CN112816163B - Method for determining vertical rigidity of large-opening structure of rectangular fuselage cabin - Google Patents
Method for determining vertical rigidity of large-opening structure of rectangular fuselage cabin Download PDFInfo
- Publication number
- CN112816163B CN112816163B CN202011610906.7A CN202011610906A CN112816163B CN 112816163 B CN112816163 B CN 112816163B CN 202011610906 A CN202011610906 A CN 202011610906A CN 112816163 B CN112816163 B CN 112816163B
- Authority
- CN
- China
- Prior art keywords
- rectangular
- opening structure
- area
- ratio
- cross
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 25
- 230000014509 gene expression Effects 0.000 claims abstract description 31
- 238000005452 bending Methods 0.000 claims description 13
- 230000003014 reinforcing effect Effects 0.000 claims description 5
- 230000002787 reinforcement Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M5/00—Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Body Structure For Vehicles (AREA)
Abstract
The invention belongs to the field of aviation structure design, and particularly relates to a method for determining vertical rigidity of a large-opening structure of a rectangular fuselage cabin. The method comprises the following steps: setting the rigidity ratio of the rectangular airframe with the large opening structure and the rectangular airframe without the large opening structure and the rectangular section length-width wall thickness of the rectangular airframe; the two rectangular airframes are identical in structure except for a large opening structure; taking the rigidity ratio and the length, width and height of the rectangular section as parameters, taking the minimum upper side beam area and the minimum lower side beam area as constraint conditions, and solving the expression of the upper side beam area and the expression of the lower side beam area.
Description
Technical Field
The invention belongs to the field of aviation structure design, and particularly relates to a method for determining vertical rigidity of a large-opening structure of a rectangular fuselage cabin.
Background
The large opening structure cuts off the force transmission route of the aircraft structure, which is a difficulty in aircraft design. The conventional large opening of the circular fuselage is based on a small number of designs, while the rectangular opening is a special cabin opening, and is a novel structural form, the model design lacks design experience, and the airplane design information lacks the introduction of the type of structure.
In order to minimize the impact of the large open area on the fuselage and meet the requirements of continuous stiffness and consistent deformation, the open area must be reinforced. However, little technical data has been published about fuselage large opening reinforcement designs, so that design techniques and experience have been relatively lacking.
Disclosure of Invention
The invention aims to: the design principle and the method for the vertical bending rigidity of the rectangular large-opening structure of the airplane are provided for the first time, an analytical expression of the vertical rigidity ratio is deduced, and the dilemma that the design of the rectangular large-opening structure of the airplane is reinforced without theoretical basis is solved.
The technical scheme is as follows:
a method for determining the vertical rigidity of a large-opening structure of a rectangular fuselage cabin body comprises the following steps:
given a desired vertical stiffness ratio ζ of a rectangular fuselage having a large-opening structure and a rectangular fuselage having no large-opening structure and a rectangular cross-section length-width-wall thickness of the rectangular fuselage; the two rectangular airframes are identical in structure except for a large opening structure;
the sum of the upper side beam area and the lower side beam area is determined according to the length and width wall thickness of the rectangular section so as to compensate the vertical rigidity of the rectangular fuselage with the large opening structure to be up to the value of xi.
Further, determining the sum of the upper side beam area and the lower side beam area according to the rectangular cross-section length-width wall thickness comprises:
taking the rigidity ratio and the length, width and height of the rectangular section as parameters, taking the minimum sum of the upper side beam area and the lower side beam area as a constraint condition, and solving an expression of the upper side beam area and an expression of the lower side beam area;
the expression of the roof side rail area is:
the expression of the rocker area is:
wherein ,
k is the area ratio, F up For the upper side beam area F down B is rectangular cross section width; h is a rectangular section with high height; delta 0 Equal to delta is the wall thickness.
Further, determining the sum of the upper side beam area and the lower side beam area according to the rectangular cross-section length-width wall thickness, and further comprises:
drawing a set of stiffness ratio curves under the aspect ratio of the rectangular section according to the expression of the stiffness ratio; the stiffness ratio curve represents the vertical bending stiffness ratio and the cross-sectional area A of the opening reinforcing structure under different area ratios of the upper side beam and the lower side beam 1 And a cross-sectional area ratio A of the model without openings 0 Corresponding relation of (3);
searching a rigidity ratio curve corresponding to the minimum area ratio on the group of rigidity ratio curves;
finding out A corresponding to the rigidity ratio in the rigidity ratio curve corresponding to the minimum area ratio 1 /A 0 ；
According to corresponding A 1 /A 0 And calculating the sum of the areas of the upper side beam and the lower side beam according to the minimum area ratio.
Further, the calculation formula of the sum of the areas of the upper edge beam and the lower edge beam is as follows:
p＝A 1 /A 0 。
further, the stiffness ratio is expressed as:
ζ represents the stiffness ratio, EI y Rigidity of a rectangular body having a large opening structure; e (E) 0 I y0 The rigidity of the rectangular airframe without the large opening structure is E, the elastic modulus of the rectangular airframe with the large opening structure is E 0 Is the elastic modulus of a rectangular fuselage without a large opening structure, I y Is the moment of inertia of a rectangular fuselage with a large opening structure, I y0 Is the moment of inertia of a rectangular fuselage without large opening structures.
Further, the method further comprises:
establishing a model of a rectangular airframe with a large opening structure;
establishing a model of a rectangular airframe without a large opening structure;
determining an expression of rigidity of a rectangular fuselage with a large opening structure and an expression of rigidity of a rectangular fuselage without a large opening structure according to parameters of the above model;
and deforming the ratio of the two expressions to obtain an expression of the upper edge beam area and an expression of the lower edge beam area.
Further, in the coordinate system of the model of the rectangular fuselage without the large opening structure, the origin o of coordinates is the geometric center point of the cross section, the z axis is directed upward positive along the height direction of the cross section, and the y axis is directed rightward positive along the width direction of the cross section.
Further, in the coordinate system of the model of the rectangular fuselage having the large opening structure, the origin o of coordinates is the geometric center point of the cross section, the z axis is directed upward positive in the cross section height direction, and the y axis is directed rightward positive in the cross section width direction.
The beneficial effects are that:
the present invention has been developed to introduce the concept of stiffness ratio, i.e., the stiffness ratio of a large opening structure to a complete fuselage structure. The rigidity ratio is equal to 1 and is a design critical value, which indicates that the rigidity of the large opening structure of the reinforced airframe is consistent with the rigidity of the complete airframe structure; a stiffness ratio greater than 1 indicates that the structural stiffness after reinforcement is greater than the stiffness of the complete fuselage structure; a stiffness ratio less than 1 indicates that the structural stiffness after stiffening does not reach the stiffness of the complete fuselage structure.
Drawings
FIG. 1 is a schematic diagram of a large-opening structure calculation model;
FIG. 2 is a graph of a calculation model without large openings;
FIG. 3 is a graph of stiffness ratio at h/b of 0.1;
FIG. 4 is a graph of the stiffness ratio at h/b of 1;
FIG. 5 is a graph of stiffness ratio at h/b of 2;
FIG. 6 is a graph of the stiffness ratio at h/b of 5;
FIG. 7 is a graph of h/b as a stiffness ratio at 10.
Detailed Description
The invention provides a method for determining the vertical rigidity of a large opening structure of a rectangular fuselage cabin, which comprises the following steps:
(1) Establishing a large opening structure model of a rectangular airframe
For rectangular large opening structures, stiffening beams are typically arranged at four corner points, and a schematic cross-sectional view of a typical stiffened fuselage large opening structure is shown in fig. 1. The origin o of coordinates is the geometric center point of the cross section, the z-axis is directed upward along the height direction of the cross section, and the y-axis is directed rightward along the width direction of the cross section.
In fig. 1:
b-rectangular opening cross-sectional width;
h-rectangular opening profile height;
delta-rectangular opening cross-section wall thickness;
F up -the left and right side roof rail concentration areas;
F down -the concentration area of the left and right side lower side beams;
(2) Calculation model without large opening
A schematic diagram of a rectangular fuselage open-ended model is shown in fig. 2. The origin o of coordinates is the geometric center point of the cross section, the z-axis is directed upward along the height direction of the cross section, and the y-axis is directed rightward along the width direction of the cross section.
In fig. 2:
b-rectangular cross-sectional width;
h-rectangular section height;
δ 0 -no open fuselage structure wall thickness.
(3) Calculating vertical bending stiffness of large-opening structure
The bending stiffness of the model about the y-axis is defined as the vertical bending stiffness.
Due to symmetry, centroid coordinate y c ＝0
Model static moment S about y-axis y The method comprises the following steps:
the cross-sectional area A of the large opening structure is as follows:
A＝(b+2h)δ+2(F up +F down )
then centroid coordinate z c The method comprises the following steps:
the moment of inertia of the cross section to the centroid spindle y is:
will z c The expression is substituted into the above expression, and can be obtained:
vertical bending stiffness of the large opening structure is EI y
In the above formula. E is the elastic modulus of the material.
(4) Calculating vertical bending stiffness of non-opening structure
The moment of inertia of the model winding mandrel in fig. 2 is calculated as:
the vertical bending rigidity of the structure without openings is E 0 I y0
In the above formula. E (E) 0 Is the elastic modulus of the material without an opening structure.
(4) Ratio of vertical bending stiffness
The stiffness ratio ζ of the large opening structure and the large opening-free fuselage structure is:
in general, aircraft design uses aluminum alloy series materials, so e=e 0
ζ=1, indicating the stiffness EI of the large-opening structural model y Stiffness E to unopened fuselage pattern 0 I y0 In the structural design, the structural reinforcement under the condition of meeting the vertical rigidity requirement can be determined according to the expression of xi.
When determining the stiffness ratio expression, there are two approaches to solving the problem:
one is to adopt the step (5) -namely the chart method;
the other is to adopt the step (6) -formulation determination method
(5) Determination of the boundary beam area by means of a graph method
In general, in a structure of a rectangular cross section fuselage with a lower panel after opening, it is considered that the wall thickness is equal to the wall thickness before opening, and the structure is reinforced by adjusting the areas of the upper and lower side sills only, so that δ=δ 0 。
And setting a series of different upper and lower boundary beam section area values according to a rigidity ratio formula xi expression, and calculating a series of data by using excel software to make a rigidity ratio curve, wherein the rigidity ratio curve is shown in figure 3.
In the figure: a is that 1 Is the area of the opening reinforcing structure, A 0 Is a model area without openings, and has:
A 1 ＝(b+2h)δ+2(F up +F down )
A 0 ＝2(b+h)δ 0
F up /F down representing different proportions of the upper and lower side sill areas.
The corresponding stiffness ratio curves are shown in figures 3-7 according to the values of the cross-sectional dimension b/h of the rectangular large-opening airframe.
Proper reinforcing quantity xi is designed, and corresponding A is found according to a rigidity ratio curve 1 /A 0 A value, denoted p, corresponding to the abscissa axis on the graph;
from the following components
The method can obtain:
according to F corresponding to p up /F down Proportional curve, which can be defined by F up +F down The total area expression determines the values of the upper and lower boundary beam areas, respectively.
For example: check F up /F down When the curves are=2:8
Check F up /F down When the curves are=5:5
From the vertical stiffness ratio curve, the lower the area ratio of the upper side beam to the lower side beam is, the better the stiffness compensation effect is under the same area condition.
(6) Formulating to determine the upper and lower boundary beam area expression
The stiffness ratio expression is adopted, and the area ratio of the upper edge beam to the lower edge beam is set as follows:
solving the equation can be:
wherein ：
generally, the optimal solution for k is such that F up +F down And taking the corresponding value when the minimum value is taken.
Example 1
A rectangular fuselage section with a width b=3000 mm and a height h=1500 mm, wall thickness δ 0 Because the cabin body is large in opening, the lower wall needs to be reinforced by arranging side beams at four corner points, and when the vertical bending rigidity is consistent with the rigidity of the unopened model, the area F of the side beams needs to be compensated up And F is equal to down How do it determine?
The method comprises the following steps:
1) From this structural dimension data,
when the vertical bending stiffness of the model after reinforcement is required to be consistent with that of the model before opening, ζ=1;
if check F up /F down A =2:8 curve gives p=1.02.
The areas of the upper and lower side beams are respectively:
if check F up /F down =5:5 curve, obtainable: p=1.10
The areas of the upper and lower side beams are respectively:
the second method is as follows:
when the vertical bending stiffness of the model after reinforcement is required to be consistent with that of the model before opening, ζ=1; if it is
Solving the equation can be:
if it is
Solving the equation can be:
the maximum calculation error (2509.4, 2544) obtained by the two methods is 2%, which is caused by the reasons of the reading accuracy of the check chart, the calculation remaining effective digits and the like, and can be ignored in engineering.
Claims (5)
1. A method for determining the vertical rigidity of a large opening structure of a rectangular fuselage cabin is characterized by comprising the following steps:
given a desired vertical stiffness ratio ζ of a rectangular fuselage having a large-opening structure and a rectangular fuselage having no large-opening structure and a rectangular cross-section length-width-wall thickness of the rectangular fuselage; the two rectangular airframes are identical in structure except for a large opening structure;
determining the sum of the upper side beam area and the lower side beam area according to the length and width wall thickness of the rectangular section so as to compensate the vertical rigidity of the rectangular fuselage with the large opening structure to be up to the value of xi;
wherein, confirm the sum of roof side rail area and roof side rail area according to rectangle cross-section length width wall thickness, include:
taking the rigidity ratio and the length, width and height of the rectangular section as parameters, taking the minimum sum of the upper side beam area and the lower side beam area as a constraint condition, and solving an expression of the upper side beam area and an expression of the lower side beam area;
the expression of the roof side rail area is:
the expression of the rocker area is:
wherein ,
k is the area ratio, F up For the upper side beam area F down B is rectangular cross section width; h is a rectangular section with high height; delta 0 Equal to delta is the wall thickness;
the calculation formula of the sum of the areas of the upper side beam and the lower side beam is as follows:
p＝A 1 /A 0 ；
wherein ,A1 Is the cross-sectional area of the opening reinforcing structure, A 0 The cross-sectional area ratio of the model without openings is that of p;
the stiffness ratio is expressed as:
ζ represents the stiffness ratio, EI yc Rigidity of a rectangular body having a large opening structure; e (E) 0 I y0 The rigidity of the rectangular airframe without the large opening structure is E, the elastic modulus of the rectangular airframe with the large opening structure is E 0 Is the elastic modulus of a rectangular fuselage without a large opening structure, I y Is the moment of inertia of a rectangular fuselage with a large opening structure, I y0 Is free of large openingMoment of inertia of a rectangular fuselage of the mouth structure.
2. The method of claim 1, wherein determining the sum of the roof rail area and the roof rail area based on the rectangular cross-section long and wide wall thickness further comprises:
drawing a set of stiffness ratio curves under the aspect ratio of the rectangular section according to the expression of the stiffness ratio; the stiffness ratio curve represents the vertical bending stiffness ratio and the cross-sectional area A of the opening reinforcing structure under different area ratios of the upper side beam and the lower side beam 1 And a cross-sectional area ratio A of the model without openings 0 Corresponding relation of (3);
searching a rigidity ratio curve corresponding to the minimum area ratio on the group of rigidity ratio curves;
finding out A corresponding to the rigidity ratio in the rigidity ratio curve corresponding to the minimum area ratio 1 /A 0 ；
According to corresponding A 1 /A 0 And calculating the sum of the areas of the upper side beam and the lower side beam according to the minimum area ratio.
3. The method according to claim 2, wherein the method further comprises:
establishing a model of a rectangular airframe with a large opening structure;
establishing a model of a rectangular airframe without a large opening structure;
determining an expression of rigidity of a rectangular fuselage with a large opening structure and an expression of rigidity of a rectangular fuselage without a large opening structure according to parameters of the above model;
and deforming the ratio of the two expressions to obtain an expression of the upper edge beam area and an expression of the lower edge beam area.
4. A method according to claim 3, characterized in that in the coordinate system of the model of the rectangular fuselage without large opening structure, the origin o of the coordinates is the geometric center point of the cross-section, the z-axis pointing upwards in the direction of the cross-section height and the y-axis pointing to the right in the direction of the cross-section width.
5. The method according to claim 3, wherein in the coordinate system of the model of the rectangular body with the large opening structure, the origin o of the coordinates is the geometric center point of the cross section, the z-axis is directed upward along the height direction of the cross section, and the y-axis is directed rightward along the width direction of the cross section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011610906.7A CN112816163B (en) | 2020-12-29 | 2020-12-29 | Method for determining vertical rigidity of large-opening structure of rectangular fuselage cabin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011610906.7A CN112816163B (en) | 2020-12-29 | 2020-12-29 | Method for determining vertical rigidity of large-opening structure of rectangular fuselage cabin |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112816163A CN112816163A (en) | 2021-05-18 |
| CN112816163B true CN112816163B (en) | 2023-05-23 |
Family
ID=75854884
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011610906.7A Active CN112816163B (en) | 2020-12-29 | 2020-12-29 | Method for determining vertical rigidity of large-opening structure of rectangular fuselage cabin |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112816163B (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102014107674B4 (en) * | 2014-05-30 | 2017-06-29 | Airbus Operations Gmbh | Airplane door and plane with such an airplane door |
| CN109573091B (en) * | 2018-12-14 | 2022-04-19 | 中国航空工业集团公司西安飞机设计研究所 | Vertical rigidity design method for large-opening structure of airplane |
| CN109543344A (en) * | 2018-12-14 | 2019-03-29 | 中国航空工业集团公司西安飞机设计研究所 | A kind of calculation method of the vertical bending stiffness in aircraft doorframe area section |
| FR3089946B1 (en) * | 2018-12-18 | 2021-01-08 | Airbus Operations Sas | structure of a FUSELAGE OF AN aircraft presenting a panel reinforced by a trellis |
-
2020
- 2020-12-29 CN CN202011610906.7A patent/CN112816163B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112816163A (en) | 2021-05-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109573091B (en) | Vertical rigidity design method for large-opening structure of airplane | |
| CN112816163B (en) | Method for determining vertical rigidity of large-opening structure of rectangular fuselage cabin | |
| CN109543344A (en) | A kind of calculation method of the vertical bending stiffness in aircraft doorframe area section | |
| Wensheng et al. | Structural mass prediction in conceptual design of blended-wing-body aircraft | |
| US20090277011A1 (en) | Rib for aircraft wing and methods for the manufacture thereof | |
| CN108563916B (en) | Initial size optimization design method for thin-wall structure of aircraft wing fuselage | |
| CN109543345A (en) | A kind of aircraft big opening construction torsion stiffness design method | |
| CN112763166B (en) | Method for determining lateral rigidity of large-opening structure of cabin body of rectangular fuselage | |
| Rinku et al. | Topology and size optimization of modular ribs in aircraft wings | |
| CN112711803B (en) | Method for determining torsional rigidity of large-opening structure of cabin body of rectangular fuselage | |
| DeBlois et al. | Multi-fidelity multidisciplinary design optimization of metallic and composite regional and business jets | |
| CN113051657B (en) | Method for calculating bearing capacity of closed frame beam type fuselage | |
| CN114638129B (en) | Climbing capacity data obtaining method based on engine state change | |
| CN113051660B (en) | Method for calculating lateral bending stiffness of cross section of airplane fuselage doorframe area | |
| CN112623255A (en) | Method for calculating torsional rigidity of section of door frame area of airplane body | |
| CN112699485B (en) | Method for calculating torsional deformation of large opening structure of reinforced rectangular thin-wall machine body | |
| CN113051696B (en) | Method for calculating shear coefficient of single closed cell box section in airplane structure | |
| CN112699486B (en) | Reinforced rectangular fuselage large-opening structure torsion load distribution calculation method | |
| CN117932777A (en) | Accurate calculation method for torsional deformation of rectangular opening structure of reinforced fuselage | |
| CN113022613A (en) | Floor composition for magnetic levitation vehicle and magnetic levitation vehicle | |
| CN112711799B (en) | Method for calculating buckling deformation of large-opening structure of reinforced rectangular thin-wall machine body | |
| CN109711015A (en) | A kind of lateral stiffness design method of aircraft big opening structure | |
| CN117892424A (en) | Method for calculating vertical bending rigidity of large-opening structure section of double-bubble fuselage | |
| CN117910130A (en) | Method for calculating lateral bending rigidity of large-opening structure section of double-bubble fuselage | |
| CN112733257B (en) | Method for determining structural parameters of circular arch reinforcing frame bearing symmetric concentrated load |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |