Baffle door corner piece and design method thereof

Abstract

The invention relates to the technical field of space flight and aviation, and discloses a baffle door corner piece and a design method thereof.The design method of the baffle door corner piece comprises the following steps that S1, the fatigue service life A of an original factory baffle door corner piece is obtained; s2, establishing a first finite element model of the original factory baffle door corner piece and the separated tool, performing a tensile test on the first finite element model, and obtaining a displacement load M applied by the first finite element model when the fatigue service life A is reached; s3, the original factory baffle door corner piece is installed on the separation type tool to be subjected to a tensile test, a displacement load M is applied to the separation type tool, and the fatigue service life B of the original factory baffle door corner piece is obtained; and S4, the inner fillet radius of the fillet part of the first finite element model is adjusted to obtain a second finite element model, so that the second finite element model has the fatigue service life C when the displacement load M is applied to the second finite element model for a tensile test, and the baffle door corner piece in the second finite element model is obtained.

Description

Technical Field

[0001] This invention relates to the field of aerospace technology, and in particular to a baffle gate corner plate and its design method. Background Technology

[0002] The CFM56-5B engine nacelle thrust reverser deflector is a thrust reverser device used during aircraft landing to generate reverse thrust by changing the direction of engine exhaust flow, thus helping to decelerate the aircraft. To connect the deflector body, deflector frame, and guard plate, deflector corner pieces are typically used. The deflector corner pieces consist of a first sheet and a second sheet integrally formed and connected by rounded corners. The first sheet is used to connect to the deflector frame or guard plate, and the second sheet is used to connect to the deflector body.

[0003] However, the rounded corners of the original baffle gate plates are prone to cracking, resulting in a short fatigue life and requiring frequent replacement or repair. This disrupts flight operations and causes significant economic losses. Therefore, improving the fatigue life of baffle gate plates is a research trend. However, without understanding the loads that the original baffle gate plates bear in actual applications, redesigning them to improve their lifespan requires modifying the structure of each baffle gate plate during manufacturing. Each new baffle gate plate must then be tested for cracking at the rounded corners and its fatigue life in real-world scenarios. This process is time-consuming and resource-intensive, making it difficult to quickly and accurately obtain baffle gate plates with improved fatigue life. Summary of the Invention

[0004] The purpose of this invention is to provide a baffle gate corner piece and its design method, which can more quickly and accurately obtain a baffle gate corner piece with improved fatigue service life.

[0005] To achieve the above objectives, the present invention provides a design method for a baffle corner plate. The baffle corner plate includes a first sheet and a second sheet integrally formed and connected by rounded corner portions. The design method for the baffle corner plate includes the following steps: S1. Obtain the fatigue service life A of the original factory baffle corner plate; S2. Establish the first finite element model of the original factory baffle door corner piece and the separate tooling, perform a tensile test on the first finite element model, and obtain the displacement load M applied to the first finite element model when it reaches the fatigue service life A. S3. Install the original factory baffle corner plate on the separate tooling for tensile testing, and apply the displacement load M to the separate tooling to obtain the fatigue service life B of the original factory baffle corner plate. S4. When the difference between the fatigue service life A and the fatigue service life B is within the preset error range, the inner radius of the rounded corner of the first finite element model is adjusted to obtain the second finite element model. When the second finite element model is subjected to the displacement load M for tensile testing, the second finite element model has a fatigue service life C, and the baffle corner piece in the second finite element model is obtained. Where B > A, then C > B; and A > B, then C > A.

[0006] Preferably, obtaining the fatigue life A of the original factory baffle corner plate specifically includes: The fatigue life of the original factory baffle door corner plate conforms to a two-parameter Weibull distribution function. According to the formula Calculate , Let A be the fatigue service life of the original factory baffle corner plate, where, β Characteristic lifetime, , n This represents the sample size. N The fatigue life corresponding to each sample For shape parameters, S T For specimen coefficient, S C Here is the confidence coefficient. S R This represents the reliability coefficient.

[0007] Preferably, establishing the first finite element model of the original factory baffle door corner plate and the separate tooling specifically includes: A first finite element model of the original baffle door corner plate and the separate tooling is established, so that the stress and strain values ​​of the rounded corner crack region of the first finite element model converge at the mesh density.

[0008] Preferably, obtaining the displacement load M applied to the first finite element model when it reaches the fatigue service life A specifically includes: Obtain the average stress of the first finite element model under cyclic stress and strain under different displacement loads. and strain amplitude According to the formula Calculate fatigue service life N When the fatigue service life N When the fatigue service life A is equal to the specified fatigue service life, the corresponding displacement load is the displacement load M, where, The fatigue strength coefficient, For elastic modulus, The fatigue strength index is related to the material. It is the fatigue ductility index. is the fatigue ductility coefficient of the material.

[0009] Preferably, the step of obtaining the average stress of the first finite element model under different displacement loads is... and strain amplitude Specifically, it includes: According to the formula , and The local plastic deformation under different displacement loads was calculated. This leads to the corrected local maximum stress value. and local maximum strain value ,in, The effective stress concentration factor, This is the local maximum stress value before correction. It is the elastic modulus of the material. It is the strength coefficient. It is the strain hardening index; Obtain the minimum stress and minimum strain values ​​of the first finite element model without applied displacement load, and combine them with the local maximum stress value. and local maximum strain value The average stress of the first finite element model under different displacement loads was obtained. and strain amplitude .

[0010] Preferably, both the first sheet and the second sheet extend along a first direction, and the second sheet and the first sheet are arranged sequentially along a second direction, with the first sheet bent toward the direction close to the second sheet to form the rounded corner portion; The detachable tooling includes a lower clamp and an upper clamp arranged sequentially along a second direction; the lower clamp includes a lower fixing part and a lower contact plate connected sequentially along the second direction, the side of the lower contact plate in a third direction matches the side of the second sheet away from the first sheet in a third direction, and the lower contact plate extends along a first direction; the upper clamp includes an upper contact plate and an upper loading part connected sequentially along the second direction, the side of the upper contact plate near the lower contact plate in the second direction matches the side of the first sheet away from the second sheet in the second direction, and the upper contact plate extends along the first direction; The first direction, the second direction, and the third direction intersect each other perpendicularly.

[0011] This invention provides a baffle door corner piece, which is obtained by the above-mentioned design method of the baffle door corner piece, including: an integrally formed first sheet and a second sheet, both the first sheet and the second sheet extending along a first direction, the second sheet and the first sheet being arranged sequentially along a second direction, the first sheet being bent towards the second sheet to form a rounded corner, the inner radius of the rounded corner being D, 4.0mm < D < 6.0mm; The first direction and the second direction intersect each other perpendicularly.

[0012] Preferably, the inner radius D of the rounded corner is greater than 4.0 mm and less than 5.0 mm.

[0013] Preferably, the inner radius D of the rounded corner is 4.5 mm.

[0014] Preferably, the first sheet has a plurality of first holes evenly distributed in sequence along a first direction, and the second sheet has a plurality of second holes evenly distributed in sequence along a first direction, with the first holes and the second holes arranged alternately.

[0015] Compared with the prior art, the design method of the baffle door corner piece of this invention has the following advantages: By obtaining the fatigue life A of the original factory baffle corner plate, finite element modeling of the original factory baffle corner plate and the separate tooling was performed, and tensile tests were conducted to obtain the displacement load M required for the model to reach the fatigue life A. Then, the actual original factory baffle corner plate was installed on the separate tooling, and the displacement load M was applied for tensile tests to obtain the fatigue life B. When the difference between A and B is within the preset error range, it proves that the displacement load M obtained by the tensile test of the finite element model can reflect the load situation of the actual baffle corner plate in actual application.

[0016] By repeatedly adjusting the inner corner radius of the baffle plate in the first finite element model, multiple second finite element models can be obtained. Tensile tests are performed on the multiple second finite element models under displacement load M to obtain fatigue service life C. The second finite element model with a fatigue service life C that is greater than both A and B is selected. The baffle plate corresponding to this second finite element model has an improved fatigue service life compared to the original baffle plate.

[0017] The above design method yields a baffle plate structure that improves fatigue life. By manufacturing based on this structure, baffle plates with improved fatigue life can be obtained more quickly and accurately. This eliminates the need to manufacture baffle plates with different structures multiple times for practical application and testing, saving time and human resources. Attached Figure Description

[0018] Figure 1This is a flowchart of the design method for the baffle gate corner plate according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of the baffle corner plate according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the detachable tooling described in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the baffle corner plate installed on the separate tooling according to an embodiment of the present invention; In the figure, 1 is the baffle corner piece; 11 is the first sheet; 111 is the first hole; 12 is the second sheet; 121 is the second hole; 13 is the rounded corner; 2 is the detachable tooling; 21 is the upper clamp; 211 is the upper loading part; 212 is the upper contact plate; 22 is the lower clamp; 221 is the lower contact plate; and 222 is the lower fixing part. Detailed Implementation

[0019] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0020] In the description of this invention, it should be understood that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this invention based on the specific circumstances.

[0021] In the description of this invention, it should be understood that the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," "longitudinal," "X-axis direction," "Y-axis direction," and "Z-axis direction," etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention. Moreover, some of the above terms, in addition to indicating orientations or positional relationships, may also be used to indicate other meanings; for example, the term "upper" may in some cases be used to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances.

[0022] like Figure 1-2 As shown, an embodiment of the present invention discloses a design method for a baffle corner plate. The baffle corner plate 1 includes a first sheet 11 and a second sheet 12 integrally formed and connected by a rounded corner portion 13. The design method of the baffle corner plate 1 includes the following steps: S1. Obtain the fatigue service life A of the original factory baffle corner plate; S2. Establish the first finite element model of the original factory baffle corner plate and the separate tooling 2, perform a tensile test on the first finite element model, and obtain the displacement load M applied to the first finite element model when it reaches the fatigue service life A. S3. Install the original baffle corner plate on the separate fixture 2 for tensile testing, and apply displacement load M to the separate fixture 2 to obtain the fatigue service life B of the original baffle corner plate. S4. When the difference between fatigue service life A and fatigue service life B is within the preset error range, adjust the inner radius of the fillet 13 of the first finite element model to obtain the second finite element model. When the second finite element model is subjected to a displacement load M for tensile testing, the second finite element model has a fatigue service life C, and the baffle corner piece 1 in the second finite element model is obtained. Where B > A, then C > B; and A > B, then C > A.

[0023] It should be noted that by obtaining the fatigue service life A of the original factory baffle corner plate, a tensile test was performed on the original factory baffle corner plate and the separate tooling 2 after finite element modeling. The displacement load M required for the model to reach the fatigue service life A was obtained. Then, the actual original factory baffle corner plate was installed on the separate tooling 2 and the displacement load M was applied for a tensile test to obtain the fatigue service life B. When the difference between A and B is within the preset error range, it proves that the displacement load M obtained by the tensile test of finite element modeling can reflect the load situation of the baffle corner plate 1 in actual application.

[0024] By repeatedly adjusting the inner corner radius of the baffle plate 1 in the first finite element model, multiple second finite element models can be obtained. Tensile tests are performed on the multiple second finite element models under displacement load M to obtain fatigue service life. The second finite element model with a fatigue service life C that is greater than both A and B is selected. The fatigue service life of the baffle plate 1 corresponding to this second finite element model is improved compared with the original baffle plate.

[0025] The above design method yields a baffle plate 1 structure that can improve fatigue service life. Based on this structure, actual manufacturing can be carried out more quickly and accurately to obtain a baffle plate 1 with improved fatigue service life. This eliminates the need to manufacture baffle plate 1 with different structures multiple times for practical application and testing, saving time and human resources.

[0026] The difference between fatigue service life A and fatigue service life B is within the preset error range, specifically -100≤AB≤100. The difference between fatigue service life B and fatigue service life A obtained from actual experiments in this application is within 10 cycles, showing a high degree of agreement and demonstrating the extremely high reliability of the finite element modeling.

[0027] Comparative example: The inner radius of the fillet 13 of the first finite element model is 4mm, the fatigue service life A is 2541 cycles, and the fatigue service life B is 2540 cycles.

[0028] Example 1: The inner radius of the fillet 13 in the finite element model is 3.9 mm, and the fatigue service life is reduced compared to the fatigue service life A.

[0029] Example 2: The inner radius of the fillet 13 of the finite element model is 4.2 mm, and the fatigue service life is increased by 13% compared with the fatigue service life A.

[0030] Example 3: The inner radius of the fillet 13 of the finite element model is 4.4 mm, and the fatigue service life is increased by 63% compared with the fatigue service life A.

[0031] Example 4: The inner radius of the fillet 13 of the finite element model is 4.5mm, and the fatigue service life is increased by 109% compared with the fatigue service life A.

[0032] Example 5: The inner radius of the fillet 13 of the finite element model is 4.6 mm, and the fatigue service life is increased by 98% compared with the fatigue service life A.

[0033] Example 6: The inner radius of the fillet 13 of the finite element model is 4.7 mm, and the fatigue service life is increased by 81% compared with the fatigue service life A.

[0034] Example 7: The inner radius of the fillet 13 of the finite element model is 4.9 mm, and the fatigue service life is increased by 55% compared with the fatigue service life A.

[0035] Example 8: The inner radius of the fillet 13 of the finite element model is 5.0 mm, and the fatigue service life is increased by 46% compared with the fatigue service life A.

[0036] Example 9: The inner radius of the fillet 13 of the finite element model is 6.0 mm, and the fatigue service life is reduced compared to the fatigue service life A.

[0037] Therefore, based on the trend of the experimental results, it can be seen that when the inner corner radius is between 4.0mm and 4.5mm, the inner corner radius is directly proportional to the fatigue service life, while when the inner corner radius is above 4.5mm, the inner corner radius is inversely proportional to the fatigue service life.

[0038] This is because when the inner fillet radius is less than 4.0 mm, the stress concentration factor is high due to the small transition radius of the inner fillet, which reduces the fatigue service life. When the inner fillet radius reaches 6.0 mm, the thickness and rigidity of the fillet are too large, resulting in excessive stress concentration in the fillet 13, which also reduces the fatigue service life.

[0039] The finite element model with an inner fillet radius greater than 4.0 mm and less than 6.0 mm for the fillet portion 13 is the second finite element model, and its fatigue service life C is greater than both A and B.

[0040] like Figure 2-3 As shown, in this embodiment, further obtaining the fatigue life A of the original factory baffle corner plate specifically includes: The fatigue life of the original factory baffle corner plate conforms to the two-parameter Weibull distribution function. According to the formula Calculate , The fatigue life A of the original factory baffle corner plate, where, β Characteristic lifetime, , n This represents the sample size. N The fatigue life corresponding to each sample For shape parameters, S T For specimen coefficient, S C Here is the confidence coefficient. S R This represents the reliability coefficient.

[0041] It should be noted that a corner plate maintenance database was established based on corner plate C-inspection maintenance records since 2017 (intervals of 2-3 years) and EO (Engineering Order) special inspections since 2021 (intervals of 750 flight cycles). Fourteen sets of valid data were obtained within one C-inspection cycle, and two sets of valid data were obtained based on the EO special inspections (750 inspection cycles). It was found that the fatigue life of the original equipment manufacturer's baffle corner plates conforms to a two-parameter Weibull distribution function; therefore, fatigue life with 95% confidence and 95% reliability was calculated. Let A be the fatigue service life.

[0042] The original factory baffle corner plates are made of 2024-T42 aluminum alloy, therefore the shape parameters =4, specimen coefficient S T =1.0, confidence coefficient S C =1.32, reliability coefficientS R =1.0.

[0043] like Figure 2-3 As shown, in this embodiment, a first finite element model of the original factory baffle corner plate and the separate tooling 2 is further established, specifically including: A first finite element model of the original baffle door corner plate and the separate tooling 2 is established, so that the stress and strain values ​​of the crack region of the rounded corner 13 of the first finite element model converge under the mesh density.

[0044] It should be noted that, based on the geometric dimensions and curved surface shape of the original baffle corner plate, a CAD (Computer Aided Design) model of the corner plate structure was established, and a CAE (Computer Aided Engineering) model of the S4 element was drawn using finite element software.

[0045] Mesh convergence analysis was conducted on the region where the crack appeared in the corner plate 1 of the baffle gate. The stress and strain values ​​were calculated under mesh sizes of 3 mm, 2 mm, 1 mm, and 0.5 mm. When the mesh density reached about 1 mm, the stress and strain values ​​basically converged. When the mesh density reached 0.5 mm, the stress and strain values ​​converged. Finally, a mesh density of 0.5 mm was selected for finite element modeling.

[0046] The original baffle gate corner plate is equipped with strain gauges. A first finite element model is established for the original baffle gate corner plate, strain gauges, and separate fixture 2. The center bisection point of the bolt hole is the basic layout area. During the specific layout, the finite element mesh is appropriately offset by 6 to 7 finite element meshes towards the bending area to match the finite element coordinate system. To address the interference effect of the first set of circular arc transition areas, the strain gauges are placed at the connection point at 3 / 4 of the center of the bolt hole. This position is the stress concentration point and mesh deformation point during finite element analysis. These positions facilitate mechanical analysis, and the strain gauges must not interfere with the structure of the baffle gate corner plate 1 when they are installed.

[0047] In this embodiment, further, obtaining the displacement load M applied to the first finite element model when it reaches its fatigue service life A specifically includes: Obtain the average stress of the first finite element model under cyclic stress and strain under different displacement loads. and strain amplitude According to the formula Calculate fatigue service life N When fatigue service life N When the fatigue service life A is equal to the displacement load M, the corresponding displacement load is M, where... The fatigue strength coefficient, For elastic modulus, The fatigue strength index is related to the material. It is the fatigue ductility index. is the fatigue ductility coefficient of the material.

[0048] It should be noted that, considering the hysteresis phenomenon in metallic materials, the stress and strain values ​​of the displacement load need to be corrected to obtain stress-strain data under cyclic stress and strain, i.e., the average stress. and strain amplitude .

[0049] Elastic strain component: The elastic strain amplitude of the material under cyclic loading. According to Hooke's law, elastic strain is caused by stress amplitude, and the elastic strain amplitude is... Represented as: ,in, N This refers to the number of cycles (fatigue life). For elastic modulus, It is a material-related fatigue strength index, reflecting... The rate at which the cycle number changes.

[0050] Plastic strain component: Plastic strain amplitude With the fatigue ductility coefficient of the material and number of cycles N Related, the expression is , It is the fatigue ductility index, reflecting... The pattern of change with the number of iterations.

[0051] strain amplitude elastic strain amplitude With plastic strain amplitude The sum of, and when the average stress When ≠=0, a mean stress correction needs to be introduced, meaning that a mean stress exists. At that time, fatigue strength coefficient It will change; the corrected effective fatigue strength coefficient is: Therefore, strain amplitude .

[0052] The conventional mechanical properties of aluminum alloy 2024-T42, the static parameters used for single tensile plasticity analysis, and the relevant properties used for low-cycle fatigue analysis (failure cycles typically between 10⁴ and 10⁵) are shown in Table 1-3. UTS stands for Ultimate Tensile Strength.

[0053] Table 1. Conventional Mechanical Properties of Aluminum Alloy 2024-T42

[0054] Table 2 Static parameters of aluminum alloy 2024-T42

[0055] Table 3 Strain fatigue parameters of aluminum alloy 2024-T42

[0056] In this embodiment, the average stress of the first finite element model under different displacement loads is further obtained. and strain amplitude Specifically, it includes: According to the formula , and The local plastic deformation under different displacement loads was calculated. This leads to the corrected local maximum stress value. and local maximum strain value ,in, The effective stress concentration factor, This is the local maximum stress value before correction. It is the elastic modulus of the material. It is the strength coefficient. It is the strain hardening index; Obtain the minimum stress and minimum strain values ​​of the first finite element model without applied displacement load, and combine them with the local maximum stress value. and local maximum strain value The average stress of the first finite element model under different displacement loads was obtained. and strain amplitude .

[0057] It should be noted that since the loading condition of the baffle corner plate 1 is a reciprocating process of "loaded-unloaded", the minimum stress and minimum strain values ​​under no displacement load in the first finite element model are obtained, combined with the local maximum stress value. and local maximum strain value The average stress of the first finite element model under different displacement loads was obtained. and strain amplitude The corresponding displacement load M conforms to the actual working conditions. The minimum stress and minimum strain values ​​of the first finite element model without applied displacement load are calculated using the incremental Neuber formula set.

[0058] like Figure 2-4As shown, in this embodiment, the first sheet 11 and the second sheet 12 both extend along the first direction X, and the second sheet 12 and the first sheet 11 are arranged sequentially along the second direction Y. The first sheet 11 is bent toward the direction close to the second sheet 12 and forms a rounded corner 13. The separable fixture 2 includes a lower clamp 22 and an upper clamp 21 arranged sequentially along the second direction Y; the lower clamp 22 includes a lower fixing part 222 and a lower contact plate 221 connected sequentially along the second direction Y, the side of the lower contact plate 221 in the third direction Z matches the side of the second sheet 12 away from the first sheet 11 in the third direction Z, and the lower contact plate 221 extends along the first direction X; the upper clamp 21 includes an upper contact plate 212 and an upper loading part 211 connected sequentially along the second direction Y, the side of the upper contact plate 212 near the lower contact plate 221 in the second direction Y matches the side of the first sheet 11 away from the second sheet 12 in the second direction Y, and the upper contact plate 212 extends along the first direction X; Among them, the first direction X, the second direction Y, and the third direction Z intersect each other perpendicularly.

[0059] It should be noted that a fixed support constraint is set for the lower fixed part 222 of the lower clamp 22, and the upper loading end of the upper clamp 21 is coupled to the same RP (Reference Point), limiting the displacement in the first direction X and the third direction Z while applying a tensile force in the second direction Y. The connection between the baffle corner plate 1 and the separate tooling 2 is realized by using a Faster to simulate the bolt, and the Faster influence range is set to the bolt size. The loading method is based on the actual operating condition of the baffle, which is the influence of the reverse thrust airflow during aircraft landing, and a biaxial eccentric unidirectional tension method is used for loading.

[0060] To avoid localized failure caused by stress concentration, the thickness of the upper loading part 211, which has some areas of stress concentration, is adjusted to 5mm, while the remaining parts maintain a thickness of 3mm. A chamfer design is added to optimize the structural performance.

[0061] The side of the lower contact plate 221 in the third direction Z matches the side of the second sheet 12 in the third direction Z away from the first sheet 11. The side of the upper contact plate 212 in the second direction Y close to the lower contact plate 221 matches the side of the first sheet 11 in the second direction Y away from the second sheet 12. This allows for more sufficient force to be applied to the first sheet 11 and the second sheet 12, and more accurate calculation of the fatigue service life of the baffle corner plate 1.

[0062] The upper contact plate 212 has a width of 80mm, and the lower contact plate 221 has a width of 120mm.

[0063] The separable fixture 2 is made of S45C steel with an elastic modulus of 200 GPa and a Poisson's ratio of 0.3. Since only a conservative elastic analysis is performed during the simulation, no other mechanical property parameters are required.

[0064] like Figure 2 As shown, a baffle corner piece 1 according to an embodiment of the present invention is obtained by the above-mentioned design method of baffle corner piece 1, including: an integrally formed first sheet 11 and a second sheet 12, both the first sheet 11 and the second sheet 12 extending along a first direction X, the second sheet 12 and the first sheet 11 being arranged sequentially along a second direction Y, the first sheet 11 being bent toward the direction close to the second sheet 12 to form a rounded corner portion 13, the inner rounded corner radius of the rounded corner portion 13 being D, 4.0mm < D < 6.0mm; Among them, the first direction X and the second direction Y intersect each other perpendicularly.

[0065] It should be noted that the cracks in the one-piece molded baffle corner plate 1 mainly occur in the rounded corner portion 13. This invention can change the impact resistance of the overall baffle corner plate 1 by changing the inner radius of the rounded corner portion 13, thereby improving its fatigue service life. When the inner radius D of the rounded corner portion 13 is greater than 4.5mm and less than 6.0mm, the fatigue service life of the baffle corner plate 1 is improved compared to the original baffle corner plate, with a maximum improvement of 109%, which slows down the rate of crack formation. Applying this baffle corner plate 1 to the thrust reverser baffle of the engine nacelle can reduce the frequency of daily replacement or maintenance, thereby reducing economic losses.

[0066] like Figure 2 As shown, in this embodiment, the inner radius D of the rounded corner portion 13 is greater than 4.0 mm and less than 5.0 mm.

[0067] It should be noted that although the inner radius of the rounded corner portion 13 is between 5.0mm and 6.0mm, which can improve the fatigue life of the original baffle corner plate, it is easy to cause interference with other components of the baffle when installing the baffle corner plate 1. Therefore, the inner radius D of the rounded corner portion 13 is preferably greater than 4.0mm and less than 5.0mm.

[0068] like Figure 2 As shown, in this embodiment, the inner radius D of the rounded corner portion 13 is further 4.5 mm.

[0069] It should be noted that when the inner radius of the rounded corner 13 is 4.5mm, the fatigue service life of the original baffle corner plate is increased by 109%, which significantly improves the fatigue service life of the baffle corner plate 1.

[0070] like Figure 2As shown, in this embodiment, the first sheet 11 is provided with a plurality of first holes 111 that are evenly distributed along the first direction X, and the second sheet 12 is provided with a plurality of second holes 121 that are evenly distributed along the first direction X. The first holes 111 and the second holes 121 are arranged alternately.

[0071] It should be noted that the staggered arrangement of the first hole 111 and the second hole 121 avoids direct alignment of adjacent holes, disperses stress concentration, and reduces the risk of deformation and cracking. The first hole 111 is used to connect with a high-mounted bolt to connect the first sheet 11 to the baffle frame or guard plate, and the second hole 121 is used to connect with a rivet to connect the second sheet 12 to the baffle body.

[0072] Along the first direction X, the number of second holes 121 between two adjacent first holes 111 is preferably two. The diameter of the first holes 111 and the second holes 121 is preferably 4.06 mm to 4.17 mm, more preferably 4.0 mm.

[0073] The working process of this invention is as follows: by obtaining the fatigue service life A of the original factory baffle corner plate, a tensile test is performed on the original factory baffle corner plate and the separate tooling 2 after finite element modeling. The displacement load M required by the model to reach the fatigue service life A is obtained. Then, the actual original factory baffle corner plate is installed on the separate tooling 2 and the displacement load M is applied for a tensile test to obtain the fatigue service life B. When the difference between A and B is within the preset error range, it proves that the displacement load M obtained by the tensile test of finite element modeling can reflect the load situation of the baffle corner plate 1 in actual application.

[0074] By repeatedly adjusting the inner corner radius of the baffle plate 1 in the first finite element model, multiple second finite element models can be obtained. Tensile tests are performed on the multiple second finite element models under displacement load M to obtain fatigue service life. The second finite element model with a fatigue service life C that is greater than both A and B is selected. The fatigue service life of the baffle plate 1 corresponding to this second finite element model is improved compared with the original baffle plate.

[0075] In summary, the embodiments of the present invention provide a baffle gate corner piece and its design method, which can obtain a baffle gate corner piece with improved fatigue service life more quickly and accurately.

[0076] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A design method for a baffle door corner piece, the baffle door corner piece comprising a first sheet and a second sheet integrally formed and connected by rounded corner portions, characterized in that, The design method of the baffle gate corner plate includes the following steps: S1. Obtain the fatigue service life A of the original factory baffle corner plate; S2. Establish the first finite element model of the original factory baffle door corner piece and the separate tooling, perform a tensile test on the first finite element model, and obtain the displacement load M applied to the first finite element model when it reaches the fatigue service life A. S3. Install the original factory baffle corner plate on the separate tooling for tensile testing, and apply the displacement load M to the separate tooling to obtain the fatigue service life B of the original factory baffle corner plate. S4. When the difference between the fatigue service life A and the fatigue service life B is within the preset error range, the inner radius of the rounded corner of the first finite element model is adjusted to obtain the second finite element model. When the second finite element model is subjected to the displacement load M for tensile testing, the second finite element model has a fatigue service life C, and the baffle corner piece in the second finite element model is obtained. Where B > A, then C > B; and A > B, then C > A.

2. The design method of the baffle corner plate according to claim 1, characterized in that, The process of obtaining the fatigue life A of the original factory baffle corner plate specifically includes: The fatigue life of the original factory baffle door corner plate conforms to a two-parameter Weibull distribution function. According to the formula Calculate , Let A be the fatigue service life of the original factory baffle corner plate, where, β Characteristic lifetime, , n This represents the sample size. N The fatigue life corresponding to each sample For shape parameters, S T For specimen coefficient, S C Here is the confidence coefficient. S R This represents the reliability coefficient.

3. The design method of the baffle corner plate according to claim 1, characterized in that, The establishment of the first finite element model of the original factory baffle door corner plate and the separate tooling specifically includes: A first finite element model of the original baffle door corner plate and the separate tooling is established, so that the stress and strain values ​​of the rounded corner crack region of the first finite element model converge at the mesh density.

4. The design method of the baffle corner plate according to claim 1, characterized in that, The specific steps of obtaining the displacement load M applied to the first finite element model when it reaches the fatigue service life A include: Obtain the average stress of the first finite element model under cyclic stress and strain under different displacement loads. and strain amplitude According to the formula Calculate fatigue service life N When the fatigue service life N When the fatigue service life A is equal to the specified fatigue service life, the corresponding displacement load is the displacement load M, where, The fatigue strength coefficient, For elastic modulus, The fatigue strength index is related to the material. It is the fatigue ductility index. is the fatigue ductility coefficient of the material.

5. The design method of the baffle corner plate according to claim 1, characterized in that, The average stress of the first finite element model under different displacement loads is obtained. and strain amplitude Specifically, it includes: According to the formula , and The local plastic deformation under different displacement loads was calculated. This leads to the corrected local maximum stress value. and local maximum strain value ,in, The effective stress concentration factor, This is the local maximum stress value before correction. It is the elastic modulus of the material. It is the strength coefficient. It is the strain hardening index; Obtain the minimum stress and minimum strain values ​​of the first finite element model without applied displacement load, and combine them with the local maximum stress value. and local maximum strain value The average stress of the first finite element model under different displacement loads was obtained. and strain amplitude .

6. The design method of the baffle gate corner plate according to claim 1, characterized in that, Both the first sheet and the second sheet extend along a first direction, and the second sheet and the first sheet are arranged sequentially along a second direction. The first sheet is bent toward the direction close to the second sheet to form the rounded corner portion. The detachable tooling includes a lower clamp and an upper clamp arranged sequentially along a second direction; the lower clamp includes a lower fixing part and a lower contact plate connected sequentially along the second direction, the side of the lower contact plate in a third direction matches the side of the second sheet away from the first sheet in a third direction, and the lower contact plate extends along a first direction; the upper clamp includes an upper contact plate and an upper loading part connected sequentially along the second direction, the side of the upper contact plate near the lower contact plate in the second direction matches the side of the first sheet away from the second sheet in the second direction, and the upper contact plate extends along the first direction; The first direction, the second direction, and the third direction intersect each other perpendicularly.

7. A baffle gate corner plate, obtained by the design method of the baffle gate corner plate according to any one of claims 1-6, characterized in that, include: The first sheet and the second sheet are integrally formed. Both the first sheet and the second sheet extend along a first direction. The second sheet and the first sheet are arranged sequentially along a second direction. The first sheet is bent towards the second sheet to form a rounded corner. The inner radius of the rounded corner is D, which is 4.0 mm < D < 6.0 mm. The first direction and the second direction intersect each other perpendicularly.

8. The baffle corner plate according to claim 7, characterized in that, The inner radius D of the rounded corner is greater than 4.0 mm and less than 5.0 mm.

9. The baffle corner plate according to claim 7, characterized in that, The inner radius D of the rounded corner is 4.5mm.

10. The baffle corner plate according to claim 7, characterized in that, The first sheet has a plurality of first holes evenly distributed in sequence along a first direction, and the second sheet has a plurality of second holes evenly distributed in sequence along a first direction, with the first holes and the second holes arranged alternately.

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