Design method of birdshot geometry and birdshot

Abstract

The present invention relates to a design method of a birdshot geometric shape and a birdshot thereof, the design method of the birdshot geometric shape comprising the following steps: determining a bird to be simulated, measuring the maximum circumference of an adult bird in a first state and calculating the maximum diameter, the first state being the state of an adult bird with two wings naturally combined; measuring the lengths of various parts of the adult bird in the first state and calculating the trunk length; designing the geometric dimensions of the birdshot based on the maximum diameter and trunk length. The design method of the birdshot geometric shape provided in the present application is based on the morphological data of a real bird, the designed birdshot can be as close to the real morphology of the bird as possible, the birdshot has a high degree of authenticity, and can effectively provide the authenticity of the relevant bird strike test or bird strike simulation analysis results, thereby effectively improving the anti-bird strike capability of an aircraft or aircraft engine.

Description

Technical Field

[0001] The invention relates to the technical field of flight collision test, in particular to a design method for the geometric shape of a birdshot and the birdshot. Background Art

[0002] Bird strike test and bird strike finite element simulation analysis are key tasks that must be performed during the bird strike resistance design and airworthiness certification process for aircraft or aircraft engines. When conducting bird strike test or bird strike simulation analysis, the geometric shape of the bird projectile used for the test or simulation needs to be designed according to the morphology of the real bird body. The geometric shape of the bird projectile directly affects the results of the bird strike test and bird strike simulation analysis, and is a key input parameter for bird strike analysis related to aircraft or aircraft engines. Since cylinders, ellipsoids and capsules (middle cylinder plus two hemispheres) can better meet the morphological characteristics of the actual bird body flying during bird strikes, the above three simplified shapes are often used to design the geometry of bird projectiles when conducting bird strike analysis at home and abroad. However, the actual geometric dimensions of the real bird body are generally not fully considered during the design, but some conventional practices are simply used to design the geometry of the bird projectile.

[0003] At present, when designing the shape of cylindrical, ellipsoidal and capsule birdshot, the shape design of the above three shapes of birdshot is basically carried out in the way of length-to-diameter 2:1. For example, the research papers "The Influence of Bird Body Shape on the Dynamic Response of Bird Strike on Aircraft Windshield", "Simulation Research on Bird Body Mechanical Model" and "Research on Simulated Birdshot for Bird Strike Test" all use the above method to construct the geometric shape of birdshot. However, the length-to-diameter ratio of 2:1 cannot represent the morphological characteristics of all birds. Most of the length-to-diameter ratios of real birds do not conform to the assumption of 2:1. Therefore, the length-to-diameter ratio of 2:1 is not universal. Using this as the basis for the geometric shape design of the three birdshots (cylinder, ellipsoid and capsule) cannot well reflect the specific morphology of the real bird. This design method results in the birdshot being unable to effectively reflect the actual geometric morphological characteristics of the bird, and the industry has not yet formed a birdshot geometric shape engineering design method that can more realistically reflect the actual bird morphology.

[0004] When designing the geometric shape of a bird, it is necessary to combine the specific geometric shape of the real bird. However, the current existing technology lacks consideration of the real geometric shape of the bird when designing the geometric shapes of the three types of bird bombs, and cannot effectively simulate the geometric shape of the real bird, which greatly reduces the authenticity of the relevant bird strike test or bird strike simulation analysis results. Summary of the invention

[0005] Based on this, it is necessary to provide a birdshot geometry design method and its birdshot to address the problem that the bird strike test is distorted due to the inability to truly simulate the bird's body shape when designing the birdshot geometry.

[0006] A method for designing the geometric shape of a birdshot comprises the following steps:

[0007] Determine a bird to be simulated, measure the maximum circumference of an adult bird of the bird in a first state and calculate the maximum diameter, wherein the first state is a state of the adult bird with both wings naturally folded;

[0008] measuring the lengths of various parts of the adult bird in the first state, and calculating the trunk length;

[0009] The geometric dimensions of the birdshot are designed based on the maximum diameter and the trunk length.

[0010] Furthermore, the lengths of the various parts include the whole body length of the bird, the peak length of the bird's beak and the tail length of the bird.

[0011] Furthermore, the trunk length is the whole body length of the bird minus the beak length of the bird and the tail length of the bird.

[0012] Furthermore, the geometric dimensions include a length in a first direction and a cross-sectional dimension in a second direction, the first direction is perpendicular to the second direction, the length in the first direction is the trunk length, the cross-section in the second direction is an arc surface, and the largest diameter of the arc surface is the maximum diameter.

[0013] Furthermore, the birdshot is a cylindrical birdshot, the maximum diameter is the diameter of the cylindrical birdshot, and the trunk length is the length of the cylindrical birdshot.

[0014] Furthermore, the birdshot is a capsule birdshot, the maximum diameter is the diameter of the end hemisphere of the capsule birdshot, and the trunk length is the length of the capsule birdshot.

[0015] Furthermore, the birdshot is an ellipsoidal birdshot, the maximum diameter is the short axis of the ellipsoidal birdshot, and the trunk length is the long axis of the ellipsoidal birdshot.

[0016] Furthermore, a birdshot is provided, which is completed by using the above-mentioned design method of the birdshot geometric shape, comprising:

[0017] A longitudinal cross section, wherein the longitudinal cross section comprises a plurality of arc surfaces arranged along a first direction, the areas of the arc surfaces are equal or unequal along the first direction, and the diameter of the largest arc surface is the maximum diameter of the adult bird body in the first state;

[0018] A transverse cross section includes a rectangular surface or an arcuate surface arranged along a second direction, the second direction is perpendicular to the first direction, and the maximum length of the rectangular surface or the arcuate surface is the trunk length of the adult bird.

[0019] Furthermore, the area of ​​the arc surface gradually shrinks toward both ends along the first direction.

[0020] Furthermore, the birdshot is made of gelatin.

[0021] The design method of the geometric shape of the birdshot provided in the present application is that the tester first determines the type of bird to be simulated, measures the maximum circumference of the adult bird of the bird in the state of natural merging of the wings, calculates the maximum diameter, and measures the trunk length of the adult bird in the state of natural merging of the wings, and determines the geometric size of the birdshot from the maximum diameter and the trunk length. The design method of the geometric shape of the birdshot provided in the present application is based on the morphological data of the real bird, and the designed birdshot can be as close to the real morphology of the bird as possible, and the birdshot has high authenticity, which can effectively provide the authenticity of the relevant bird strike test or bird strike simulation analysis results, thereby effectively improving the anti-bird strike capability of the aircraft or aircraft engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A flow chart of a method for designing the geometric shape of a birdshot according to an embodiment of the present application;

[0023] Figure 2A A schematic diagram of the maximum diameter and total body length of an adult bird according to a method for designing the geometric shape of a birdshot according to an embodiment of the present application;

[0024] Figure 2B A schematic diagram of measuring the beak length of an adult bird according to a method for designing the geometric shape of a birdshot according to an embodiment of the present application;

[0025] Figure 2C A schematic diagram of measuring the tail length of an adult bird according to a method for designing the geometric shape of a birdshot according to an embodiment of the present application;

[0026] Figure 3A A schematic diagram of the geometric dimensions of a cylindrical birdshot according to a method for designing the geometric shape of a birdshot according to an embodiment of the present application;

[0027] Figure 3B A schematic diagram of geometric dimensions of a capsule birdshot according to a method for designing the geometric shape of a birdshot according to an embodiment of the present application;

[0028] Figure 3C A schematic diagram of geometric dimensions of an ellipsoidal birdshot according to a method for designing the geometric shape of a birdshot according to an embodiment of the present application;

[0029] Among them, L is the total length of the bird, L1 is the trunk length of the bird, L2 is the beak length of the bird, L3 is the tail length of the bird, C is the maximum circumference of the bird, and D is the maximum diameter;

[0030] AA, first direction, BB, second direction. DETAILED DESCRIPTION

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0032] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like 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 present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0033] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0034] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0036] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0037] Bird strike test and bird strike finite element simulation analysis are key tasks that must be performed during the bird strike resistance design and airworthiness certification process for aircraft or aircraft engines. When conducting bird strike test or bird strike simulation analysis, the geometric shape of the bird projectile used for the test or simulation needs to be designed according to the morphology of the real bird body. The geometric shape of the bird projectile directly affects the results of the bird strike test and bird strike simulation analysis, and is a key input parameter for bird strike analysis related to aircraft or aircraft engines. Since cylinders, ellipsoids and capsules (middle cylinder plus two hemispheres) can better meet the morphological characteristics of the actual bird body flying during bird strikes, the above three simplified shapes are often used to design the geometry of bird projectiles when conducting bird strike analysis at home and abroad. However, the actual geometric dimensions of the real bird body are generally not fully considered during the design, but some conventional practices are simply used to design the geometry of the bird projectile.

[0038] At present, when designing the shape of cylindrical, ellipsoidal and capsule birdshot, the above three shapes of birdshot are basically designed in the way of length-to-diameter 2:1. However, the length-to-diameter ratio of 2:1 cannot represent the morphological characteristics of all bird bodies. Most of the length-to-diameter ratios of real bird bodies do not conform to the assumption of 2:1. Therefore, the length-to-diameter ratio of 2:1 is not universal. Using this as the basis for the geometric shape design of the three birdshots (cylinder, ellipsoid and capsule) cannot well reflect the specific morphology of real bird bodies. This design method causes the birdshot to be unable to effectively reflect the actual geometric morphological characteristics of the bird body. The industry has not yet formed a birdshot geometric shape engineering design method that can more realistically reflect the actual bird body morphology.

[0039] The present application provides a method for designing the geometric shape of a birdshot, specifically, Figure 1 The flow chart of the method for designing the geometric shape of a birdshot according to an embodiment of the present application shown includes the following steps:

[0040] S1: Determine a bird to be simulated, measure the maximum circumference of an adult bird in a first state and calculate the maximum diameter, wherein the first state is a state of the adult bird with both wings naturally fused together;

[0041] When conducting bird strike tests, since there are many types of birds and their activity areas are different, the impact force on the aircraft when a collision occurs in different environments is also different. Therefore, before the test, the experimenter can first determine the birds that need to be simulated according to their test needs, such as listing several common birds in the area in each season, and then measuring the maximum circumference of the adult bird of this bird in the first state.

[0042] Adult birds are chosen for measurement because they are more stable in shape and heavier than juvenile birds, and thus produce greater impact force. The first state described here refers to the state of an adult bird with its wings naturally fused together. This state is chosen as the test benchmark. On the one hand, it is convenient to unify all birds in one state, so that their sizes can be measured more accurately. On the other hand, assuming that when a bird hits an airplane, the smaller the space occupied by its body at the moment of impact, the greater the impact force. Therefore, when designing bird bombs, choosing the state of an adult bird with its wings naturally fused together for measurement can be as close as possible to the actual impact situation.

[0043] When measuring the circumference of a bird, you can measure the circumference of each part of the bird from the head to the tail. When measuring, you can lay the bird flat, and measure the circumference of each part of the bird from front to back with the line connecting the head and tail as the axis and record them one by one. Finally, choose the maximum circumference. Through statistical analysis, it can be seen that under normal circumstances, the maximum circumference of an adult bird is at the abdominal cavity of the bird. Assuming that the maximum circumference obtained after measurement is C, according to the circumference formula, the maximum diameter D = C / π. The specific measurement method can be seen in Figure 2A A schematic diagram of measuring the maximum diameter of an adult bird body is shown in a method for designing the geometric shape of a birdshot according to an embodiment of the present application.

[0044] This application conducts a survey on bird groups that often appear in the use area and selects the mountain sparrow as the experimental type. After measurement, the maximum circumference of the trunk (including head and neck) of an adult mountain sparrow when its wings are naturally combined is C = 110mm. The diameter of the mountain sparrow's trunk at the maximum circumference is D = C / π = 110mm / 3.14 = 35mm.

[0045] S2: measuring the lengths of various parts of the adult bird in the first state, and calculating the trunk length;

[0046] Furthermore, the lengths of various parts of the adult bird's body are still measured with the wings naturally folded together, and the trunk length is calculated. It should be noted that the experimenter can also directly measure to obtain the bird's trunk length, but in order to reduce the measurement error, it is recommended that the experimenter measure the length of various parts of the bird's body in turn, including the bird's whole body length, the bird's beak length and the bird's tail length. The experimenter measures the bird's whole body length in turn and records it as L, the bird's beak length as L2, and the bird's tail length as L3. The bird's trunk length L1 = L-L2-L3 can be deduced. For details, see Figure 2A-2C Schematic diagram of length measurement of various parts of the bird's body is shown.

[0047] Taking the mountain sparrow as an example, the total length of the body of an adult mountain sparrow with its wings naturally combined is L = 136 mm, the peak length of the beak is L2 = 11.3 mm, and the tail length is L3 = 49.2 mm. The trunk length L1 of the mountain sparrow is calculated to be:

[0048] L1=L-L2-L3=136mm-11.3mm-49.2mm=75.5mm

[0049] S3: Design the geometric dimensions of the birdshot based on the maximum diameter and the trunk length.

[0050] When designing birdshot, in order to be as close as possible to the actual bird body, the aspect ratio is usually used for design, that is, the value after the length and diameter are compared. At present, the common birdshot is designed with an aspect ratio of 2:1. Although the design is relatively simple, it cannot truly reflect the size of the bird body, which leads to a large error in the impact test. After determining the maximum diameter D and the trunk length L1, the size of birdshot with different structures is set according to the maximum diameter D and the trunk length L1, including but not limited to cylindrical birdshot, capsule birdshot and ellipsoidal birdshot.

[0051] Furthermore, the geometric dimensions of the birdshot are designed according to different types of birdshot, and the geometric dimensions include the length in the first direction AA and the cross-sectional dimension in the second direction BB, and the first direction AA is perpendicular to the second direction BB. Specifically, referring to the structure of the bird body, the length of the birdshot in the first direction AA is equivalent to the trunk length L1 of the bird body, and the cross-sectional dimension of the birdshot in the second direction BB is equivalent to the maximum circumferential area of ​​the bird body. Therefore, the length in the first direction AA can be set as the trunk length L1, and the cross-sectional dimension in the second direction BB is an arc surface, and the largest arc surface diameter is the maximum diameter D.

[0052] According to the three common types of birdshot, the shape structure of the birdshot can be set to cylindrical birdshot, capsule birdshot and ellipsoidal birdshot. For details, refer to Figure 3A-3C Schematic diagram of the geometric dimensions of the three types of birdshot described in.

[0053] When the structure of the birdshot is a cylindrical birdshot, the maximum diameter D is the diameter of the cylindrical birdshot, and the trunk length L1 is the length of the cylindrical birdshot.

[0054] Taking the mountain sparrow as an example, the diameter of the cylindrical birdshot is D = 35 mm and the length is L1 = 75.5 mm.

[0055] When the structure of the birdshot is a capsule birdshot, the maximum diameter D is the diameter of the end hemisphere of the capsule birdshot, and the trunk length L1 is the length of the capsule birdshot.

[0056] Taking the mountain sparrow as an example, the diameter D of the end hemisphere of the capsule birdshot is 35 mm, and the length L1 is 75.5 mm.

[0057] When the structure of the birdshot is an ellipsoidal birdshot, the maximum diameter D is the short axis of the ellipsoidal birdshot, and the trunk length L1 is the long axis of the ellipsoidal birdshot.

[0058] Taking the mountain sparrow as an example, the short axis D of the ellipsoidal birdshot is 35 mm, and the long axis L1 is 75.5 mm.

[0059] The present application proposes a specific geometric shape design method for birdshot shapes of three shapes: cylinder, ellipsoid and capsule (middle cylinder plus hemispheres at both ends), based on full consideration of the geometric morphology of real bird bodies. The present application can solve the problem that the currently commonly used birdshot shape design methods lack consideration of the real bird body morphology. The birdshot designed according to the present application can effectively simulate the morphology of real bird bodies, improve the authenticity of related bird strike tests and bird strike simulation analysis results, and thus enhance the anti-bird strike capability of aircraft or aircraft engines.

[0060] The design method of the geometric shape of the birdshot provided in the present application is that the tester first determines the type of bird to be simulated, measures the maximum circumference of the adult bird of the bird in the state of natural merging of the wings, calculates the maximum diameter, and measures the trunk length of the adult bird in the state of natural merging of the wings, and determines the geometric size of the birdshot from the maximum diameter and the trunk length. The design method of the geometric shape of the birdshot provided in the present application is based on the morphological data of the real bird, and the designed birdshot can be as close to the real morphology of the bird as possible, and the birdshot has high authenticity, which can effectively provide the authenticity of the relevant bird strike test or bird strike simulation analysis results, thereby effectively improving the anti-bird strike capability of the aircraft or aircraft engine.

[0061] Furthermore, the present application provides a birdshot, which is completed by using the above-mentioned birdshot geometric shape design method, including:

[0062] Longitudinal section, i.e. Figure 3A-3C The longitudinal cross section includes a plurality of arc surfaces arranged along a first direction AA, the areas of the arc surfaces being equal or unequal along the first direction AA, and the diameter of the largest arc surface being the maximum diameter D of the adult bird in the first state. When the birdshot structure adopts a cylindrical structure, the areas of the arc surfaces are equal along the first direction AA, and when the birdshot structure is an ellipsoid or a capsule, the areas of the arc surfaces are unequal along the first direction AA.

[0063] Transverse section, i.e. Figure 3A-3C The cross section includes a rectangular surface or an arc surface arranged along a second direction BB, the second direction BB is perpendicular to the first direction AA, and the maximum length of the rectangular surface or the arc surface is the trunk length L1 of the adult bird. That is, when the birdshot structure adopts a cylindrical structure, the cross section is a rectangular surface, and when the birdshot structure is an ellipsoid or a capsule, the cross section is an arc surface.

[0064] Furthermore, the area of ​​the arc surface gradually shrinks toward both ends along the first direction AA. In this case, the birdshot structure is an ellipsoid or capsule structure.

[0065] Furthermore, the birdshot is made of gelatin, which can simulate biological organisms as closely as possible in terms of material, and is closer to real birds in terms of volume and mass, thereby improving the accuracy of the impact test.

[0066] The bird eggs provided in the present application are obtained through a simulation design method, and can fit the shape of an existing bird body to the greatest extent possible, with a high biological similarity. Therefore, when conducting an aircraft collision test, the bird eggs using this structure can fit the actual bird collision scenario to the greatest extent possible, and the obtained test data is more authentic and reliable, which can effectively improve the authenticity of the bird strike test or bird strike simulation analysis results and enhance the aircraft's anti-bird strike capability.

[0067] The birdshot geometry design method provided in the present application is based on the morphological data of real birds. The technical path of the present application can be used to design three birdshot geometry shapes of different birds. The designed birdshot shapes have high authenticity and can effectively improve the authenticity of related bird strike tests or bird strike simulation analysis results, thereby effectively improving the anti-bird strike capability of aircraft or aircraft engines.

[0068] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for designing the geometric shape of a birdshot, characterized in that: The following steps are involved: Determine a bird to be simulated, measure the maximum circumference of an adult bird of the bird in a first state and calculate the maximum diameter, wherein the first state is a state of the adult bird with both wings naturally folded; Measure the lengths of various parts of the adult bird in the first state, and calculate the trunk length; the lengths of various parts include the whole body length of the adult bird, the peak length of the beak of the adult bird, and the tail length of the adult bird; the trunk length is the whole body length of the adult bird minus the peak length of the beak of the adult bird and the tail length of the adult bird; Designing the geometric dimensions of the birdshot based on the maximum diameter and the trunk length; Among them, the geometric dimensions include a length in a first direction and a cross-sectional dimension in a second direction, the first direction is perpendicular to the second direction, the length in the first direction is the trunk length, the cross-section in the second direction is an arc surface, and the largest diameter of the arc surface is the maximum diameter.

2. The method for designing the geometric shape of a birdshot according to claim 1, characterized in that: The birdshot is a cylindrical birdshot, the maximum diameter is the diameter of the cylindrical birdshot, and the trunk length is the length of the cylindrical birdshot.

3. The method for designing the geometric shape of a birdshot according to claim 1, characterized in that: The birdshot is a capsule birdshot, the maximum diameter is the diameter of the end hemisphere of the capsule birdshot, and the trunk length is the length of the capsule birdshot.

4. The method for designing the geometric shape of a birdshot according to claim 1, characterized in that: The birdshot is an ellipsoidal birdshot, the maximum diameter is the short axis of the ellipsoidal birdshot, and the trunk length is the long axis of the ellipsoidal birdshot.

5. A birdshot, produced by the method for designing the geometric shape of a birdshot according to claim 1, characterized in that: include: A longitudinal cross section, wherein the longitudinal cross section comprises a plurality of arc surfaces arranged along a first direction, the areas of the arc surfaces are equal or unequal along the first direction, and the diameter of the largest arc surface is the maximum diameter of the adult bird body in the first state; A transverse cross section includes a rectangular surface or an arcuate surface arranged along a second direction, the second direction is perpendicular to the first direction, and the maximum length of the rectangular surface or the arcuate surface is the trunk length of the adult bird.

6. The birdshot according to claim 5, characterized in that The area of ​​the arc surface gradually shrinks toward both ends along the first direction.

7. The birdshot according to claim 5, characterized in that The birdshot is made of gelatin.

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