CN113673043A - Unfolding method of variable-thickness skin based on unfolding layer - Google Patents
Unfolding method of variable-thickness skin based on unfolding layer Download PDFInfo
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- CN113673043A CN113673043A CN202010400957.0A CN202010400957A CN113673043A CN 113673043 A CN113673043 A CN 113673043A CN 202010400957 A CN202010400957 A CN 202010400957A CN 113673043 A CN113673043 A CN 113673043A
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 239000000463 material Substances 0.000 claims description 10
- 238000009826 distribution Methods 0.000 claims description 5
- 238000013000 roll bending Methods 0.000 claims description 3
- 238000007493 shaping process Methods 0.000 claims description 3
- 208000020312 Thickened skin Diseases 0.000 claims 3
- 239000002184 metal Substances 0.000 description 9
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 108700041286 delta Proteins 0.000 description 1
- 238000004836 empirical method Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/17—Mechanical parametric or variational design
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
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Abstract
The invention relates to the technical field of aircraft skin unfolding, and discloses a unfolding method of a variable-thickness skin based on an unfolding layer, which comprises the steps of calculating unfolding size deviations of different areas and different unfolding layer positions of a part to obtain the unfolding layer position with the minimum overall error, and unfolding the part by taking the unfolding layer position as an actual unfolding layer; wherein the developing size deviation delta l, delta l ═ delta l1+△l2，△l1For geometric development of dimensional deviation,. DELTA.l2Is the amount of extension. And calculating the expansion size deviation of different areas and different expansion layer positions of the part to obtain an expansion layer position with the minimum overall error, and taking the position as an actual expansion layer to expand the part. The method can realize the expansion of the variable-thickness skin, and the expansion error is smaller than that of the geometric method; in addition, the method can be used for unfolding complex parts which cannot be accurately unfolded even finite element software such as FTI (flash translation interface), Dynaform and the like is unfolded; furthermore, the method is simple,the requirement on the level of operators is not high.
Description
Technical Field
The invention relates to the technical field of aircraft skin unfolding, in particular to a unfolding method of a variable-thickness skin based on an unfolding layer.
Background
Sheet metal machining is an important component in mechanical production, and sheet metal parts are widely applied to the industries of aerospace, ship manufacturing, automobiles and the like. Taking the aviation industry as an example, a sheet metal part as an important component of a modern aircraft body generally accounts for more than 30% of the total number of parts of the whole aircraft, and because the sheet metal part has the characteristics of complex structure, high precision requirement, multiple varieties, small batch and the like, the manufacturing time of the part usually accounts for 15% of the total time of the whole aircraft, and therefore the manufacturing process of the sheet metal part directly affects the whole quality and the production cycle of the aircraft. In the manufacturing process of sheet metal parts, unfolding is an important process.
Typical parts such as skins, bulkheads, wing ribs and the like which are used in a large number in an airplane body have complex configurations, unequal thicknesses and uneven thickness distribution, so that the traditional unfolding technologies such as a geometric method, an analytical method, an empirical method and the like are difficult to adapt to the requirements of modern airplane development, professional finite element software such as FTI, Dynaform and the like cannot realize the unfolding of complex sheet metal parts, and universal finite element software such as ABAQUS, ANSYS and the like has higher requirements on part unfolding methods for process personnel.
Therefore, a development method which is simple to operate, high in precision and suitable for aviation sheet metal part production needs to be found, and a solid foundation is laid for realizing sheet metal digital manufacturing in the aviation field.
Disclosure of Invention
The invention aims to provide a variable-thickness skin unfolding method based on an unfolding layer, which can realize the unfolding of the variable-thickness skin, has small unfolding error, is simple and has low requirement on the level of an operator.
In order to achieve the purpose, the invention adopts the following technical scheme:
the unfolding method of the variable-thickness skin based on the unfolding layer is provided, the unfolding size deviation of different areas and different unfolding layer positions of a part is calculated, the unfolding layer position with the minimum overall error is obtained, and the position is used as an actual unfolding layer for unfolding the part;
wherein the developing size deviation delta l, delta l ═ delta l1+△l2，△l1For geometric development of dimensional deviation,. DELTA.l2Is the amount of extension.
As a preferable technical scheme of the unfolding method of the variable-thickness skin based on the unfolding layer, the selection of the position of the unfolding layer comprises the following steps:
s1, dividing the part into a plurality of areas along the width direction of the skin according to the thickness distribution;
s2, selecting a feature plane representing the area on each area;
s3, selecting a most spread representative thickness delta on each characteristic surfacep；
S4, selecting proper number of unfolding layer positions within the range of 0 < delta max/2.
As a preferable technical solution of the unfolding method of the variable thickness skin based on the unfolding layer, wherein,
delta is the thickness of the skin, R is the radius of the skin,
is the arc length of the inside face of the skin,
the arc length of the outer side of the skin.
As a preferred technical scheme of the unfolding method of the variable-thickness skin based on the unfolding layer, delta l2η × δ × l, η is the material elongation ratio, and l is the spanwise length of the skin blank.
As a preferable technical solution of the unfolding method of the variable thickness skin based on the unfolding layer, wherein,
selecting materials with equal thickness for roll bending, wherein the initial thickness of the blank is deltasThe outside of the part has an initial length of ls1After shaping to the desired curvature, the material length is measured as ls2。
The invention has the beneficial effects that:
and calculating the expansion size deviation of different areas and different expansion layer positions of the part to obtain an expansion layer position with the minimum overall error, and taking the position as an actual expansion layer to expand the part. The method can realize the expansion of the variable-thickness skin, and the expansion error is smaller than that of the geometric method; in addition, the method can be used for unfolding complex parts which cannot be accurately unfolded even finite element software such as FTI (flash translation interface), Dynaform and the like is unfolded; moreover, the method is simple and has low requirements on the level of operators.
Drawings
FIG. 1 is a schematic diagram of the digifax, geometric expansion and structure of the components provided by the present invention;
FIG. 2 is a schematic structural diagram of an AB unfolding layer provided by the present invention;
fig. 3 is a schematic structural diagram of the parts provided by the present invention.
In the figure: 1. a partition line; c. a digital model; d. geometrically unfolding; e. and (4) parts.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that are conventionally placed when the products of the present invention are used, and are used only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements to be referred to must have specific orientations, be constructed in specific orientations, and operate, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; either mechanically or electrically. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
The embodiment discloses a method for unfolding a variable-thickness skin based on an unfolding layer, which comprises the steps of calculating unfolding size deviations of different areas and different unfolding layer positions of a part to obtain the unfolding layer position with the minimum overall error as an actual unfolding layer, and unfolding the part by taking the position as the actual unfolding layer, as shown in fig. 1; wherein the developing size deviation delta l, delta l ═ delta l1+△l2，△l1For geometric development of dimensional deviation,. DELTA.l2Is the amount of extension.
The selection of the position of the unfolding layer comprises the following steps:
s1, dividing the part into a plurality of areas along the width direction of the skin according to the thickness distribution;
s2, selecting a feature plane representing the area on each area;
s3, selecting a most spread representative thickness delta on each characteristic surfacep；
S4, selecting proper number of unfolding layer positions within the range of 0 < delta max/2.
Then, the formula Δ l ═ Δ l is used1+Δl2The development size deviation deltal of each region is calculated separately,
specifically, AB is the unfolding layer, as shown in FIG. 2, A 'B' and A "B" are the features to be unfolded, and the difference between the two can be calculated by the following formula:
since the thickness δ of the skin is relatively small, the ratio can be approximated as δ/R. Thus, geometric expansion dimensional deviation
Delta is the thickness of the skin, R is the radius of the skin,
is the arc length of the inside face of the skin,
the arc length of the outer side of the skin.
Wherein the elongation Δ l2η × δ × l, η is the material elongation ratio, and l is the spanwise length of the skin blank.
The material elongation ratio is calculated by the following method,
selecting materials with equal thickness for roll bending, wherein the initial thickness of the blank is deltasThe outside of the part has an initial length of ls1After shaping to the desired curvature, the material length is measured as ls2。
The unfolding size deviations of different areas and different unfolding layer positions are integrated, and the unfolding layer position with the minimum overall error is found; and taking the position of the unfolding layer as an actual unfolding layer to unfold the part.
More specifically, the part is divided into several regions according to the thickness distribution, each region selecting a feature plane representing the region. For example, as shown in fig. 3, the part is divided into left and right regions A, B, and feature planes are selected respectively. The characteristic surface a has different thicknesses delta 1, delta 2 and delta 3; the feature plane b has different thicknesses δ 4, δ 5. And finding the maximum thickness delta max of the part, and selecting a proper number of unfolding layer positions within the range of 0 < delta max/2. At different unfolding layer positions, the unfolding size deviation deltal of the two areas is calculated respectively. And (4) integrating the unfolding size deviation of the different unfolding layer positions of the two areas, finding the unfolding layer position with the minimum error, and taking the unfolding layer position as an actual unfolding layer to unfold the part.
And calculating the expansion size deviation of different areas and different expansion layer positions of the part to obtain an expansion layer position with the minimum overall error, and taking the position as an actual expansion layer to expand the part. The method can realize the expansion of the variable-thickness skin, and the expansion error is smaller than that of the geometric method; in addition, the method can be used for unfolding complex parts which cannot be accurately unfolded even finite element software such as FTI (flash translation interface), Dynaform and the like is unfolded; moreover, the method is simple and has low requirements on the level of operators.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
Claims (5)
1. A unfolding method of a variable-thickness skin based on an unfolding layer is characterized in that unfolding size deviations of different areas and different unfolding layer positions of a part are calculated to obtain the unfolding layer position with the minimum overall error, and the position is used as an actual unfolding layer for unfolding the part;
wherein the developing size deviation delta l, delta l ═ delta l1+△l2，△l1For geometric development of dimensional deviation,. DELTA.l2Is the amount of extension.
2. The method for unfolding a thick-walled skin based on an unfolding layer according to claim 1, wherein the selection of the position of the unfolding layer comprises the following steps:
s1, dividing the part into a plurality of areas along the width direction of the skin according to the thickness distribution;
s2, selecting a feature plane representing the area on each area;
s3, selecting a most spread representative thickness delta on each characteristic surfacep；
S4, selecting proper number of unfolding layer positions within the range of 0 < delta max/2.
3. The method for spreading a thickened skin based on a spreading layer according to claim 2, wherein,
delta is the thickness of the skin, R is the radius of the skin,
is the arc length of the inside face of the skin,
the arc length of the outer side of the skin.
4. The method for unfolding a thickened skin based on unfolded layers according to claim 3, wherein Δ l2η × δ × l, η is the material elongation ratio, and l is the spanwise length of the skin blank.
5. The method for spreading a thickened skin based on a spreading layer according to claim 4, wherein,
selecting materials with equal thickness for roll bending, wherein the initial thickness of the blank is deltasThe outside of the part has an initial length of ls1After shaping to the desired curvature, the material length is measured as ls2。
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| CN202010400957.0A CN113673043B (en) | 2020-05-13 | 2020-05-13 | Unfolding method of variable-thickness skin based on unfolding layer |
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| CN202010400957.0A CN113673043B (en) | 2020-05-13 | 2020-05-13 | Unfolding method of variable-thickness skin based on unfolding layer |
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Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4912644A (en) * | 1986-12-02 | 1990-03-27 | Oki Electric Industry Co., Ltd. | Method of and apparatus for unfolding a sheet metal part employing a CAD apparatus |
| JP2007172057A (en) * | 2005-12-19 | 2007-07-05 | Murata Mach Ltd | System, method and program for processing sheet metal model, and data structure of object-oriented sheet metal model used by same |
| US20100042242A1 (en) * | 2004-12-17 | 2010-02-18 | Bae Systems Plc | Skin design process |
| US20100106463A1 (en) * | 2008-10-24 | 2010-04-29 | Autodesk, Inc. | Custom equations for the unfolding of sheet metal |
| CN102902851A (en) * | 2012-09-21 | 2013-01-30 | 西安飞机工业（集团）有限责任公司 | Unfolding modeling method for airplane integral panels based on computer-graphics aided three-dimensional interactive application (CATIA) |
| CN105653749A (en) * | 2014-11-14 | 2016-06-08 | 江西昌河航空工业有限公司 | Method for unfolding multi-honeycomb sandwich structure member upper skin paving layer |
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| EP3502930A1 (en) * | 2017-12-22 | 2019-06-26 | Dassault Systèmes | Method for computing an unfolded part of a modeled bended part of a 3d object |
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2020
- 2020-05-13 CN CN202010400957.0A patent/CN113673043B/en active Active
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| US20100042242A1 (en) * | 2004-12-17 | 2010-02-18 | Bae Systems Plc | Skin design process |
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| US20100106463A1 (en) * | 2008-10-24 | 2010-04-29 | Autodesk, Inc. | Custom equations for the unfolding of sheet metal |
| CN102902851A (en) * | 2012-09-21 | 2013-01-30 | 西安飞机工业（集团）有限责任公司 | Unfolding modeling method for airplane integral panels based on computer-graphics aided three-dimensional interactive application (CATIA) |
| CN105653749A (en) * | 2014-11-14 | 2016-06-08 | 江西昌河航空工业有限公司 | Method for unfolding multi-honeycomb sandwich structure member upper skin paving layer |
| EP3502930A1 (en) * | 2017-12-22 | 2019-06-26 | Dassault Systèmes | Method for computing an unfolded part of a modeled bended part of a 3d object |
| CN108555360A (en) * | 2018-06-27 | 2018-09-21 | 西安飞机工业（集团）有限责任公司 | Uniform thickness covering type part milling is not cut into neutral line method of deploying to one kind |
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