CN111948043A - Buckling prediction method for stiffened wall panel under combined load action of tension, compression and shear - Google Patents
Buckling prediction method for stiffened wall panel under combined load action of tension, compression and shear Download PDFInfo
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Abstract
The application belongs to the field of design of structural strength of an airplane, and relates to a buckling prediction method for a stiffened wall panel under the action of a tension-compression-shear combined load, which comprises the following steps: obtaining a power buckling equation consisting of a tension-compression load component primary term, a tension-compression load component secondary term and a shear load component secondary term; acquiring shear buckling critical load under the action of pure shear load, and calculating the coefficient of a shear load component quadratic term; solving the coefficient of the primary term of the tension and compression load component and the coefficient of the secondary term of the tension and compression load component; and performing buckling prediction on the reinforced wall plate based on a power buckling equation formed by the coefficient of the shear load component quadratic term, the coefficient of the tension and compression load component quadratic term and the coefficient of the tension and compression load component quadratic term. The prediction of the initial buckling load of the wallboard structure under the action of the axial load and the shear load in any proportion can be completed only by single load test data of axial compression, tension and shear, and the design efficiency is greatly improved.
Description
Technical Field
The application belongs to the field of design of structural strength of airplanes, and particularly relates to a buckling prediction method for a stiffened wall panel under the action of a tension-compression-shear combined load.
Background
Composite materials are increasingly being used in aerospace vehicle structures with their excellent weight reduction properties, unique material designability and good manufacturability. However, due to the technical level of imperfection and over-conservative design criteria, the weight reduction effect of the composite structure is not ideal, especially for the panel stability structure. The thin-wall stiffened wall plate structure usually adopted by an airplane body has a long post-buckling bearing process, the skin of the metal stiffened wall plate of the wing of the subsonic airplane is usually allowed to be locally buckled at about 50% of a limit load, but the skin buckling is basically not allowed to occur below the limit load according to the structural design rule of the existing airplane composite stiffened wall plate. Therefore, solving the technical problem of post-buckling design of the composite wallboard is an effective way for further weight reduction of the composite structure, and over ten years of special research has been carried out in the technical field. Many researches have been carried out on the bending and post-bending tests and analysis of the composite material reinforced wall plate under shearing or compression load, and good effects are obtained. However, the true stress state of the aircraft panel structure is generally not a single compression or shear state, but a composite load state. For example, the upper skin of a wing is primarily subjected to compression-shear composite loads, while the lower skin is primarily subjected to tension-shear composite loads, as are the fuselage panels. The compression-shear composite load state is certainly the most severe test for structural stability, and buckling of a structure may occur with both below their buckling critical loads. But the structure will not only buckle under tensile load but also inhibit shear buckling. Therefore, over the years, one is continuously seeking a correlation equation to predict the critical value of buckling under composite loads of different proportions. In the past, a simple parabolic correlation formula is provided for an isotropic material wallboard to rapidly predict the buckling load under the tension/compression and shear composite load, and the popularization and application of the simple parabolic correlation formula to the isotropic material wallboard are attempted, but the accuracy is not satisfactory.
Disclosure of Invention
In order to solve the technical problem, the method and the system construct a correlation equation capable of accurately predicting the buckling load aiming at the reinforced wall plate structure bearing the combined load action of axial tension/compression and in-plane shear.
The application provides a method for predicting buckling of a reinforced wall plate under the action of a tension-compression-shear combined load, which comprises the following steps:
step S1, obtaining a power buckling equation composed of a tension-compression load component primary term, a tension-compression load component secondary term and a shear load component secondary term, wherein the power buckling equation is a time-series equation which indicates that the structure reaches an initial buckling critical state;
s2, acquiring shear buckling critical load under the action of pure shear load, substituting the shear buckling critical load into the power buckling equation, and calculating the coefficient of a shear load component quadratic term;
step S3, solving coefficients through test data, wherein the method comprises the steps of obtaining buckling test data under the combined action of pure compression load, pure tensile load, compression load and shearing load and gradient continuous characteristics based on buckling related functions, and solving coefficients of the primary term of the tension-compression load component and coefficients of the secondary term of the tension-compression load component; or solving coefficients through a unitary quadratic equation theory under the independent action of the axial load, wherein the method comprises the step of solving the coefficient of the primary term of the tension and compression load component and the coefficient of the secondary term of the tension and compression load component on the basis of the principle that the buckling critical load under the tensile load is infinite;
and step S4, buckling prediction is carried out on the reinforced wall plate based on a power buckling equation composed of the coefficient of the shearing load component quadratic term, the coefficient of the tension and compression load component quadratic term and the coefficient of the tension and compression load component quadratic term.
Preferably, obtaining the power-order buckling equation comprises:
step S11, expanding a buckling related function formed by the tension and compression load and the shear load to obtain a power series form function formed by a tension and compression load component and a shear load component;
a step S12 of simplifying the power series form function by rounding off higher-order terms of three or more times;
and step S13, setting the first order coefficient of the shearing load component to be zero according to the principle that positive and negative shearing loads have the same influence on structural instability, so as to form a power buckling equation comprising three unknowns, wherein the three unknowns respectively comprise a first waiting coefficient related to the first order of the tension and compression load component, a second waiting coefficient related to the second order of the tension and compression load component and a third waiting coefficient related to the second order of the shearing load component.
Preferably, in step S3, solving the coefficients by experimental data includes:
for a power buckling equation under the action of compression and shearing composite loads, acquiring a compression buckling critical load under the action of a pure compression load and a composite buckling critical load under the combined action of the compression load and the shearing load in any proportion to form two equations, and solving to obtain a coefficient of a primary term of a tension-compression load component and a coefficient of a secondary term of the tension-compression load component;
for a power buckling equation under the combined action of tensile load and shear load, acquiring the combined buckling critical load under the combined action of compressive load and shear load of any proportion, constructing a first equation, determining the gradient continuity of the power buckling equation at the position where the tensile load is zero according to the curve smoothness characteristic of a buckling related equation, thereby constructing a second equation, establishing the first equation and the second equation in a simultaneous manner, and solving to obtain the coefficient of the tension-compression load component primary term and the coefficient of the tension-compression load component secondary term.
Preferably, in step S3, the theoretical solution of the coefficients by a quadratic one-dimensional equation under the action of the axial load alone includes:
converting a power buckling equation under the independent action of the axial load into a one-dimensional quadratic equation;
determining that the coefficient of the tension and compression load component quadratic term is zero according to the Vida's theorem and the principle that the buckling critical load under the tensile load is infinite, and forming a linear equation of a unary of the coefficient only containing the tension and compression load component quadratic term;
and obtaining the critical buckling load under the compression load, substituting the critical buckling load into the linear equation of unity, and solving the coefficient of the primary term of the tension-compression load component.
Preferably, the power-order buckling equation in step S1 is:
wherein the content of the first and second substances,
in order to pull and press the load,
in order to shear the load,A 1 ，A 2 andB 2 is the undetermined coefficient.
The method has the advantages that the physical mechanisms under the action of the tension-shear composite load and the compression-shear composite load are fully considered, the related equation of the buckling load of the isotropic and orthotropic stiffened wall plate structure under the action of the composite load is innovatively provided, and compared with the traditional buckling load prediction method, the prediction precision is higher. In addition, a large amount of test data, particularly test data under the action of a composite load, are not needed, and the prediction of the initial buckling load of the wallboard structure under the action of the axial load and the shear load in any proportion can be completed only by single load test data of axial compression, tension and shear. The test cost is greatly reduced, the design efficiency is improved, and the evaluation result is real and reliable.
Drawings
Fig. 1 is a flowchart of a method for predicting buckling of a stiffened wall panel under combined tension-compression-shear loading according to a preferred embodiment of the present invention.
Fig. 2 is a schematic view of the embodiment of the present application in fig. 1 showing the ribbed panel under load.
FIG. 3 is a comparison of the predicted results of buckling-related curves under axial tension-compression-shear loading of the embodiment shown in FIG. 1 of the present application and the results of the test.
The method comprises the following steps of 1-base, 2-corner box, 3-ribbed wallboard, 4-shear pulling plate, 5-side loading joint and 6-filling end.
Detailed Description
In order to make the implementation objects, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all embodiments of the present application. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application, and should not be construed as limiting the present application. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application. Embodiments of the present application will be described in detail below with reference to the drawings.
The application aims at the orthotropic composite material reinforced wall plate structure and is also suitable for the isotropic reinforced wall plate structure. Where isotropic material means that the properties of the elastomer are the same in all directions, or the material is symmetrical about any plane. Orthotropic materials, on the other hand, mean materials in which there are three mutually perpendicular planes of symmetry at any point through the material, the direction perpendicular to the planes of symmetry being referred to as the principal direction of elasticity, in which the elastic properties of the material are the same. Isotropy is a special case of orthotropic anisotropy. In both cases, the direction of the shear stress does not influence the magnitude of the mechanical response. The method can well predict the buckling load of the wall plate under the action of any composite load proportion, improves the accuracy of the structural stability evaluation of the wall plate, and is beneficial to improving the structural design level.
After the single axial load and shear load tests of the reinforced wall plate are respectively completed, the buckling load of the wall plate under the action of the composite load in any proportion can be predicted by using the obtained buckling load under the action of the single axial load, and the method mainly comprises the following steps:
(1) by axial tension-compression loading
And shear load
Constructing a buckling correlation function of a reinforced wall plate structure; (2) expanding a function expression, and obtaining a simplified buckling correlation equation by omitting a high-order term and setting a first-order term coefficient of the shearing load to be 0; (3) the undetermined coefficient can be determined according to the buckling critical load under the action of pure shear loadB 2 (ii) a (4) Respectively considering different action mechanisms of the compression load and the tensile load, and determining buckling related equations of the compression-shear composite load and the tensile-shear composite load; (5) buckling critical load under independent action of axial compressive load and compressive-shear composite buckling critical load of any proportion (
) Determining the undetermined coefficients
，
(ii) a (6) Buckling critical load under consideration of tensile load under single action
And typically a buckling-related function in
The gradient continuity is satisfied, and undetermined coefficients can be determined
，
Determining a buckling correlation equation under the joint action of the axial load and the shearing load; (7) and the positive and negative solutions of the buckling correlation equation can be conditionally determined by the Vida theorem according to the physical mechanism of the reinforced wall plate under the action of the axial load, and the buckling correlation equation under the joint action of the axial load and the shearing load is finally determined by single load test data.
As shown in fig. 1, the method for predicting buckling of a stiffened wall panel under combined tension-compression-shear loading provided by the present application comprises:
and step S1, obtaining a power buckling equation composed of a tension-compression load component primary term, a tension-compression load component secondary term and a shear load component secondary term, wherein the power buckling equation is a time which indicates that the structure reaches an initial buckling critical state.
And S2, acquiring the shear buckling critical load under the action of the pure shear load, substituting the shear buckling critical load into the power buckling equation, and calculating the coefficient of the shear load component quadratic term.
Step S3, solving coefficients through test data, wherein the method comprises the steps of obtaining buckling test data under the combined action of pure compression load, pure tensile load, compression load and shearing load and gradient continuous characteristics based on buckling related functions, and solving coefficients of the primary term of the tension-compression load component and coefficients of the secondary term of the tension-compression load component; or solving coefficients through a unitary quadratic equation theory under the independent action of the axial load, wherein the method comprises the step of solving the coefficient of the primary term of the tension and compression load component and the coefficient of the secondary term of the tension and compression load component on the basis of the principle that the buckling critical load under the tensile load is infinite.
And step S4, buckling prediction is carried out on the reinforced wall plate based on a power buckling equation composed of the coefficient of the shearing load component quadratic term, the coefficient of the tension and compression load component quadratic term and the coefficient of the tension and compression load component quadratic term.
Referring to fig. 2, the test piece according to the present embodiment is a composite stiffened panel, and the stiffened panel 3 is composed of a skin, stringers, frames, side stiffeners, and a cast-in end 6, and includes 5 hat stringers and 2 fuselage frames, wherein the stringer pitch is 210mm and the fuselage frame pitch is 620 mm. The skin, stringers and side stiffener material are M21E/epoxy composite. The fuselage frame is composed of an L-shaped shearing angle piece and a Z-shaped floating frame, and the frame is made of aluminum alloy (2024-T42). The stringer and the skin are formed by adopting a co-bonding process, and the frame is connected with the skin, and the L-shaped shear angle piece and the Z-shaped floating frame are connected through bolts.
The test is carried out on a novel compression-shear composite load wallboard test system, referring to fig. 2, the reinforced wallboard is fixed on a base 1 of a compression-shear composite loading device through an angle box 2, namely, the wallboard integrally adopts a supporting mode of three free sides and bottom edge fixing. The compressive load is applied to the upper potting head 6 through a spherical loading head above the test piece. Shear loads are applied through shear tie plates 4 and side loading joints 5, the loading direction being referenced to the arrows in fig. 2. In a test, compression and shear loads can be independently loaded, and compression and shear composite loads of any proportion can be cooperatively applied, for example, in a certain test, a compression load of 238kN is applied, and a structure is buckled after a shear load of 315kN is applied.
In some alternative embodiments, step S1 further includes:
step S11: constructing a buckling related function and an unfolding buckling related function of the reinforced wall plate structure;
the load causing the structure failure mainly comprises two forms of axial compression and shearing, and the axial tension can not cause the buckling of the structure but can inhibit the occurrence of the shearing buckling, so the load is pulled and pressed in the axial direction
And shear load
Constructing a buckling correlation function of the reinforced wall plate structure:
unfolding the buckling related function;
the buckling-related function is expanded into two load components (
) Power series form of (1):
wherein … represents terms of higher order of three or more.
Step S12: simplifying a buckling correlation equation;
usually the quadratic polynomial has sufficient accuracy to fit the experimental data, so equation (2) can be cut off to the quadratic term, i.e.:
step S13: for isotropic and orthotropic structures, the positive and negative shear loads have the same effect on structural instability, so the shear load is the same in equation (3)
The coefficient related to the first order term must be 0, so that the correlation function
Can be simplified as follows:
in the formula (I), the compound is shown in the specification,A 1 ，A 2 andB 2 is the undetermined coefficient. When in use
When, it means that the structure is not buckled, when
When it is time, it indicates that the structure has reached the initial buckling threshold. The buckling-related equation can be expressed as:
in step S2, the undetermined coefficient is determinedB 2 ；
The buckling load of the reinforced wall plate under the action of the axial load can be obtained by tests, and the buckling critical load under the action of the pure shear load is taken into the formula (5) to obtain:
where is the shear buckling threshold.
In this step, no specific undetermined coefficient needs to be calculatedB 2 The main purpose is to determine the undetermined coefficientB 2 Expressed in terms of known shear critical buckling loads, thereby reducing unknowns.
Step S3 provides two calculationsA 1 ，A 2 The method (1). One way is to solve the coefficients through experimental data, and the other way is to solve the coefficients through a one-dimensional quadratic equation theory under the independent action of the axial load. The following are described separately.
Solving coefficients through experimental data comprises:
step S31, determining a correlation equation of the compression-shear composite load and the tension-shear composite load;
since axial compressive loads can cause buckling of the wall plate, tensile loads do not, and shear buckling of the wall plate can be suppressed, it is necessary to consider axial compression and tension differently, taking into account the fact that the one obtained in step 2B 2 Substitution formula (5):
Step S32, determining the compression-shear combined loading effect (
) The undetermined coefficient of the time is determined,
；
buckling critical load under independent action of axial compression load
The tape-in (7) can be obtained:
there are two unknown coefficients in equation (9)
And
therefore, additional boundary conditions are required to determine. With the development of the compression-shear composite test technology of the wallboard, the buckling load of the wallboard in a compression-shear composite state can be obtained easily. (iii) the compression-shear composite buckling critical load of any proportion: (
) The tape-in (7) can be obtained:
the united type (9) and the formula (10) are solved:
from this step, the buckling correlation equation can be determined
And
value of wherein
In the form of a chip of-0.001067421,
is 4.87299E-07.
Step S33. Determination of tensile-shear composite load Effect (
) Undetermined coefficient of time
；
Under the independent action of axial tensile load, buckling of the reinforced wall plate structure cannot occur, namely buckling load
The belt (8) can be:
in this case, the formula (8) also has a coefficient
It is not determined. Of course, it can be determined by the tensile-shear combination load test, but since the tensile load inhibits shear buckling, the buckling load can be so large that the tensile-shear test is difficult to perform. In addition, the tensile-shear compounding state is not a serious working condition of structural load bearing, and the tensile-shear compounding test is not generally carried out in a verification test. There is a need to establish a reasonably feasible method for determining another equation to determine the coefficients without relying on additional experimental data
。
The buckling-related equation is usually a smooth convex curve, i.e. in
The gradient of the buckling-related function continues:
from formula (14):
from this step, the buckling correlation equation can be determined
And
value of wherein
In the form of a chip of-0.001067421,
is 0.
Step S34, determining a buckling correlation equation under the joint action of the axial load and the shearing load;
up to this point, all pending coefficients can be determined through steps S2, S32, S33. For convenience of expression, let:
the buckling correlation equation under the combined action of the axial load and the shear load can be obtained by taking the formula (7) and the formula (8):
(II) the theoretical solving coefficient of the quadratic equation of a unary under the single action of the axial load comprises the following steps:
step S35, determining a buckling correlation equation under the joint action of the axial load and the shear load according to the single load test data;
but if the compression-shear composite load test data is missing, the correlation equation cannot be obtained. Therefore, it is necessary to find another way to determine the coefficients of the buckling-related function. It can be noted that under the sole action of the axial load, equation (5) becomes a one-dimensional quadratic equation:
according to a physical mechanism of the reinforced wall plate under the action of the axial load, the unitary quadratic equation only has two real solutions of positive and negative, the positive solution is the buckling critical load under the tensile load, the negative solution is the buckling critical load under the compressive load, and the buckling critical load under the tensile load is infinite. According to the wedda theorem, two solutions of the equation satisfy the following condition:
to make one of the solutions infinite, there must be:
then the critical buckling load under the compression load is measured
The tape-in formula (21) is readily available:
the buckling-related equation under the combined action of the axial load and the shear load can then be expressed as:
the formula (16) and the formula (17) may be taken into the formula (26):
equation (27) is the buckling-related equation for the panel that can take into account both the compressive-shear combined load and the tensile-shear combined load effects.
From the steps S34 and S35, the critical buckling load under any ratio of axial load to shear load can be determined, as shown in table 1, and table 1 shows the critical buckling load under any ratio of axial load to shear load predicted by two buckling-related equations. Wherein the value is any value between-1 and 1. The buckling envelope calculated in this application (as shown in FIG. 3) may cover the critical buckling load at any ratio of axial load to shear load. The result shows that the predicted buckling related curve has good consistency with the test result, and the curve predicted by the buckling related equation which separately considers tension/compression and is provided by the patent has higher goodness of fit with the test result. Due to the lack of tensile test data, the buckling correlation equation of the wall plate under the action of the tensile-shear combined load cannot be verified, but the wall plate cannot buckle under the axial tensile load, and the buckling load of the wall plate under the shear can be improved by stretching, which is consistent with the trend predicted by the two correlation equations in fig. 3.
Table 1:
the method has the advantages that the physical mechanisms under the action of the tension-shear composite load and the compression-shear composite load are fully considered, the related equation of the buckling load of the isotropic and orthotropic stiffened wall plate structure under the action of the composite load is innovatively provided, and compared with the traditional buckling load prediction method, the prediction precision is higher. In addition, a large amount of test data, particularly test data under the action of a composite load, are not needed, and the prediction of the initial buckling load of the wallboard structure under the action of the axial load and the shear load in any proportion can be completed only by single load test data of axial compression, tension and shear. The test cost is greatly reduced, the design efficiency is improved, and the evaluation result is real and reliable.
Claims (5)
1. A buckling prediction method of a stiffened wall panel under combined tension, compression and shear loading is used for buckling prediction of the stiffened wall panel under combined tension, compression and shear loading, wherein the stiffened wall panel is made of composite materials, and the method comprises the following steps:
step S1, obtaining a power buckling equation composed of a tension-compression load component primary term, a tension-compression load component secondary term and a shear load component secondary term, wherein the power buckling equation is a time-series equation which indicates that the structure reaches an initial buckling critical state;
s2, acquiring shear buckling critical load under the action of pure shear load, substituting the shear buckling critical load into the power buckling equation, and calculating the coefficient of a shear load component quadratic term;
step S3, solving coefficients through test data, wherein the method comprises the steps of obtaining buckling test data under the combined action of pure compression load, pure tensile load, compression load and shearing load and gradient continuous characteristics based on buckling related functions, and solving coefficients of the primary term of the tension-compression load component and coefficients of the secondary term of the tension-compression load component; or solving coefficients through a unitary quadratic equation theory under the independent action of the axial load, wherein the method comprises the step of solving the coefficient of the primary term of the tension and compression load component and the coefficient of the secondary term of the tension and compression load component on the basis of the principle that the buckling critical load under the tensile load is infinite;
and step S4, buckling prediction is carried out on the reinforced wall plate based on a power buckling equation composed of the coefficient of the shearing load component quadratic term, the coefficient of the tension and compression load component quadratic term and the coefficient of the tension and compression load component quadratic term.
2. A method of predicting buckling of a stiffened panel under combined tension-compression-shear loading according to claim 1, wherein obtaining the power-order buckling equation comprises:
step S11, expanding a buckling related function formed by the tension and compression load and the shear load to obtain a power series form function formed by a tension and compression load component and a shear load component;
a step S12 of simplifying the power series form function by rounding off higher-order terms of three or more times;
and step S13, setting the first order coefficient of the shearing load component to be zero according to the principle that positive and negative shearing loads have the same influence on structural instability, so as to form a power buckling equation comprising three unknowns, wherein the three unknowns respectively comprise a first waiting coefficient related to the first order of the tension and compression load component, a second waiting coefficient related to the second order of the tension and compression load component and a third waiting coefficient related to the second order of the shearing load component.
3. The method for predicting buckling of a stiffened panel under combined tension-compression-shear loading of claim 1, wherein in step S3, solving coefficients from experimental data comprises:
for a power buckling equation under the action of compression and shearing composite loads, acquiring a compression buckling critical load under the action of a pure compression load and a composite buckling critical load under the combined action of the compression load and the shearing load in any proportion to form two equations, and solving to obtain a coefficient of a primary term of a tension-compression load component and a coefficient of a secondary term of the tension-compression load component;
for a power buckling equation under the combined action of tensile load and shear load, acquiring the combined buckling critical load under the combined action of compressive load and shear load of any proportion, constructing a first equation, determining the gradient continuity of the power buckling equation at the position where the tensile load is zero according to the curve smoothness characteristic of a buckling related equation, thereby constructing a second equation, establishing the first equation and the second equation in a simultaneous manner, and solving to obtain the coefficient of the tension-compression load component primary term and the coefficient of the tension-compression load component secondary term.
4. The method for predicting buckling of a stiffened panel under combined tension-compression-shear loading of claim 1, wherein in step S3, solving coefficients by a one-dimensional quadratic theory under the action of axial load alone comprises:
converting a power buckling equation under the independent action of the axial load into a one-dimensional quadratic equation;
determining that the coefficient of the tension and compression load component quadratic term is zero according to the Vida's theorem and the principle that the buckling critical load under the tensile load is infinite, and forming a linear equation of a unary of the coefficient only containing the tension and compression load component quadratic term;
and obtaining the critical buckling load under the compression load, substituting the critical buckling load into the linear equation of unity, and solving the coefficient of the primary term of the tension-compression load component.
5. The method for predicting buckling of a stiffened panel under combined tension-compression-shear loading of claim 1, wherein the power-order buckling equation in step S1 is:
wherein the content of the first and second substances,
in order to pull and press the load,
in order to shear the load,A 1 ，A 2 andB 2 is the undetermined coefficient.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112816323A (en) * | 2020-12-29 | 2021-05-18 | 中国航空工业集团公司西安飞机设计研究所 | Method for judging shear buckling load of body wall plate |
Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100231208A1 (en) * | 2006-06-23 | 2010-09-16 | Raymond Huggett | Vibration and condition monitoring system and the parts thereof |
| CN103033418A (en) * | 2012-12-10 | 2013-04-10 | 中国飞机强度研究所 | Test device capable of evenly applying axial compression load and shearing load |
| CN103559390A (en) * | 2013-10-22 | 2014-02-05 | 北京航空航天大学 | Composite material Pi-shaped gluing connection structure tensile strength prediction method based on average invalidation index |
| US20140297207A1 (en) * | 2013-03-29 | 2014-10-02 | Mitsubishi Aircraft Corporation | Safety analysis system for wiring |
| CN104881576A (en) * | 2015-05-15 | 2015-09-02 | 中国电力科学研究院 | Calculation method of elastic-plastic buckling load of axially-compressed component |
| US20150316458A1 (en) * | 2014-05-01 | 2015-11-05 | Metriguard Inc | Rail Shear Tester Apparatus with multiple loading configurations |
| US20160139016A1 (en) * | 2014-11-19 | 2016-05-19 | The Boeing Company | Combined loading in composite materials |
| CN107066658A (en) * | 2016-12-23 | 2017-08-18 | 中国船舶工业集团公司第七0八研究所 | A kind of Loading End contracting curve of the deck longitudinal beam column flexing of cantilever beams support determines method |
| CN107423468A (en) * | 2017-04-20 | 2017-12-01 | 南京航空航天大学 | A kind of PRSEUS structure analysis methods based on equivalent method |
| CN107506529A (en) * | 2017-08-01 | 2017-12-22 | 中国航空工业集团公司西安飞机设计研究所 | A kind of Composite Material Stiffened Panel Axial Compression Stability computational methods |
| CN108153981A (en) * | 2017-12-26 | 2018-06-12 | 中航沈飞民用飞机有限责任公司 | A kind of composite material fuselage Material Stiffened Panel Post-Buckling Analysis of Structures method based on finite element analysis |
| CN110887737A (en) * | 2019-12-24 | 2020-03-17 | 中国航空工业集团公司西安飞机设计研究所 | Method for determining pressure loss strength test of composite material reinforced wall plate |
-
2020
- 2020-07-24 CN CN202010724994.7A patent/CN111948043B/en active Active
Patent Citations (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100231208A1 (en) * | 2006-06-23 | 2010-09-16 | Raymond Huggett | Vibration and condition monitoring system and the parts thereof |
| CN103033418A (en) * | 2012-12-10 | 2013-04-10 | 中国飞机强度研究所 | Test device capable of evenly applying axial compression load and shearing load |
| US20140297207A1 (en) * | 2013-03-29 | 2014-10-02 | Mitsubishi Aircraft Corporation | Safety analysis system for wiring |
| CN103559390A (en) * | 2013-10-22 | 2014-02-05 | 北京航空航天大学 | Composite material Pi-shaped gluing connection structure tensile strength prediction method based on average invalidation index |
| US20150316458A1 (en) * | 2014-05-01 | 2015-11-05 | Metriguard Inc | Rail Shear Tester Apparatus with multiple loading configurations |
| US20160139016A1 (en) * | 2014-11-19 | 2016-05-19 | The Boeing Company | Combined loading in composite materials |
| CN104881576A (en) * | 2015-05-15 | 2015-09-02 | 中国电力科学研究院 | Calculation method of elastic-plastic buckling load of axially-compressed component |
| CN107066658A (en) * | 2016-12-23 | 2017-08-18 | 中国船舶工业集团公司第七0八研究所 | A kind of Loading End contracting curve of the deck longitudinal beam column flexing of cantilever beams support determines method |
| CN107423468A (en) * | 2017-04-20 | 2017-12-01 | 南京航空航天大学 | A kind of PRSEUS structure analysis methods based on equivalent method |
| CN107506529A (en) * | 2017-08-01 | 2017-12-22 | 中国航空工业集团公司西安飞机设计研究所 | A kind of Composite Material Stiffened Panel Axial Compression Stability computational methods |
| CN108153981A (en) * | 2017-12-26 | 2018-06-12 | 中航沈飞民用飞机有限责任公司 | A kind of composite material fuselage Material Stiffened Panel Post-Buckling Analysis of Structures method based on finite element analysis |
| CN110887737A (en) * | 2019-12-24 | 2020-03-17 | 中国航空工业集团公司西安飞机设计研究所 | Method for determining pressure loss strength test of composite material reinforced wall plate |
Non-Patent Citations (2)
| Title |
|---|
| CHEN X. ET AL.: "A delamination failure criterion considering the effects of through-thickness compression on the interlaminar shear failure of composite laminates", 《COMPOSITE STRUCTURES》 * |
| 王彬文 等: "考虑不确定性的复合材料加筋壁板后屈曲分析模型验证方法", 《航空学报》 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112816323A (en) * | 2020-12-29 | 2021-05-18 | 中国航空工业集团公司西安飞机设计研究所 | Method for judging shear buckling load of body wall plate |
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