Method for decomposing and determining noise index parameters of stiffened wall plate of propeller-driven aircraft

Abstract

The invention particularly relates to a method for decomposing and determining noise index parameters of a stiffened wallboard of a propeller-driven aircraft. The method comprises the following steps: step 1, calculating a critical frequency of the stiffened wallboard; step 2, calculating sound transmission loss based on the critical frequency of the stiffened wall plate; 3, calculating noise of a turbulence boundary layer on the surface of the stiffened wall plate; 4, near-field noise of the propeller distributed along the stiffened wall plate is calculated; 5, calculating the noise in the cabin of the propeller aircraft according to the sound transmission loss of the stiffened wall plate, the noise of the turbulent boundary layer on the surface of the stiffened wall plate and the near-field noise of the propeller distributed along the stiffened wall plate; and 6, if the noise in the propeller aircraft cabin cannot meet the noise index requirement in the cabin, adjusting the structure and material parameters of the stiffened wall plate, optimizing the structure and material parameters of the stiffened wall plate, and carrying out the steps 1-5 again until the noise in the propeller aircraft cabin meets the noise index requirement in the cabin. The sound transmission loss and the structure and material parameters of the stiffened wall plate are obtained.

Description

Technical Field

[0001] The present application belongs to the technical field of propeller aircraft reinforced wall panel design, and in particular relates to a method for decomposing and determining noise index parameters of a propeller aircraft reinforced wall panel. Background Art

[0002] During the development of propeller aircraft, it is necessary to control the cabin noise.

[0003] The near-field noise of propeller aircraft mainly comes from the propeller. There are a large number of stiffened panels on propeller aircraft. In order to ensure that the cabin noise meets the index requirements, it is necessary to decompose the cabin noise index into the stiffened panels and determine the structure and material parameters of the stiffened panels. However, at present, there is a lack of efficient and feasible methods for this. In view of this, this application is proposed. Summary of the invention

[0004] The purpose of the present application is to provide a method for decomposing and determining noise index parameters of a propeller aircraft stiffened wall panel, so as to guide the design of the stiffened wall panel during the aircraft development process.

[0005] The technical solution of this application is:

[0006] A method for decomposing and determining noise index parameters of a propeller aircraft reinforced wall panel, comprising:

[0007] Step 1: Calculate the critical frequency of the stiffened wall panel;

[0008] Step 2: Calculate the sound transmission loss based on the critical frequency of the stiffened wall panel;

[0009] Step 3: Calculate the turbulent boundary layer noise on the surface of the stiffened wall panel;

[0010] Step 4: Calculate the near-field noise of the propeller distributed along the stiffened wall panel;

[0011] Step 5: Calculate the cabin noise of the propeller aircraft based on the acoustic transmission loss of the stiffened wall panel, the turbulent boundary layer noise on the surface of the stiffened wall panel, and the near-field noise of the propeller distributed along the stiffened wall panel;

[0012] Step 6: If the cabin noise of the propeller aircraft cannot meet the cabin noise index requirements, adjust the structure and material parameters of the stiffened wall panel, optimize the structure and material parameters of the stiffened wall panel, and repeat steps 1 to 5 until the cabin noise of the propeller aircraft meets the cabin noise index requirements, and obtain the sound transmission loss of the stiffened wall panel and its structure and material parameters.

[0013] According to at least one embodiment of the present application, in the above-mentioned method for determining the noise index parameters of the reinforced wall panel of a propeller aircraft, the structural parameters of the reinforced wall panel include the wall panel section thickness h, the reinforcing rib height h r, reinforcing rib width t, and center distance d between reinforcing ribs.

[0014] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft reinforced wall panel, in step 1, the critical frequency of the reinforced wall panel is calculated, including the critical frequency f in the vertical direction of the wall panel. c1 , critical frequency f in the direction parallel to the wall panel c2 .

[0015] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft stiffened wall panel, step 1 includes:

[0016]

[0017] in,

[0018] c is the speed of sound in air;

[0019] M S is the mass per unit area of ​​the wall panel;

[0020] B1 is the bending stiffness of the wall panel in the vertical direction.

[0021] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft stiffened wall panel, step 1 includes:

[0022] M S =ρ W h[1+(h r / h)(t / d)];

[0023] in,

[0024] ρ W is the density of the siding material.

[0025] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft stiffened wall panel, step 1 includes:

[0026] B1=EI / d;

[0027] in,

[0028] E is the elastic modulus of the siding material;

[0029] I is the moment of inertia of the T-shaped center axis of the wall panel.

[0030] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft stiffened wall panel, step 1 includes:

[0031]

[0032] in,

[0033] B2 is the bending stiffness in the direction parallel to the wall panel.

[0034] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft stiffened wall panel, step 1 includes:

[0035]

[0036] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft stiffened wall panel,

[0037] In step 3, the noise cutoff frequency f is less than the critical frequency f in the vertical direction of the wall panel c1 When , the sound transmission loss TL of the stiffened panel is calculated as:

[0038] TL=TL n -5;

[0039] in,

[0040] TL n is the normal transmission loss of incident sound waves on the stiffened panel;

[0041] TL n =10log 10 (1 / a tn );

[0042] in,

[0043] a tn is the transmission coefficient of sound energy in the stiffened wall panel;

[0044]

[0045] in,

[0046] c1 is the speed of sound propagation in the reinforcing ribs;

[0047] ρ1 is the density of the reinforcing rib material.

[0048] According to at least one embodiment of the present application, in the above-mentioned method for determining the noise index parameter decomposition of the propeller aircraft reinforced wall panel, in step 3, the noise cutoff frequency f is between the critical frequency f in the vertical direction of the wall panel c1 , critical frequency f in the direction parallel to the wall panel c2 When , the sound transmission loss TL of the stiffened panel is calculated as:

[0049] TL=TL n (f c1 )+10log 10 (η)+30log 10 (f / fC1 )-40log 10 [ln(4f / f C1 )]+10log 10 [2π 3 (f C2 / f C1 ) 1 / 2 ];

[0050] in,

[0051] TL n (f c1 ) is the noise cutoff frequency of the reinforced wall panel, f is the critical frequency f in the vertical direction of the wall panel c1 The sound transmission loss at

[0052] η is the damping coefficient of the wall panel material.

[0053] According to at least one embodiment of the present application, in the above-mentioned method for determining the noise index parameter decomposition of the propeller aircraft reinforced wall panel, in step 3, the noise cutoff frequency f is greater than the critical frequency f in the parallel direction of the wall panel c2 When , the sound transmission loss TL of the stiffened panel is calculated as:

[0054] TL=TL n (f c2 )+10log10(η)+30log 10 (f / f C2 )-2;

[0055] in,

[0056] TL n (f c2 ) is the noise cut-off frequency of the stiffened wall panel, f is the critical frequency f in the parallel direction of the wall panel c2 The sound transmission loss at that time.

[0057] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft stiffened wall panel, step three is specifically as follows:

[0058]

[0059] in,

[0060] TBL is the turbulent boundary layer noise on the surface of the stiffened wall panel;

[0061] τ w is the shear stress on the wall of the reinforced wall panel;

[0062] δ * is the displacement thickness of the turbulent boundary layer on the surface of the stiffened panel;

[0063] U0 is the flight speed.

[0064] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft reinforced wall panel, step three includes:

[0065]

[0066]

[0067] in,

[0068] ρ is the air density;

[0069] Re δ Calculate intermediate parameters for shear stress on the wall of the stiffened panel;

[0070] υ is the kinematic viscosity of air.

[0071] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft reinforced wall panel, step three includes:

[0072]

[0073] in,

[0074] x0 is the distance between the reinforced wall panel and the front end of the machine head.

[0075] According to at least one embodiment of the present application, in the above-mentioned method for decomposing and determining noise index parameters of a propeller aircraft stiffened wall panel, step 4 is specifically as follows:

[0076] Based on the flight state of propeller aircraft, a propeller near-field noise source model is constructed. The propeller diameter, power, thrust, number of blades, rotation speed, speed of sound, flight speed, ambient temperature, number of propellers, blade width at 0.8 radius, distance from wingtip to wall panel, and air density are taken as key parameters. The near-field noise ROR of the propeller distributed along the stiffened wall panel within the noise cutoff frequency range is obtained.

[0077] According to at least one embodiment of the present application, in the above-mentioned method for determining noise index parameters of a propeller aircraft reinforced wall panel, step five is specifically as follows:

[0078]

[0079] in,

[0080] SPL is the cabin noise of propeller aircraft.

[0081] This application has at least the following beneficial technical effects:

[0082] A method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels is provided. Based on the open theory analysis of the sound transmission loss of propeller aircraft stiffened wall panels and the cabin noise under the excitation of an external sound source, the cabin noise index is decomposed into the stiffened wall panels. The sound transmission loss of the stiffened wall panels and the structural and material parameters are iteratively calculated to finally obtain the stiffened wall panels that meet the cabin noise index requirements and their structural and material parameters. The method is convenient and efficient and can guide the design of stiffened wall panels during the aircraft development process. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Figure 1 It is a schematic diagram of a method for decomposing and determining noise index parameters of a propeller aircraft reinforced wall panel provided in an embodiment of the present application;

[0084] Figure 2 It is a schematic diagram of the reinforced wall panel structure model provided in an embodiment of the present application.

[0085] In order to better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product. In addition, the drawings are only used for illustrative purposes and should not be construed as limitations on the present application. DETAILED DESCRIPTION

[0086] In order to make the technical solution and advantages of the present application clearer, the technical solution of the present application will be described in further detail in detail and in detail with reference to the accompanying drawings. It can be understood that the specific embodiments described here are only partial embodiments of the present application, which are only used to explain the present application, not to limit the present application. It should be noted that, for the convenience of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design.

[0087] In addition, unless otherwise defined, the technical terms or scientific terms used in the description of this application shall have the usual meanings understood by those of ordinary skill in the art to which this application belongs. The words used in the description of this application to indicate orientation are only used to indicate relative directions or positional relationships. When the absolute position of the described object changes, its relative positional relationship may also change accordingly. The word "include" used in the description of this application indicates that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, but does not exclude other elements or objects.

[0088] In addition, it should be noted that, unless otherwise clearly specified and limited, the words "installation", "connection" and similar terms used in the description of this application should be understood in a broad sense. For example, the connection can be a fixed connection or a detachable 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. Technical personnel in the field can understand its specific meaning in this application according to the specific circumstances.

[0089] The embodiment of the present application provides a method for decomposing and determining noise index parameters of a propeller aircraft stiffened panel based on the theoretical analysis of the acoustic transmission loss of the propeller aircraft stiffened panel and the cabin noise under the excitation of an external sound source. Figure 1 shown.

[0090] Step 1: Calculate the critical frequency of the stiffened wall panel.

[0091] The structural parameters of the reinforced wall panel mainly include the wall panel section thickness h, the reinforcing rib height h r , rib width t, and center distance d between ribs, the structural model of the stiffened wall panel is constructed as follows: Figure 2 shown.

[0092] The stiffness of the stiffened panel in the direction perpendicular to and parallel to the ribs is different, so there are critical frequencies in two directions, including the critical frequency f in the perpendicular direction of the panel. c1 , critical frequency f in the direction parallel to the wall panel c2 .

[0093]

[0094] in,

[0095] c is the speed of sound in air;

[0096] M S is the mass per unit area of ​​the wall panel;

[0097] B1 is the bending stiffness of the wall panel in the vertical direction.

[0098] M S =ρ W h[1+(h r / h)(t / d)];

[0099] in,

[0100] ρ W is the density of the siding material.

[0101] B1=EI / d;

[0102] in,

[0103] E is the elastic modulus of the siding material;

[0104] I is the moment of inertia of the T-shaped center axis of the wall panel.

[0105]

[0106] in,

[0107] B2 is the bending stiffness in the direction parallel to the wall panel.

[0108]

[0109] Step 2: Calculate the sound transmission loss based on the critical frequency of the stiffened wall panel.

[0110] The noise cut-off frequency f is less than the critical frequency f in the vertical direction of the wall panel c1 When , the sound transmission loss TL of the stiffened panel is calculated as follows:

[0111] TL=TL n -5;

[0112] in,

[0113] TL n is the normal transmission loss of incident sound waves in the reinforced panel.

[0114] TL n =10log 10 (1 / a tn );

[0115] in,

[0116] a tn is the transmission coefficient of sound energy in the stiffened wall panel.

[0117]

[0118]

[0119] in,

[0120] c1 is the speed of sound propagation in the reinforcing ribs;

[0121] ρ1 is the density of the reinforcing rib material.

[0122] The noise cut-off frequency f is between the critical frequency f in the vertical direction of the wall panel c1 , critical frequency f in the direction parallel to the wall panel c2 When , the sound transmission loss TL of the stiffened panel is calculated as follows:

[0123] TL=TL n (f c1 )+10log 10 (η)+30log 10 (f / f C1 )-40log 10 [ln(4f / f C1 )]+10log 10 [2π 3 (f C2 / f C1 ) 1 / 2 ];

[0124] in,

[0125] TL n (f c1 ) is the noise cutoff frequency of the reinforced wall panel, f is the critical frequency f in the vertical direction of the wall panel c1 The sound transmission loss at

[0126] η is the damping coefficient of the wall panel material.

[0127] The noise cut-off frequency f is greater than the critical frequency f in the direction parallel to the wall c2 When , the sound transmission loss TL of the stiffened panel is calculated as follows:

[0128] TL=TL n (f c2 )+10log10(η)+30log 10 (f / f C2 )-2;

[0129] in,

[0130] TL n (f c2 ) is the noise cut-off frequency of the stiffened wall panel, f is the critical frequency f in the parallel direction of the wall panel c2 The sound transmission loss at that time.

[0131] Step 3: Calculate the turbulent boundary layer noise on the surface of the stiffened wall panel.

[0132]

[0133] in,

[0134] TBL is the turbulent boundary layer noise on the surface of the stiffened wall panel;

[0135] τ w is the shear stress on the wall of the reinforced wall panel;

[0136] δ * is the displacement thickness of the turbulent boundary layer on the surface of the stiffened panel;

[0137] U0 is the flight speed.

[0138]

[0139]

[0140] in,

[0141] ρ is the air density;

[0142] Re δ Calculate intermediate parameters for shear stress on the wall of the stiffened panel;

[0143] υ is the kinematic viscosity of air.

[0144]

[0145] in,

[0146] x0 is the distance between the reinforced wall panel and the front end of the machine head.

[0147] Step 4: Calculate the near-field noise of the propeller distributed along the stiffened wall panel.

[0148] Based on the flight state of propeller aircraft, a propeller near-field noise source model is constructed. The propeller diameter, power, thrust, number of blades, rotation speed, speed of sound, flight speed, ambient temperature, number of propellers, blade width at 0.8 radius, distance from wingtip to wall panel, and air density are taken as key parameters. The near-field noise ROR of the propeller distributed along the stiffened wall panel within the noise cutoff frequency range is obtained.

[0149] Step 5: Calculate the cabin noise of the propeller aircraft based on the sound transmission loss of the stiffened wall panel, the turbulent boundary layer noise on the surface of the stiffened wall panel, and the near-field noise of the propeller distributed along the stiffened wall panel.

[0150]

[0151]

[0152] in,

[0153] SPL is the cabin noise of propeller aircraft.

[0154] Step 6. If the cabin noise of the propeller aircraft cannot meet the cabin noise index requirements, adjust the structure and material parameters of the stiffened wall panel, optimize the structure and material parameters of the stiffened wall panel, and repeat steps 1 to 5 until the cabin noise of the propeller aircraft meets the cabin noise index requirements. The sound transmission loss of the stiffened wall panel and its structure and material parameters are obtained as the design indicators of the stiffened wall panel.

[0155] In a specific example, the wall panel section thickness h = 3 mm, the reinforcing rib height h r =3mm, rib width t = 2mm, rib center distance d = 10mm, the wall panel unit area mass M is calculated S , the moment of inertia I of the T-shaped center axis of the wall panel.

[0156] The wall panels and reinforcing ribs are made of aluminum alloy, with a material density of W=ρ1=2700kg / m3, material elastic modulus E=70000MPa, material damping coefficient η=0.3, speed of sound propagation in the reinforcement rib c1=5000m / s, propeller aircraft cruising altitude 5km, speed of sound in the air on both sides of the wall panel c=320m / s, the bending stiffness B1 in the vertical direction of the wall panel, the bending stiffness B2 in the parallel direction of the wall panel, and the transmission coefficient a of sound energy in the reinforced wall panel are calculated. tn , sound wave incident normal transmission loss TL of reinforced wall panel n , and then the sound transmission loss TL of the stiffened wall panel is obtained.

[0157] Select the propeller aircraft flight speed U0 = 0.7Ma, the distance between the stiffened wall panel and the front end of the nose x0 = 5m, the air motion viscosity υ = 2.8×10-5, and calculate the turbulent boundary layer noise TBL on the stiffened wall panel surface.

[0158] With propeller diameter, power, thrust, number of blades, rotation speed, speed of sound, flight speed, ambient temperature, number of propellers, blade width at 0.8 radius, distance from wingtip to wall panel and air density as key parameters, a propeller near-field noise source model is constructed, and the near-field noise ROR of the propeller distributed along the stiffened wall panel is obtained.

[0159] The propeller aircraft cabin noise SPL is calculated based on the sound transmission loss of the stiffened wall panel, the turbulent boundary layer noise on the surface of the stiffened wall panel, and the near-field noise of the propeller distributed along the stiffened wall panel. If the cabin noise index is not met, the stiffened wall panel structure and material parameters are adjusted, and the stiffened wall panel structure and material parameters are optimized. The above process is repeated until the propeller aircraft cabin noise SPL meets the cabin noise index requirements, and the sound transmission loss TL of the stiffened wall panel and its structure and material parameters are obtained. Among them, the structural material of the stiffened wall panel can specifically include the wall panel section thickness h, the reinforcing rib height h r , reinforcing rib width t, center distance d between reinforcing ribs, etc. The material parameters of the reinforced wall panel specifically include the density, elastic modulus, moment of inertia and other aspects of the structure.

[0160] The above-mentioned disclosed method for decomposing and determining the noise index parameters of the propeller aircraft reinforced wall panel is based on the theoretical analysis of the sound transmission loss of the propeller aircraft reinforced wall panel and the cabin noise under the excitation of the external sound source, and the cabin noise index is decomposed into the reinforced wall panel. The sound transmission loss and structure and material parameters of the reinforced wall panel are iteratively calculated to finally obtain the sound transmission loss of the reinforced wall panel and its structure and material parameters that meet the cabin noise index requirements. The method is convenient and efficient, and can guide the design of the reinforced wall panel during the aircraft development process.

[0161] So far, the technical solution of the present application has been described in conjunction with the preferred embodiments shown in the accompanying drawings. Those skilled in the art should understand that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A method for determining noise index parameters of a propeller aircraft reinforced wall panel, characterized in that: include: Step 1: Calculate the critical frequency of the stiffened wall panel; Step 2: Calculate the sound transmission loss based on the critical frequency of the stiffened wall panel; Step 3: Calculate the turbulent boundary layer noise on the surface of the stiffened wall panel; Step 4: Calculate the near-field noise of the propeller distributed along the stiffened wall panel; Step 5: Calculate the cabin noise of the propeller aircraft based on the acoustic transmission loss of the stiffened wall panel, the turbulent boundary layer noise on the surface of the stiffened wall panel, and the near-field noise of the propeller distributed along the stiffened wall panel; Step 6: If the cabin noise of the propeller aircraft cannot meet the cabin noise index requirements, adjust the structure and material parameters of the stiffened wall panel, optimize the structure and material parameters of the stiffened wall panel, and repeat steps 1 to 5 until the cabin noise of the propeller aircraft meets the cabin noise index requirements, and obtain the sound transmission loss of the stiffened wall panel and its structure and material parameters.

2. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 1, characterized in that: The structural parameters of the reinforced wall panel include the wall panel section thickness h, the reinforcing rib height h r , reinforcing rib width t, and center distance d between reinforcing ribs.

3. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 2, characterized in that: In step 1, the critical frequencies of the stiffened panels are calculated, including the critical frequencies f in the vertical direction of the panels. c1 , critical frequency f in the direction parallel to the wall panel c2 .

4. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 3, characterized in that: In step one, there are: in, c is the speed of sound in air; M S is the mass per unit area of ​​the wall panel; B1 is the bending stiffness of the wall panel in the vertical direction.

5. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 4, characterized in that: In step one, there are: M S =ρ W h[1+(h r / h)(t / d)]; in, ρ W is the density of the siding material.

6. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 5, characterized in that: In step one, there are: B1=EI / d; in, E is the elastic modulus of the siding material; I is the moment of inertia of the T-shaped center axis of the wall panel.

7. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 6, characterized in that: In step one, there are: in, B2 is the bending stiffness in the direction parallel to the wall panel.

8. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 7, characterized in that: In step one, there are:

9. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 8, characterized in that: In step 3, the noise cutoff frequency f is less than the critical frequency f in the vertical direction of the wall panel c1 When , the sound transmission loss TL of the stiffened panel is calculated as: <h2 style=";text-align:left;direction:ltr">TL=TL<h2 style=";text-align:left;direction:ltr"> n <h2 style=";text-align:left;direction:ltr"> -5; in, TL n is the normal transmission loss of incident sound waves in the stiffened wall panel; TL n D10log 10 (1 / a tn )4 in, a tn is the transmission coefficient of sound energy in the stiffened wall panel; in, c1 is the speed of sound propagation in the reinforcing ribs; ρ1 is the density of the reinforcing rib material.

10. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 9, characterized in that: In step 3, the noise cutoff frequency f is between the critical frequency f in the vertical direction of the wall panel c1 , critical frequency f in the direction parallel to the wall panel c2 When , the sound transmission loss TL of the stiffened panel is calculated as: TL=TL n (f c1 )+10log 10 (n)+30log 10 (f / f C1 )-40log 10 [ln(4f / f C1 )]+10log 10 [2π 3 (f C2 / f C1 ) 1 / 2 ]; in, TL n (f c1 ) is the noise cutoff frequency of the reinforced wall panel, f is the critical frequency f in the vertical direction of the wall panel c1 The sound transmission loss at η is the damping coefficient of the wall panel material.

11. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 10, characterized in that: In step 3, the noise cutoff frequency f is greater than the critical frequency f in the direction parallel to the wall panel c2 When , the sound transmission loss TL of the stiffened panel is calculated as: TL=TL n (f c2 )+10log10(η)+30log 10 (f / f C2 )-2; in, TL n (f c2 ) is the noise cut-off frequency of the stiffened wall panel, f is the critical frequency f in the parallel direction of the wall panel c2 The sound transmission loss at that time.

12. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 11, characterized in that: Step three is as follows: in, TBL is the turbulent boundary layer noise on the surface of the stiffened wall panel; τ w is the shear stress on the wall of the reinforced wall panel; δ * is the displacement thickness of the turbulent boundary layer on the surface of the stiffened panel; U0 is the flight speed.

13. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 12, characterized in that: In step three, there are: in, ρ is the air density; Re δ Calculate intermediate parameters for shear stress on the wall of the stiffened panel; υ is the kinematic viscosity of air.

14. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 13, characterized in that: In step three, there are: in, x0 is the distance between the reinforced wall panel and the front end of the machine head.

15. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 14, characterized in that: Step 4 is as follows: Based on the flight state of propeller aircraft, a propeller near-field noise source model is constructed. The propeller diameter, power, thrust, number of blades, rotation speed, speed of sound, flight speed, ambient temperature, number of propellers, blade width at 0.8 radius, distance from wingtip to wall panel, and air density are taken as key parameters. The near-field noise ROR of the propeller distributed along the stiffened wall panel within the noise cutoff frequency range is obtained.

16. The method for decomposing and determining noise index parameters of propeller aircraft stiffened wall panels according to claim 15, characterized in that: Step 5 is as follows: in, SPL is the cabin noise of propeller aircraft.

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