obtaining the geometric parameters of the folded structure of a single curvature (propagated along a sawtooth line along a flat arc), but they are not suitable for determining the geometric parameters of the structure propagated along a helix.

The following is a conclusion of the relationships allowing us to establish the relationships between the specified technological parameters of the filler distributed along the helical line and the desired structural parameters of the multilayer curved panel in the embossed position.

We will perform the derivation of dependencies in stages. At the first stage, we introduce the design and technological parameters of the multilayer curvilinear panel and establish the dependencies connecting the coordinates of the nodal zones of the elementary module in the embossed position (for some given transformation angle α) with the given geometric parameters a ₀ , a ₁ , b ₀ , b ₁ , β ₀ , β ₁ , β _{2 of the} elementary module on the scan. At the second stage, we determine the design parameters of the folded filler distributed along a helical line. At the third stage, we establish the dependences characterizing the folded structure, compressed to a finite-transformed state and forming a continuous cylindrical surface.

First step.

The design parameters of the multilayer curved panel are:

h ₁ , h ₂ - the thickness of the outer and inner casings, respectively;

R ₁ is the radius of curvature of the surface covered by the folded filler (Fig.7);

R ₂ is the radius of curvature of the surface covering the folded aggregate (Fig.7);

t is the pitch of the helix along which the folded filler extends;

X _Ti , Y _Ti , Z _Ti (i = 1 ... 8) - the coordinates of the nodal zones of the elementary module of the corrugation in the current embossed position (Fig.6).

The technological parameters of the multilayer curved panel are:

and ₀ , a ₁ , b ₀ , b ₁ , β ₀ , β ₁ , β ₂ are the geometric parameters of the elementary module of the folded filler on the scan (figure 5);

α is the angle of transformation of the folded filler (Fig.6).

The thicknesses of the outer (h ₁ ) and inner (h ₂ ) claddings are set based on the operating conditions of the structure and technological features of the panel production.

The coordinates of the nodal zones of the elementary module of the corrugation in the current embossed position X _Ti , Y _Ti , Z _Ti (i = 1 ... 8) are determined by the known dependencies in the form

X _Ti , Y _Ti , Z _Ti = f (X _Pi , Y _Pi , Z _Pi , α) (i = 1 ... 8),

where X _Pi , Y _Pi , Z _Pi (i = 1 ... 8) are the coordinates of the nodal points of the elementary module of the folded filler on the scan, which are associated with the geometric parameters a ₀ , a ₁ , b ₀ , b ₁ , β ₀ , β ₁ , β ₂ dependencies are shown in table 1.

Table 1 Coord. Point Numbers one 2 3 four 5 6 7 8 Hr 0 -b ₂ sinβ ₂ -b ₂ sinβ ₂ -b ₂ sinβ ₂ 0 b ₁ sinβ ₀ b ₁ sinβ ₀ b ₁ sinβ ₀ Yp -a ₀ b ₂ cosβ ₂ -a ₀

a ₁ + b ₂ cosβ ₀ a ₁ a ₁ + b ₁ cosβ ₀

b ₁ cosβ ₀ -a ₀

Second phase.

The determination of the radii of curvature of the covering and covered surfaces, as well as the step of the helix, we perform in the following sequence.

We introduce a spiral coordinate system (SKS) such that the origin of SKS coincides with knot 0 (the origin of coordinates of SKg and SKs coincide), the Zc axis is parallel to the line of knots 2-knots 8, the Xc axis is parallel to the plane passing through the nodal zones 2-4 -8, the Yc axis forms the right rectangular Cartesian coordinate system (Fig. 8).

To recalculate the coordinates X _Ti , Y _Ti , Z _Ti (i = 1 ... 8) of the nodal zones in the new SCS, we define the direction cosines of the axes X _c , Y _c , Z _c relative to the axes X _g , Y _g , Z _g in such a way that

- the axis X _C will have guide cosines s ₁₁ , s ₁₂ , S ₁₃ relative to the axes X _g , Y _g , Z _g, respectively;

- the axis Y _C will have guide cosines s ₂₁ , s ₂₂ , s ₂₃ relative to the axes X _G , Y _G , Z _G, respectively;

- the axis Z _C will have guide cosines s ₃₁ , s ₃₂ , s ₃₃ relative to the axes X _G , Y _G , Z _G, respectively.

Using the known dependencies of analytic geometry, we determine the direction cosines s _ij (i = 1 ... 3, j = 1 ... 3) as follows

- directional cosines of the X axis _with respect to the X _g , Y _g , Z _g axes of the corrugation coordinate system (SCr), respectively;

- guide cosines of the axis Y _C relative to the axes X _G , Y _G , Z _G SKg, respectively;

- guide cosines of the Z axis _with respect to the X _g , Y _g , Z _g SKg axes, respectively. Moreover

Recalculation of coordinates of points from SKg to SKS is performed according to the following dependencies

To determine the position and orientation of the axis of the helix forming cylinder, it must be borne in mind that the axis of the helix is directed toward the displacement of the elementary module, i.e. parallel to the line passing through Uz.2-Uz.8, and the plane of the base of the forming cylinder of the helical line is oriented perpendicular to the line Uz.2-Uz.8.

We construct the base plane of the generatrix of the cylinder parallel to XcOYc and passing through knot 8 (shaded in figure 9). We project the nodal zones 1, 5, 6 on the plane of the base and build lines 1 _PR -5 _PR and 6 _PR -8 _PR (Fig. 9). Intersection point

0 _{From the} normals restored to the midpoints of lines 1 _OL- 5 _OL and 6 _OL -8 _OL , is the point at which the axis of the helical line intersects the plane of the base of the forming cylinder.

After performing the known transformations of analytic geometry, the coordinates of t.0 _{C are} written in the following form

Таким образом, радиус кривизны поверхности, охватываемой складчатым заполнителем, определим как расстояние от т.0_С до середины линии

Thus, the radius of curvature of the surface covered by the folded filler is defined as the distance from t.0 _C to the middle of the line

and the radius of curvature of the surface covering the folded filler - as the distance between the projection of knot 0 on the plane of the base of the spiral and t 0 _C

To determine the pitch of the helix t, we consider a helix passing through knot 8 and knot 6. The projection of this helix on the plane of the base of the forming cylinder will be an arc with a certain radius R _k (Fig. 10).

The pitch of the helix t is determined from the relation

t = πD _K tgα _П ,

where α _P is the angle of elevation of the helix, which we find as

Here Δ _Z = Z _C8 -Z _C6 is the difference in the Zc coordinate between knots 8 and knots 6;

D _K = 2R _K ;

(фиг.10), который найдем из соотношенияφ, rad - the angle between the lines 0 _C -8 _PR and 0 _C -6 _PR , which determines the length of the arc

(Fig. 10), which we find from the relation

We write the final formula for determining the helix pitch

The third stage.

A folded filler, compressed to a finite-transformed state and forming a continuous cylindrical surface, characterizes the limiting angle of transformation α _before and the dependence setting such a number of elementary modules distributed in direction 1 (Fig. 7), which is placed an integer number of times between the turns of a helix.

The limiting angle of transformation α _before is the angle characterized by the angle of inclination of the segment of the zigzag line emanating from node 0 of the elementary module (figure 5). Because two segments of a zigzag line come out from knot 0 (knot 0-knot 3 and knot 0-knot 7), belonging to two halves of the elementary module, separated by a sawtooth line of knot 1-knot 5, then you need to consider that half of the elementary a module whose faces close earlier. An analysis of the dynamics of the movement of groups of nodes 2, 3, 4, and 6, 7, 8 shows that the faces of that half of the elementary module whose angle β ₀ or β _{2 are} smaller are previously closed.

Thus, based on the given geometric parameters b ₀ , b ₁ , β ₀ , β ₁ , β _{2 of the} elementary module on the scan, we find the angle α _before using the following formula

provided that β ₂ <β ₀ or according to the formula α _pre = 2 (90-β ₁ ) provided β ₂ > β ₀ .

In order for elementary modules located in adjacent turns to join along a sawtooth line during the transformation, it is necessary that the distance of knots 2-knots 8 fit an integer number of times per step of the helix. We write this condition in the form

where k is a positive integer

- расстояние между уз.2 и уз.8.

- distance between knot 2 and knot 8.

The proposed technical solutions for the design of a multilayer curved panel and the method of its manufacture can be used in the industrial production of fuselage panels of passenger aircraft. The technology created on the basis of this method will reduce the cost of industrial production of multilayer fuselage panels of passenger aircraft.

Claims (2)

1. The panel is curved in shape, containing the upper and lower casing and placed between them zigzag corrugated filler, deployed on a plane, with side faces at an angle to one another with the formation of alternating protrusions and depressions, characterized in that the filler is made in the form of a folded structure spiral structure, containing in its finite-transformed state along each sawtooth line of the cell, limited by inclined and vertical walls formed by two pairs of adjacent faces in the form of irregular quadrangles separated by a segment of a zigzag line inclined to a sawtooth line common to both pairs at angles α ₁ and α ₂ , where α ₁ is the angle between a common sawtooth line and a segment of a zigzag line separating a pair of adjacent faces, forming a finite-state vertical wall transformed cells, α ₂ - the angle between the common line and the segment sawtooth zigzag line which separates the pair of adjacent edges, forming a finite-state slope of the transformed s cell wall, wherein the condition α ₁ <α _2. 2. A method of manufacturing a multilayer panel of a curvilinear shape with separate shaping of the skin of a given curvature and a filler layer obtained by bending the sheet stock according to the zigzag lines of protrusions and depressions marked on the scan, characterized in that the sheet stock:
mark with bending lines forming elementary modules with geometric parameters:
a ₀ - the smallest distance between the vertices of adjacent zigzag lines of protrusions and troughs,
a ₁ - the largest distance between the vertices of adjacent zigzag lines of protrusions and troughs,
b ₀ - the length of the segment of the zigzag line of the troughs of the elementary module,
b ₁ - the length of a smaller segment of the zigzag line of the troughs of the elementary module,
β ₀ is the angle between α ₀ and b ₀ ,
β ₁ is the angle between a ₀ and a large segment of the zigzag line of protrusions of the elementary module,
β ₂ is the angle between a ₀ and b ₁ ;
transform into a relief position in which it takes the form of a folded structure of a spiral structure with structural parameters:
R ₁ is the radius of curvature of the surface enveloping the folded core from the inside,
R ₂ is the radius of curvature of the surface enveloping the folded filler outside,
t is the pitch of the helix,
defined by formulas

,

,

,

and

coordinates determining the position of the axis of the helix in the spiral coordinate system (SCS);

,

and

,

- coordinates of the midpoints of the projection of the segments used in determining the position of the axis of the helix in the SCS;
X _Ci , Y _Ci , z _Ci , (i = 1 ... 8) - the coordinates of the nodal zones of the elementary module of the structure in the SCS, which are determined from the dependencies

,
in which

,

,

guide cosines of the X axis _with respect to the X _g , Y _g , Z _g axis of the corrugation coordinate system (SK _g ), respectively,

,

,

- guide cosines of the axis Y _With respect to the axes X _G , Y _G , Z _G SKG, respectively, and

,

,

;

,

,

- guide cosines of the axis
Z _C relative to the axes X _G , Y _G , Z _G SKg, respectively, and
X _Ti , Y _Ti , Z _Ti (i = 1 ... 8) - the coordinates of the nodal zones of the elementary module of the structure in the elevated position in SKg, which are determined from the known dependencies;
- the resulting folded structure is shaped to a finite-transformed state, determined by the angle between the segments of the sawtooth line α _before , which is calculated by the formula

provided that
β ₂ <β ₀ or according to the formula α _pre = 2 (90-β ₁ ) under the condition β ₂ > β ₀ , and thus form a spiral structure containing cells bounded by inclined and vertical walls consisting of two pairs of adjacent faces in the form of irregular quadrangles separated by segments of zigzag lines, each of which is inclined to a common sawtooth line at angles α ₁ and α ₂ so that the condition α ₁ <α ₂ is fulfilled, where α ₁ is the angle between the common sawtooth line and the segment of the zigzag line separating a pair of adjacent faces forming a horse but-transformed state of the cell wall of the vertical, α ₂ - the angle between the common line and the segment sawtooth zigzag line separating the pair of adjacent edges, forming a finite-state inclined transformed cell wall.

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