Aircraft repeated pressurizing test load spectrum simplification method

Abstract

The invention belongs to the technical field of airplane repeated pressurizing tests, and particularly relates to an airplane repeated pressurizing test load spectrum simplification method, which comprises the following steps of: 1, determining a repeated pressurizing load spectrum and a maximum pressurizing load; step 2, rain flow counting is carried out on charging load spectrums of different mission profiles in the repeated charging load spectrums, and a load level is determined according to a rain flow result; 3, calculating the relative damage of each mission profile based on the load level; 4, calculating the relative damage of all mission profiles; 5, simplifying the load series of the repeated pressurizing load spectrum to obtain the load series of a simplified load spectrum; and step 6, according to a relative damage equality principle, determining load values of different load levels of the simplified load spectrum and proportions of the load values.

Description

Technical Field

[0006] The present application belongs to the technical field of aircraft repeated pressurization tests, and in particular relates to a method for simplifying a load spectrum of an aircraft repeated pressurization test. Background Art

[0007] Fuselage pressurization is one of the important load sources, especially for civil aircraft and transport aircraft, the pressurization load is the main load on the fuselage.

[0008] The aircraft repeated pressurization test is a test to verify the aircraft's ability to withstand pressurization loads. The fuselage pressurization load is related to the type of aircraft design mission profile, flight altitude, mission segment, etc. The complete aircraft repeated pressurization test load spectrum is very complex, which is not conducive to the test. Therefore, it is of great significance to simplify the aircraft repeated pressurization test load spectrum. In view of this, this application is proposed. Summary of the invention

[0009] The purpose of the present application is to provide a method for simplifying the load spectrum of an aircraft repeated pressurization test to overcome or alleviate at least one of the known technical deficiencies.

[0010] The technical solution of this application is:

[0011] A method for simplifying a load spectrum of an aircraft repeated pressurization test, comprising:

[0012] Step 1, determining the repeated pressurization load spectrum and the maximum pressurization load;

[0013] Step 2: count the rain flow of the pressurization load spectrum of different mission profiles in the repeated pressurization load spectrum, and determine the load level according to the rain flow result;

[0014] Step 3: Based on the load level, calculate the relative damage of each mission profile;

[0015] Step 4: Calculate the relative damage of all mission profiles;

[0016] Step 5, simplifying the load series of the repeated pressurization load spectrum to obtain the load series of the simplified load spectrum;

[0017] Step 6: According to the principle of equal relative damage, determine the load values ​​and their proportions of different load levels in the simplified load spectrum.

[0018] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the aircraft re-pressurization test load spectrum, in step one, it is determined that the re-pressurization load spectrum is composed of pressurization load spectra under different mission profiles.

[0019] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the load spectrum of the aircraft repeated pressurization test, in step one, the maximum pressurization load is the maximum pressurization load under all mission profiles.

[0020] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the aircraft repeated pressurization test load spectrum, in step two, rainflow counting is performed on the pressurization load spectrum of different mission profiles in the repeated pressurization load spectrum, and the pressurization load spectrum is compiled to include different numbers of load levels.

[0021] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the load spectrum of the aircraft repeated pressurization test, in step 2, the load level determined according to the rain flow result can be expressed as (P i,j , ρ i,j ),in,

[0022] P i,j is the peak load of the jth load pair under the i-th mission profile;

[0023] ρ i,j is the valley load of the jth load pair under the i-th mission profile.

[0024] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the load spectrum of the aircraft repeated pressurization test, step three is specifically as follows:

[0025]

[0026] in,

[0027] ζ i is the relative damage of the i-th mission profile;

[0028] n is the total number of loads in the mission profile;

[0029] Q i,j is the relative damage of the jth load in the i-th mission profile, and is the load level (P i,j , ρ i,j ) function;

[0030] α is the characteristic parameter for relative damage calculation.

[0031] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the load spectrum of the aircraft repeated pressurization test, in step three, the relative damage calculation characteristic parameter α is selected as 4.

[0032] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the load spectrum of the aircraft repeated pressurization test, in step 3, Q i,j =[P i,j ×(P i,j -ρ i,j )] 1 / 2 .

[0033] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the load spectrum of the aircraft repeated pressurization test, step 4 is specifically as follows:

[0034]

[0035] in,

[0036] ζ is the relative damage of all mission profiles;

[0037] N is the total number of mission profiles;

[0038] ψ i is the profile ratio of the i-th mission profile.

[0039] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the aircraft repeated pressurization test load spectrum, in step five, the load level of the repeated pressurization load spectrum is simplified, and the load level of the simplified load spectrum is obtained to be 1-3.

[0040] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the load spectrum of the aircraft repeated pressurization test, in step six, it is determined that the simplified load spectrum includes the maximum pressurization load.

[0041] According to at least one embodiment of the present application, in the above-mentioned method for simplifying the load spectrum of the aircraft repeated pressurization test, in step six, the minimum load in the simplified load spectrum is determined to be 5-10 KPa.

[0042] This application has at least the following beneficial technical effects:

[0043] A method for simplifying a load spectrum for a repeated pressurization test of an aircraft is provided. The load levels of the repeated pressurization load spectrum are simplified to obtain the load levels of the simplified load spectrum. Then, according to the principle of relative damage equality, the load values ​​and their proportions of different load levels of the simplified load spectrum are determined, thereby simplifying the repeated pressurization load spectrum and facilitating the repeated pressurization test. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a schematic diagram of a method for simplifying a load spectrum of an aircraft repeated pressurization test provided in an embodiment of the present application;

[0045] Figure 2 It is a schematic diagram of the pressurization load spectrum of typical tasks 1 and 2 sections of the repeated pressurization load spectrum provided in the embodiment of the present application;

[0046] Figure 3 It is a schematic diagram of the pressurization load spectrum of the repeated pressurization load spectrum training task 2 section provided in an embodiment of the present application.

[0047] 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

[0048] 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.

[0049] 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.

[0050] A simplified method for aircraft repeated pressurization test load spectrum, such as Figure 1 shown.

[0051] Step 1: Determine the repeated pressurization load spectrum and the maximum pressurization load.

[0052] The repeated pressurization load spectrum is a description of the pressurization loads in different mission profiles during the design and use of the aircraft, and is composed of pressurization load spectra under different mission profiles.

[0053] The maximum pressure load of the repeated pressure load spectrum is the maximum pressure load under all mission profiles, denoted by P max express.

[0054] Step 2: Count the rainflow of the pressurization load spectrum of different mission profiles in the repeated pressurization load spectrum, and determine the load level according to the rainflow results.

[0055] Rainflow counting is a load spectrum processing method that can remove load levels that do not cause damage in the load spectrum. Rainflow counting is performed on the pressurization load spectra of different mission profiles in the repeated pressurization load spectrum, and the pressurization load spectrum can be compiled into a system containing different numbers of load levels.

[0056] The load level determined based on the rain flow results can be expressed as (P i,j , ρ i,j ),in,

[0057] P i,j is the peak load of the jth load pair under the i-th mission profile;

[0058] ρ i,jis the valley load of the jth load pair under the i-th mission profile.

[0059] Step 3: Based on the load level, calculate the relative damage of each mission profile.

[0060]

[0061] in,

[0062] ζ i is the relative damage of the i-th mission profile;

[0063] n is the total number of loads in the mission profile;

[0064] Q i,j is the relative damage of the jth load in the i-th mission profile, and is the load level (P i,j , ρ i,j ) function;

[0065] α is the characteristic parameter for relative damage calculation, which is related to the SN curve. For aircraft fuselage structures, 4 can generally be selected.

[0066] Q i,j =[P i,j ×(P i,j -ρ i,j )] 1 / 2 .

[0067] Step 4: Calculate the relative damage of all mission profiles.

[0068]

[0069] in,

[0070] ζ is the relative damage of all mission profiles;

[0071] N is the total number of mission profiles;

[0072] ψ i is the profile ratio of the i-th mission profile.

[0073] Step 5: Simplify the load series of the repeated pressurization load spectrum to obtain the load series of the simplified load spectrum.

[0074] The load levels of the simplified load spectrum can generally be selected from 1 to 3, which is determined based on the repeated pressurization test results.

[0075] Step 6: According to the principle of equal relative damage, determine the load values ​​and their proportions of different load levels in the simplified load spectrum.

[0076] The relative damage calculation of the simplified load spectrum can be specifically performed based on the relative damage of each mission profile and the relative damage of all mission profiles mentioned above, which will not be elaborated here.

[0077] The simplified load spectrum generally needs to include the maximum pressure load P max , the minimum load is generally selected as 5-10KPa.

[0078] In a specific implementation, it is proposed to simplify the load spectrum of the aircraft repeated pressurization test. The simplified load spectrum includes two levels, each accounting for 50%. The method for simplifying the load spectrum of the aircraft repeated pressurization test disclosed in the above embodiment is implemented as follows:

[0079] S1. Obtain the repeated charging load spectrum and the maximum charging load.

[0080] The aircraft mission profile and its maximum pressurization load are as follows: Serial number Mission Profile Maximum pressure load / KPa Section Scale 1 Typical Task 1 50 25％ 2 Typical Task 2 55 10％ 3 Typical Task 3 30 25％ 4 Training Mission 1 0 20％ 5 Training Mission 2 50 20％

[0081] Maximum pressure load P max =55KPa.

[0082] Among them, the pressure load spectrum of typical mission 1 and 2 profiles is as follows: Figure 2 As shown in Figure 2, the pressure load spectrum of the training task 2 section is as follows: Figure 3 shown.

[0083] S2. Count the rain flow of the pressurization load spectrum of different mission profiles in the repeated pressurization load spectrum, and determine the load level according to the rain flow results, as shown in the following table:

[0084] S3. Based on the load level, calculate the relative damage of each mission profile, as shown in the following table: Mission Profile Typical Task 1 Typical Task 2 Typical Task 3 Training Mission 1 Training Mission 2 Relative damage 6250000 12213125 810000 1 6250000

[0085] S4. Calculate the relative damage of all mission profiles ζ = 4236312.5.

[0086] S5. Simplify the load order of the repeated pressurization load spectrum, and obtain a simplified load order of 2.

[0087] S6. According to the principle of equal relative damage, determine the load values ​​and their proportions of different load levels of the simplified load spectrum, as shown in the following table: Load level Maximum load / KPa Minimum load / KPa Proportion 1 55 5 50％ 2 38.7 5 50％

[0088] The method for simplifying the aircraft repeated pressurization test load spectrum disclosed in the above-mentioned embodiment obtains the load level of the simplified load spectrum by simplifying the load level of the repeated pressurization load spectrum, and then determines the load values ​​and their proportions of different load levels of the simplified load spectrum according to the principle of relative damage equality, thereby achieving the simplification of the repeated pressurization load spectrum and facilitating the repeated pressurization test.

[0089] 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 simplifying load spectrum of aircraft repeated pressurization test, characterized in that: include: Step 1, determining the repeated pressurization load spectrum and the maximum pressurization load; Step 2: count the rain flow of the pressurization load spectrum of different mission profiles in the repeated pressurization load spectrum, and determine the load level according to the rain flow result; Step 3: Based on the load level, calculate the relative damage of each mission profile; Step 4: Calculate the relative damage of all mission profiles; Step 5, simplifying the load series of the repeated pressurization load spectrum to obtain the load series of the simplified load spectrum; Step 6: According to the principle of equal relative damage, determine the load values ​​and their proportions of different load levels in the simplified load spectrum.

2. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 1, characterized in that: In step 1, it is determined that the repeated pressurization load spectrum is composed of pressurization load spectra under different mission profiles.

3. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 2, characterized in that: In step 1, the maximum pressure load is the maximum pressure load under all mission profiles.

4. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 3, characterized in that: In step 2, rain flow counting is performed on the pressurization load spectra of different mission profiles in the repeated pressurization load spectrum, and the pressurization load spectrum is compiled into load levels containing different numbers.

5. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 4, characterized in that: In step 2, the load level determined based on the rain flow results can be expressed as (P i,j , ρ i,j ),in, P i,j is the peak load of the jth load pair under the i-th mission profile; ρ i,j is the valley load of the jth load pair under the i-th mission profile.

6. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 5, characterized in that: Step three is as follows: in, ζ i is the relative damage of the i-th mission profile; n is the total number of loads in the mission profile; Q i,j is the relative damage of the jth load in the i-th mission profile, and is the load level (P i,j , ρ i,j ) function; α is the characteristic parameter for relative damage calculation.

7. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 6, characterized in that: In step three, the relative damage calculation characteristic parameter α is selected as 4.

8. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 7, characterized in that: In step 3, Q i,j =[P i,j ×(P i,j -ρ i,j )] 1 / 2 .

9. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 8, characterized in that: Step 4 is as follows: [0001] [0002] Wherein, [0003]ζ is the relative damage of all mission profiles; [0004] N is the total number of mission profiles; [0005] i is the profile ratio of the i-th mission profile.

10. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 9, characterized in that: In step 5, the load levels of the repeated pressurization load spectrum are simplified, and the load levels of the simplified load spectrum are obtained to be 1-3.

11. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 10, characterized in that: In step six, it is determined that the simplified load spectrum includes the maximum charging load.

12. The method for simplifying the load spectrum of an aircraft repeated pressurization test according to claim 11, characterized in that: In step six, determine the minimum load in the simplified load spectrum and select 5-10KPa.

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