Helicopter fuselage flight load distribution method and device

Abstract

The invention provides a helicopter fuselage flight load distribution method and device. The method comprises the steps that S1, a preset fuselage flight load resultant force F, an attack angle and a sideslip angle are obtained; s2, according to a preset attack angle and a preset sideslip angle, determining respective corresponding initial skin resultant forces of the skin of each region of the helicopter fuselage under the preset attack angle alpha and sideslip angle beta values in the initial skin resultant force matrix; and S3, according to the fuselage flight load resultant force F and the initial skin resultant force of the skin of each region of the helicopter fuselage, a load distribution result is obtained, and the load distribution result is used for helicopter fuselage frame beam strength checking. The distribution mode of distributing the helicopter fuselage flight load to different frame beam loads can be determined, and a design basis can be provided for helicopter frame beam structure design and strength check; according to the helicopter fuselage flight load distribution mode, a flight load distribution area division mode is determined, different frame beam load differences in different flight states are considered, and a resultant force matrix of different skin areas is established.

Description

Technical Field

[0001] The present application belongs to the technical field of helicopter aerodynamic load analysis, and in particular, relates to a method and device for distributing flight loads on a helicopter fuselage. Background Art

[0002] Helicopter fuselage flight loads are the severe aerodynamic loads that may be generated when the helicopter interacts with the air during flight.

[0003] The results of helicopter fuselage flight load analysis are the basis for the helicopter frame beam structure design and strength verification; the aerodynamic loads directly borne by the fuselage in the "Helicopter Load Manual" (Aviation Industry Press, 1991, ISBN: 7-80046-336-2) are used for local structural strength design, but are not considered for the overall strength design of the fuselage, which is difficult to meet the design requirements of new helicopters. Summary of the invention

[0004] The present invention proposes a helicopter fuselage flight load distribution method and device based on the fuselage flight load and taking into account the difference in frame beam loads under different flight states.

[0005] In one aspect, the present invention provides a method for distributing flight loads on a helicopter fuselage, comprising:

[0006] S1, obtaining the preset fuselage flight load resultant force F, angle of attack and sideslip angle;

[0007] S2. According to the preset angle of attack and sideslip angle, the initial skin resultant force corresponding to each region of the helicopter fuselage skin at the preset angle of attack α and sideslip angle β is determined in the initial skin resultant force matrix;

[0008] S3. According to the resultant force F of the fuselage flight load and the initial skin resultant force of each area of ​​the helicopter fuselage, a load distribution result is obtained, and the load distribution result is used for the strength check of the helicopter fuselage frame beam.

[0009] Optionally, the method further includes:

[0010] Step 1: Obtain the values ​​of the angle of attack and sideslip angle in the flight state corresponding to all flight loads of the helicopter fuselage;

[0011] Step 2: Use computational fluid dynamics (CFD) software to obtain the resultant force Fα of the skin of each area of ​​the helicopter fuselage at different angles of attack when the helicopter flight speed is Vmax and the sideslip angle is 0°; obtain the resultant force Fβ of the skin of each area of ​​the helicopter fuselage at different sideslip angles when the helicopter flight speed is Vmax and the angle of attack is 0°;

[0012] Step 3: According to the resultant force Fα and resultant force Fβ of the skin in each area of ​​the helicopter fuselage, the initial skin resultant force corresponding to the skin in each area of ​​the helicopter fuselage at different attack angles α and sideslip angles β is obtained to obtain the initial skin resultant force matrix.

[0013] Optionally, the initial skin force Fαβ=Fα+Fβ-F0; wherein F0 is the resultant force when the angle of attack and the sideslip angle are both 0°.

[0014] Optionally, after obtaining the resultant force Fα and the resultant force Fβ of the skin of each area of ​​the helicopter fuselage, the method further includes:

[0015] According to the results of helicopter fuselage force measurement wind tunnel test, the resultant force Fα and resultant force Fβ of the skin in each area of ​​the helicopter fuselage are corrected.

[0016] Optionally, the skin of each area of ​​the helicopter fuselage is divided according to frame beams.

[0017] Another aspect of the present invention further provides a helicopter fuselage flight load distribution device, comprising:

[0018] A parameter acquisition module is used to obtain the preset fuselage flight load resultant force F, angle of attack and sideslip angle;

[0019] An initial reasonable acquisition module is used to determine the initial skin resultant forces corresponding to the skins of various regions of the helicopter fuselage at the preset angle of attack α and sideslip angle β in the initial skin resultant force matrix according to the preset angle of attack and sideslip angle;

[0020] The distribution module is used to obtain the load distribution result according to the fuselage flight load resultant force F and the initial skin resultant force of each area of ​​the helicopter fuselage. The load distribution result is used for the strength check of the helicopter fuselage frame beam.

[0021] Optionally, the helicopter fuselage flight load distribution device further comprises:

[0022] Step 1: Obtain the values ​​of the angle of attack and sideslip angle in the flight state corresponding to all flight loads of the helicopter fuselage;

[0023] Step 2: Use computational fluid dynamics (CFD) software to obtain the resultant force Fα of the skin of each area of ​​the helicopter fuselage at different angles of attack when the helicopter flight speed is Vmax and the sideslip angle is 0°; obtain the resultant force Fβ of the skin of each area of ​​the helicopter fuselage at different sideslip angles when the helicopter flight speed is Vmax and the angle of attack is 0°;

[0024] Step 3: According to the resultant force Fα and resultant force Fβ of the skin in each area of ​​the helicopter fuselage, the initial skin resultant force corresponding to the skin in each area of ​​the helicopter fuselage at different attack angles α and sideslip angles β is obtained to obtain the initial skin resultant force matrix.

[0025] Optionally, the initial skin force Fαβ=Fα+Fβ-F0; wherein F0 is the resultant force when the angle of attack and the sideslip angle are both 0°.

[0026] Optionally, the helicopter fuselage flight load distribution device further comprises:

[0027] The correction module is used to correct the resultant force Fα and the resultant force Fβ of the skin of each area of ​​the helicopter fuselage according to the result of the helicopter fuselage force measurement wind tunnel test after obtaining the resultant force Fα and the resultant force Fβ of the skin of each area of ​​the helicopter fuselage.

[0028] Optionally, the skin of each area of ​​the helicopter fuselage is divided according to frame beams.

[0029] The present invention provides a method and device for distributing the flight load of a helicopter fuselage. In order to use the aerodynamic load directly borne by the fuselage for the overall strength design of the fuselage and solve the problem of the flight load distribution of the helicopter fuselage, for the first time, based on the flight load of the helicopter fuselage, by establishing a corresponding matrix of the aerodynamic load of the fuselage, considering the difference in different frame beam loads under different flight states, a method and process for determining the distribution mode of the fuselage flight load to different frame beam loads are given. The design method and process described in this application should include the flight load, sideslip angle and angle of attack of the helicopter fuselage. The design process described in this application can determine the distribution mode of the fuselage flight load to different frame beam loads, and the obtained different frame beam loads can be used for the design and strength verification of the helicopter frame beam structure. The present invention can determine the distribution mode of the helicopter fuselage flight load to different frame beam loads, and can provide a design basis for the design and strength verification of the helicopter frame beam structure; the helicopter fuselage flight load distribution mode determines a flight load distribution area division mode, considering the difference in different frame beam loads under different flight states, and establishes the resultant matrix of different skin areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The present invention is a schematic flow chart of the method for distributing the helicopter fuselage flight load. DETAILED DESCRIPTION

[0031] The specific contents of the technical solution provided by the present invention are introduced below in conjunction with the accompanying drawings.

[0032] like Figure 1 As shown, the present invention provides a method for distributing flight loads on a helicopter fuselage, comprising:

[0033] S1, obtaining the preset fuselage flight load resultant force F, angle of attack and sideslip angle;

[0034] S2. According to the preset angle of attack and sideslip angle, the initial skin resultant force corresponding to each region of the helicopter fuselage skin at the preset angle of attack α and sideslip angle β is determined in the initial skin resultant force matrix;

[0035] S3. According to the resultant force F of the fuselage flight load and the initial skin resultant force of each area of ​​the helicopter fuselage, a load distribution result is obtained, and the load distribution result is used for the strength check of the helicopter fuselage frame beam.

[0036] Optionally, the method further includes:

[0037] Step 1: Obtain the values ​​of the angle of attack and sideslip angle in the flight state corresponding to all flight loads of the helicopter fuselage;

[0038] Step 2: Use computational fluid dynamics (CFD) software to obtain the resultant force Fα of the skin of each area of ​​the helicopter fuselage at different angles of attack when the helicopter flight speed is Vmax and the sideslip angle is 0°; obtain the resultant force Fβ of the skin of each area of ​​the helicopter fuselage at different sideslip angles when the helicopter flight speed is Vmax and the angle of attack is 0°;

[0039] Step 3: According to the resultant force Fα and resultant force Fβ of the skin in each area of ​​the helicopter fuselage, the initial skin resultant force corresponding to the skin in each area of ​​the helicopter fuselage at different attack angles α and sideslip angles β is obtained to obtain the initial skin resultant force matrix.

[0040] Optionally, the initial skin force Fαβ=Fα+Fβ-F0; wherein F0 is the resultant force when the angle of attack and the sideslip angle are both 0°.

[0041] Optionally, after obtaining the resultant force Fα and the resultant force Fβ of the skin of each area of ​​the helicopter fuselage, the method further includes:

[0042] According to the results of helicopter fuselage force measurement wind tunnel test, the resultant force Fα and resultant force Fβ of the skin in each area of ​​the helicopter fuselage are corrected.

[0043] Optionally, the skin of each area of ​​the helicopter fuselage is divided according to frame beams.

[0044] Another aspect of the present invention further provides a helicopter fuselage flight load distribution device, comprising:

[0045] A parameter acquisition module is used to obtain the preset fuselage flight load resultant force F, angle of attack and sideslip angle;

[0046] An initial reasonable acquisition module is used to determine the initial skin resultant forces corresponding to the skins of various regions of the helicopter fuselage at the preset angle of attack α and sideslip angle β in the initial skin resultant force matrix according to the preset angle of attack and sideslip angle;

[0047] The distribution module is used to obtain the load distribution result according to the fuselage flight load resultant force F and the initial skin resultant force of each area of ​​the helicopter fuselage. The load distribution result is used for the strength check of the helicopter fuselage frame beam.

[0048] Optionally, the helicopter fuselage flight load distribution device further comprises:

[0049] Step 1: Obtain the values ​​of the angle of attack and sideslip angle in the flight state corresponding to all flight loads of the helicopter fuselage;

[0050] Step 2: Use computational fluid dynamics (CFD) software to obtain the resultant force Fα of the skin of each area of ​​the helicopter fuselage at different angles of attack when the helicopter flight speed is Vmax and the sideslip angle is 0°; obtain the resultant force Fβ of the skin of each area of ​​the helicopter fuselage at different sideslip angles when the helicopter flight speed is Vmax and the angle of attack is 0°;

[0051] Step 3: According to the resultant force Fα and resultant force Fβ of the skin in each area of ​​the helicopter fuselage, the initial skin resultant force corresponding to the skin in each area of ​​the helicopter fuselage at different attack angles α and sideslip angles β is obtained to obtain the initial skin resultant force matrix.

[0052] Optionally, the initial skin force Fαβ=Fα+Fβ-F0; wherein F0 is the resultant force when the angle of attack and the sideslip angle are both 0°.

[0053] Optionally, the helicopter fuselage flight load distribution device further comprises:

[0054] The correction module is used to correct the resultant force Fα and the resultant force Fβ of the skin of each area of ​​the helicopter fuselage according to the result of the helicopter fuselage force measurement wind tunnel test after obtaining the resultant force Fα and the resultant force Fβ of the skin of each area of ​​the helicopter fuselage.

[0055] Optionally, the skin of each area of ​​the helicopter fuselage is divided according to frame beams.

[0056] Exemplarily, in a specific embodiment of the present invention, a method for distributing flight loads on a helicopter fuselage comprises the following steps:

[0057] Step S1-1: Different flight loads of the helicopter fuselage correspond to different flight states. The angle of attack in the flight state is taken. After the angles of attack corresponding to all flight loads are taken out, the minimum value of all corresponding angles of attack is taken as αmin of the subsequent calculation state, and the maximum value of all corresponding angles of attack is taken as αmax of the subsequent calculation state;

[0058] Step S1-2: Different flight loads of the helicopter fuselage correspond to different flight states. The sideslip angle in the flight state is taken. After the sideslip angles corresponding to all flight loads are taken out, the minimum value of all corresponding sideslip angles is taken as βmin of the subsequent calculation state, and the maximum value of all corresponding sideslip angles is taken as βmax of the subsequent calculation state.

[0059] Step S2-1: the fuselage surface skin is divided according to the frame beam, and different skin areas are numbered 1, 2, ..., N. Computational fluid dynamics (CFD) software is used to calculate the following conditions: flight speed Vmax, sideslip angle 0°, angle of attack range αmin~αmax, and obtain the resultant force Fα corresponding to the skin of different divided areas at different angles of attack α;

[0060] Step S2-2: Divide the fuselage surface skin into the frame beam in the same way as in step S2, and use computational fluid dynamics (CFD) software to calculate the following conditions: flight speed Vmax, angle of attack 0°, sideslip angle range βmin~βmax, and obtain the resultant force Fβ corresponding to the skin in different divided areas at different sideslip angles β, and the resultant force F0 corresponding to the sideslip angle of 0°;

[0061] For example, after the resultant force is obtained, it is also necessary to correct the resultant force Fα and the resultant force Fβ of the skin of each area of ​​the helicopter fuselage according to the results of the helicopter fuselage force measurement wind tunnel test.

[0062] For example, the resultant force Fα of the skin in each area at different angles of attack is combined into the resultant force Ftotalα of the fuselage at different angles of attack, and the curve of Ftotalα versus α is plotted, and the curve of the resultant force of the fuselage in the fuselage force measurement wind tunnel test versus the angle of attack is plotted, and the two curves are compared to remove the fuselage resultant force points with large differences, and the adjacent Ftotalα is used for fitting correction. The same method is used for different sideslip angles.

[0063] Step S2-3: Under different angles of attack α and sideslip angles β, calculate the skin force Fαβ=Fα+Fβ-F0 in different divided areas, and record the skin force numbered N as F N αβ, we can get the matrix [F1αβ,F2αβ,……,F N αβ];

[0064] Step S3: Multiply the resultant force F of the fuselage flight load by the matrix [F1αβ, F2αβ, ..., F N αβ], and obtain the flight load FN on the skins with different numbers N.

[0065] This paper provides a method for establishing the resultant force matrix of different skin areas, and gives a method and process for determining the distribution of fuselage flight loads to different frame beam loads, which can be used for the design and strength verification of helicopter frame beam structures.

Claims

1. A method for distributing flight loads on a helicopter fuselage, characterized in that: include: S1, obtaining the preset fuselage flight load resultant force F, angle of attack and sideslip angle; S2. According to the preset angle of attack and sideslip angle, the initial skin resultant force corresponding to each region of the helicopter fuselage skin at the preset angle of attack α and sideslip angle β is determined in the initial skin resultant force matrix; S3. According to the resultant force F of the fuselage flight load and the initial skin resultant force of each area of ​​the helicopter fuselage, a load distribution result is obtained, and the load distribution result is used for the strength check of the helicopter fuselage frame beam.

2. The helicopter fuselage flight load distribution method according to claim 1, characterized in that: The method further comprises: Step 1: Obtain the values ​​of the angle of attack and sideslip angle in the flight state corresponding to all flight loads of the helicopter fuselage; Step 2: Use computational fluid dynamics (CFD) software to obtain the resultant force Fα of the skin of each area of ​​the helicopter fuselage at different angles of attack when the helicopter flight speed is Vmax and the sideslip angle is 0°; obtain the resultant force Fβ of the skin of each area of ​​the helicopter fuselage at different sideslip angles when the helicopter flight speed is Vmax and the angle of attack is 0°; Step 3: According to the resultant force Fα and resultant force Fβ of the skin in each area of ​​the helicopter fuselage, the initial skin resultant force corresponding to the skin in each area of ​​the helicopter fuselage at different attack angles α and sideslip angles β is obtained to obtain the initial skin resultant force matrix.

3. The helicopter fuselage flight load distribution method according to claim 2, characterized in that: The initial skin force Fαβ=Fα+Fβ-F0, where F0 is the resultant force when the angle of attack and the sideslip angle are both 0°.

4. The helicopter fuselage flight load distribution method according to claim 2, characterized in that: After obtaining the resultant force Fα and the resultant force Fβ of the skin of each area of ​​the helicopter fuselage, the method further includes: According to the results of helicopter fuselage force measurement wind tunnel test, the resultant force Fα and resultant force Fβ of the skin in each area of ​​the helicopter fuselage are corrected.

5. The helicopter fuselage flight load distribution method according to claim 1, characterized in that: The skin of each area of ​​the helicopter fuselage is divided according to the frame beams.

6. A helicopter fuselage flight load distribution device, characterized in that: include: A parameter acquisition module is used to obtain the preset fuselage flight load resultant force F, angle of attack and sideslip angle; An initial reasonable acquisition module is used to determine the initial skin resultant forces corresponding to the skins of various regions of the helicopter fuselage at the preset angle of attack α and sideslip angle β in the initial skin resultant force matrix according to the preset angle of attack and sideslip angle; The distribution module is used to obtain the load distribution result according to the fuselage flight load resultant force F and the initial skin resultant force of each area of ​​the helicopter fuselage. The load distribution result is used for the strength check of the helicopter fuselage frame beam.

7. The helicopter fuselage flight load distribution device according to claim 6, characterized in that: Also includes: Step 1: Obtain the values ​​of the angle of attack and sideslip angle in the flight state corresponding to all flight loads of the helicopter fuselage; Step 2: Use computational fluid dynamics (CFD) software to obtain the resultant force Fα of the skin of each area of ​​the helicopter fuselage at different angles of attack when the helicopter flight speed is Vmax and the sideslip angle is 0°; obtain the resultant force Fβ of the skin of each area of ​​the helicopter fuselage at different sideslip angles when the helicopter flight speed is Vmax and the angle of attack is 0°; Step 3: According to the resultant force Fα and resultant force Fβ of the skin in each area of ​​the helicopter fuselage, the initial skin resultant force corresponding to the skin in each area of ​​the helicopter fuselage at different attack angles α and sideslip angles β is obtained to obtain the initial skin resultant force matrix.

8. The helicopter fuselage flight load distribution device according to claim 7, characterized in that: The initial skin force Fαβ=Fα+Fβ-F0, where F0 is the resultant force when the angle of attack and the sideslip angle are both 0°.

9. The helicopter fuselage flight load distribution device according to claim 7, characterized in that: Also includes: The correction module is used to correct the resultant force Fα and the resultant force Fβ of the skin of each area of ​​the helicopter fuselage according to the result of the helicopter fuselage force measurement wind tunnel test after obtaining the resultant force Fα and the resultant force Fβ of the skin of each area of ​​the helicopter fuselage.

10. The helicopter fuselage flight load distribution device according to claim 6, characterized in that: The skin of each area of ​​the helicopter fuselage is divided according to the frame beams.

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