Stress Calculation Method Based on Aircraft Borne Life Management System

Abstract

The present invention relates to a stress calculation method based on an airborne life management system, which is characterized by including the following steps: Step S1: Select the point with the maximum stress or the minimum safety factor in the components of the engine as the assessment point; wherein, the components of the engine include multiple parts, and the multiple parts are multi-stage turbine blades, multi-stage turbine disks, multi-stage compressor blades, and multi-stage compressor disks; Step S2: Run the engine, and record multiple sets of data as time increases, wherein each set of data includes the rotational speed and temperature of each part in the components of the engine; Step S3: Process the multiple sets of data differently according to different application environments of the engine, and calculate the equivalent stress of the preset assessment point of each part at any moment. The present invention can calculate the stress of aircraft engine parts at each moment during flight in a very short time, so that the calculation of part life damage can meet the requirements of the airborne calculation and ground calculation of the aircraft engine life management system in terms of time.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine life management systems, and in particular to a stress calculation method based on an airborne life management system. Background Art

[0002] An aero-engine life management system can enable relevant personnel to timely know the life damage status of key and important parts of the engine, thereby improving the safety and reliability of the engine and the aircraft. It can enable decision-making departments to reasonably arrange aircraft departures according to the life status of engine parts, improve the departure rate and the combat readiness rate of the aircraft, and reasonably arrange engine maintenance and repair, improving the maintainability and economy of the engine.

[0003] Combined with Figure 1 and Figure 2 , an aero-engine life management system includes an airborne part and a ground part.

[0004] Life damage needs to be calculated according to the stress magnitude and temperature of parts. The stress calculation takes more than 90% of the total time in the whole process. Under flight conditions, it is necessary to obtain the stress value of each key part of the part at each moment in real time according to a large number of flight parameters collected by the acquisition system. Since the computing power of the computer equipped on the aircraft is very limited, a fast stress calculation method is required.

[0005] The currently widely used finite element stress calculation method cannot meet this requirement. Even when processing with a ground system, due to the large amount of flight parameter data, a fast stress calculation method is also required. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the present invention discloses a stress calculation method based on an airborne life management system.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A stress calculation method based on an airborne life management system includes the following steps:

[0009] Step S1: Select the point with the maximum stress or the minimum safety factor in the components of the engine as the assessment point; among them, the components of the engine include multiple parts, and the multiple parts are multi-stage turbine blades, multi-stage turbine disks, multi-stage compressor blades, and multi-stage compressor disks;

[0010] Step S2: Run the engine. As time increases, record multiple groups of data. Among them, each group of data includes the rotational speed and temperature of each part in the components of the engine;

[0011] Step S3: Process the multiple groups of data differently according to different application environments of the engine, and calculate the equivalent stress of the preset assessment point of each part at any moment;

[0012] Among them, when the engine is in the first application environment, the first equivalent stress corresponding to the designed value of the initial speed of the gas turbine rotor or the designed value of the initial speed of the power turbine is obtained, and the equivalent stress of the preset assessment points of each part in each group of data is calculated according to the first equivalent stress;

[0013] When the engine is in the second application environment, multiple working conditions are set, and each working condition considers any one of the centrifugal load, temperature load, and aerodynamic load. For different working conditions, stress calculations are performed on the preset assessment points, and the stress components of the preset assessment points are respectively obtained, and the equivalent stress of the preset assessment points of each part in each group of data is calculated according to the stress components.

[0014] Its further technical feature is that: for different working conditions, the method for performing stress calculation on the preset assessment points is as follows: if the working condition is that the designed speed of the gas turbine rotor speed or the power turbine speed is set to the rated speed, the centrifugal load is calculated by finite element; if the working condition is that the temperature before the power turbine speed takes the rated temperature, the temperature load is calculated by using the aerodynamic design method; if the working condition is that the temperature before the power turbine speed takes 80% of the rated temperature, the temperature load is calculated by using the aerodynamic design method; if the working condition is that the designed speed of the gas turbine rotor speed or the power turbine speed is 80% of the rated speed, the aerodynamic load is calculated by using the aerodynamic design method; if the working condition is that the designed speed of the gas turbine rotor speed or the power turbine speed is 80% of the rated speed, the aerodynamic load is calculated by using the aerodynamic design method.

[0015] Its further technical feature is that: in the second working condition, the method for calculating the temperature load is as follows: obtain the rated value of the temperature before the power turbine speed, and calculate the first actual temperature value corresponding to the rated value and the second actual temperature value corresponding to the reduction value respectively according to the rated value of the temperature before the power turbine speed and the reduction value of the flight parameters of the temperature before the power turbine speed; calculate the actual temperature value of the assessment points of each part in each group of data according to the first actual temperature value and the second actual temperature value.

[0016] Its further technical feature is that: the reduction coefficient of the reduction value is 0.8 or 0.88 or 0.76.

[0017] Its further technical feature is that: when the engine is in the first application environment, the formula for obtaining the equivalent stress corresponding to the designed value of the gas turbine rotor speed or the designed value of the power turbine speed and calculating the equivalent stress of the assessment points of each part in each group of data according to the equivalent stress is as follows:

[0018]

[0019] Where: S is the equivalent stress at the assessment point, Sk is the first equivalent stress corresponding to the design value of the gas turbine rotor speed or the design value of the power turbine speed, N is the actual value of the gas turbine rotor speed or the actual value of the power turbine speed corresponding to each group of data, and N100 is the design value of the gas turbine rotor speed or the design value of the power turbine speed.

[0020] Its further technical feature is that when the engine is in the second working state, multiple working conditions are set, and each working condition considers one of the centrifugal load, temperature load, and aerodynamic load. For different working conditions, the finite element method is used to calculate the stress of the parts to be assessed, and the stress components at the assessment points are obtained respectively. The formula for calculating the equivalent stress at the assessment points of each part in each group of data is as follows:

[0021]

[0022] Where: S n is the stress component, S1 n is the nth stress component in the first working condition, N is the actual value of the gas turbine rotor speed or the actual value of the power turbine speed corresponding to each group of data, N100 is the design value of the gas turbine rotor speed or the design value of the power turbine speed, B n0 is the first correction coefficient of the nth stress component, B n1 is the second correction coefficient of the nth stress component, T is the T45 temperature value of each group of data, B n2 is the third correction coefficient of the nth stress component, B n3 is the fourth correction coefficient of the nth stress component, S 2n is the nth stress component in the second working condition, S 3n is the nth stress component in the third working condition, T100 is the rated value of the T45 speed, T80 is the first reduction value of the T45 speed, B m1 is the second correction coefficient of the nth stress component, B n2 is the third correction coefficient of the nth stress component, B n3 is the fourth correction coefficient of the nth stress component, S n4 is the nth stress component in the fourth working condition, S 5n is the nth stress component in the fifth working condition, S e is the equivalent stress at the assessment point.

[0023] Its further technical feature is that in step S3, there are six stress components, and the six stress components are the normal stress in the x direction, the normal stress in the y direction, the normal stress in the z direction, the shear stress in the xy direction, the shear stress in the yz direction, and the shear stress in the zx direction.

[0024] A life prediction method based on an airborne life management system, including the stress calculation method based on the airborne life management system described above, further includes step S4: processing each group of data differently according to different application environments of the engine, and calculating the actual temperature value of a preset assessment point.

[0025] Its further technical feature is that: processing each group of data differently according to the first application environment of the engine, the formula for calculating the actual temperature value of the preset assessment point is as follows:

[0026] Tr = A0 + A1×T

[0027]

[0028] In the formula: Tr is the actual temperature value of the assessment point, A0 is the first correction temperature, A1 is the second correction temperature, T is the T45 temperature value of each group of data, T1 is the first actual temperature value corresponding to the rated value of the T45 speed, T2 is the second actual temperature value corresponding to the first reduction value of the T45 speed, T100 is the rated value of the T45 temperature, and T80 is the first reduction value of the T45 temperature.

[0029] Its further technical feature is that: processing each group of data differently according to the second application environment of the engine, the formula for calculating the actual temperature value of the preset assessment point is as follows:

[0030] Tr = A0 + A1×T + A2×T 2

[0031]

[0032] C1 = (T1×T76 - T3×T100)×(T88 - T76)×T88

[0033] C2 = (T2×T76 - T3×T88)×(T100 - T76)×T100

[0034] CC = (T100 - T88)×(T88 - T76)×(T100 - T76)

[0035] C3 = (T1 - T3)×(T86 2 -T76 2 )

[0036] C4 = (T2 - T3)×(T100 2 -T76 2 )

[0037] C5 = (T1 - T3)×(T86 - T76)

[0038] C6 = (T2 - T3)×(T100 - T76)

[0039] Where: Tr is the actual temperature value of the assessment point, A0 is the first correction temperature, A1 is the second correction temperature, A2 is the third correction temperature, T is the T45 temperature value of each group of data, C1 is the first conversion temperature, C2 is the second conversion temperature, CC is the reference conversion temperature, C3 is the third conversion temperature, C4 is the fourth conversion temperature, C5 is the fifth conversion temperature, C6 is the sixth conversion temperature, T1 is the first actual temperature value corresponding to the rated value of the T45 rotation speed, T2 is the second actual temperature value corresponding to the second reduction value of the T45 rotation speed, T3 is the third actual temperature value corresponding to the third reduction value of the T45 rotation speed, T100 is the rated value of the T45 temperature, T88 is the first reduction value of the T45 temperature, T86 is the second reduction value of the T45 temperature, and T76 is the third reduction value of the T45 temperature.

[0040] The above technical solution of the present invention has the following advantages compared with the prior art:

[0041] The present invention provides a fast part stress calculation method for the airborne and ground systems of an aeroengine life management system, so as to further realize the calculation of part life damage and enable the life management system to perform its due functions.

[0042] The present invention can calculate the stress of aeroengine parts at each moment of flight in a very short time, so that the calculation of part life damage can meet the requirements of the aeroengine life management system for airborne calculation and ground calculation in terms of time, enabling the aeroengine life management system to function normally, and further improving the safety, reliability, maintainability and economy of the aeroengine. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to make the content of the present invention easier to be clearly understood, the present invention will be further described in detail below according to the specific embodiments of the present invention in conjunction with the drawings.

[0044] Figure 1 It is a schematic diagram of the airborne system of the existing aeroengine life management system.

[0045] Figure 2 It is a schematic diagram of the ground system of the existing aeroengine life management system.

[0046] Figure 3 It is a schematic diagram of the stress distribution and assessment point of a certain stage of turbine blade.

[0047] Figure 4 It is a schematic diagram of the stress distribution and assessment point of a certain stage of axial flow compressor disk.

[0048] Figure 5 It is a flowchart of the stress calculation method based on the airborne life management system.

[0049] Figure 6 It is a flowchart of a life prediction method based on an airborne life management system. Specific implementation mode

[0050] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the specific embodiments cited are not intended to limit the present invention.

[0051] Embodiment 1:

[0052] Combined with Figures 3 - 5 , a stress calculation method based on an airborne life management system, characterized by including the following steps:

[0053] Step S1: Select the point with the maximum stress or the minimum safety factor in the components of the engine as the assessment point; among them, the components of the engine include multiple parts, and the multiple parts are multi-stage turbine blades, multi-stage turbine disks, multi-stage compressor blades, and multi-stage compressor disks;

[0054] Step S2: Run the engine, and record multiple groups of data as time increases, where each group of data includes the rotational speed and temperature of each part in the components of the engine;

[0055] Step S3: Process the multiple groups of data differently according to different application environments of the engine, and calculate the equivalent stress of the preset assessment point of each part at any moment;

[0056] Among them, when the engine is in the first application environment, obtain the first equivalent stress corresponding to the design value of the initial rotational speed of the gas turbine rotor or the design value of the initial rotational speed of the power turbine, and calculate the equivalent stress of the preset assessment point of each part in each group of data according to the first equivalent stress;

[0057] When the engine is in the second application environment, set multiple working conditions, and each working condition considers any one of the centrifugal load, temperature load, and aerodynamic load. For different working conditions, perform stress calculations on the preset assessment point, respectively obtain the stress components of the preset assessment point, and calculate the equivalent stress of the preset assessment point of each part in each group of data according to the stress components.

[0058] The above provides a stress calculation method based on an airborne life management system, which can calculate the stress of aero-engine parts at each moment of flight in a very short time, so that the calculation of part life damage can meet the requirements of the airborne calculation and ground calculation of the aero-engine life management system in terms of time.

[0059] In this embodiment, the first application environment is the application environment before the engine bench test and type approval, and the second application environment is the application environment during user verification.

[0060] In this embodiment, when the engine is in the first application environment, the equivalent stress corresponding to the designed value of the gas turbine rotor speed or the designed value of the power turbine speed is obtained, and the formula for calculating the equivalent stress of the assessment points of each part in each group of data according to the equivalent stress is as follows:

[0061]

[0062] In the formula: S is the equivalent stress of the assessment point, Sk is the first equivalent stress corresponding to the designed value of the gas turbine rotor speed or the designed value of the power turbine speed, N is the actual value of the gas turbine rotor speed or the actual value of the power turbine speed corresponding to each group of data, and N100 is the designed value of the gas turbine rotor speed or the designed value of the power turbine speed.

[0063] In this embodiment, the method for calculating the stress of the preset assessment points under different working conditions is as follows:

[0064] (1) If the working condition is that the designed speed of the gas turbine rotor speed or the power turbine speed is set to the rated speed, calculate the centrifugal load by finite element calculation; (2) If the working condition is that the temperature before the power turbine speed takes the rated temperature, calculate the temperature load by the aerodynamic design method; (3) If the working condition is that the temperature before the power turbine speed takes 80% of the rated temperature, calculate the temperature load by the aerodynamic design method; (4) If the working condition is that the designed speed of the gas turbine rotor speed or the power turbine speed is 80% of the rated speed, calculate the aerodynamic load by the aerodynamic design method; (5) If the working condition is that the designed speed of the gas turbine rotor speed or the power turbine speed is 80% of the rated speed, calculate the aerodynamic load by the aerodynamic design method.

[0065] Among them, in the second working condition, the method for calculating the temperature load is as follows: Obtain the rated value of the temperature before the power turbine speed, and calculate the first actual temperature value corresponding to the rated value and the second actual temperature value corresponding to the reduction value according to the rated value of the temperature before the power turbine speed and the reduction value of the flight parameters of the temperature before the power turbine speed respectively; Calculate the actual temperature value of the assessment points of each part in each group of data according to the first actual temperature value and the second actual temperature value.

[0066] Specifically, when the engine is in the second working state, the formula for calculating the equivalent stress of the assessment points of each part in each group of data according to the stress components is as follows:

[0067]

[0068] In the formula: S n is the stress component, S1 nis the nth stress component of the first working condition, N is the actual value of the gas turbine rotor speed or the actual value of the power turbine speed corresponding to each group of data, N100 is the designed value of the gas turbine rotor speed or the designed value of the power turbine speed, B n0 is the first correction coefficient of the nth stress component, B n1 is the second correction coefficient of the nth stress component, T is the T45 temperature value of each group of data, B n2 is the third correction coefficient of the nth stress component, B n3 is the fourth correction coefficient of the nth stress component, S 2n is the nth stress component of the second working condition, S 3n is the nth stress component of the third working condition, T100 is the rated value of the T45 speed, T80 is the first reduction value of the T45 speed, B m1 is the second correction coefficient of the nth stress component, B n2 is the third correction coefficient of the nth stress component, B n3 is the fourth correction coefficient of the nth stress component, S n4 is the nth stress component of the fourth working condition, S 5n is the nth stress component of the fifth working condition, S e is the equivalent stress at the assessment point.

[0069] Among them, there are six stress components, and the six stress components are the normal stress in the x direction, the normal stress in the y direction, the normal stress in the z direction, the shear stress in the xy direction, the shear stress in the yz direction, and the shear stress in the zx direction.

[0070] n = 1, 2, 3, 4, 5, 6 are the 6 stress component numbers, which are respectively expressed as: normal stresses in the x, y, and z directions (σ x , σ y , σ z ), shear stresses in the xy, yz, and zx directions (τ xy , τ yz , τ zx ).

[0071] For example, S 11 , represents the 1st stress component of the first working condition: the normal stress σ x in the x direction; and for another example, S 34 , represents the 4th stress component of the third working condition: the shear stress τ xy in the xy direction, and so on.

[0072] Example 2:

[0073] As Figure 6 shown, based on Example 1, a life prediction method based on an airborne life management system includes the following steps:

[0074] Step S1: Select the point with the maximum stress or the minimum safety factor among the components of the engine as the assessment point; among them, the components of the engine include multiple parts, and the multiple parts are multi-stage turbine blades, multi-stage turbine disks, multi-stage compressor blades, and multi-stage compressor disks;

[0075] Step S2: Run the engine and record multiple sets of data as time increases. Among them, each set of data includes the rotational speed and temperature of each part in the components of the engine;

[0076] Step S3: Process the multiple sets of data differently according to different application environments of the engine, and calculate the equivalent stress of the preset assessment point at any moment of each part;

[0077] Step S4: Process each set of data differently according to different application environments of the engine, and calculate the actual temperature value of the preset assessment point.

[0078] The above provides a life prediction method based on an airborne life management system. According to the obtained equivalent stress of the preset assessment point at any moment of each part and the actual temperature value of the preset assessment point, the calculation of part life damage is further realized, enabling the life management system to perform its due functions.

[0079] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0080] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for realizing the functions specified in one process Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0081] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to work in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction device that implements the functions specified in one or more of the processes and / or blocks Figure 1 in one or more of the processes and / or blocks Figure 1 specified in the block or blocks.

[0082] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus, such that a series of operational steps are performed on the computer or other programmable apparatus to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more of the processes and / or blocks Figure 1 in one or more of the processes and / or blocks Figure 1 specified in the block or blocks.

[0083] Obviously, the above-described embodiments are merely examples given for clear illustration and are not limitations on the implementation. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. The obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A stress calculation method based on an airborne life management system, characterized in that It includes the following steps: Step S1: Select the point with the maximum stress or the minimum safety factor in the components of the engine as the assessment point; among them, the components of the engine include multiple parts, and the multiple parts are multi-stage turbine blades, multi-stage turbine disks, multi-stage compressor blades, and multi-stage compressor disks; Step S2: Run the engine, and record multiple groups of data as time increases. Among them, each group of data includes the rotational speed and temperature of each part in the components of the engine; Step S3: Perform different processing on multiple groups of data according to different application environments of the engine, and calculate the equivalent stress of the preset assessment point at any moment of each part; Among them, when the engine is in the first application environment, obtain the first equivalent stress corresponding to the design value of the initial rotational speed of the gas turbine rotor or the design value of the initial rotational speed of the power turbine, and calculate the equivalent stress of the preset assessment point of each part in each group of data according to the first equivalent stress; When the engine is in the second application environment, set multiple working conditions, and each working condition considers any one of the centrifugal load, temperature load, and aerodynamic load. For different working conditions, perform stress calculation on the preset assessment point, and respectively obtain the stress components of the preset assessment point, and calculate the equivalent stress of the preset assessment point of each part in each group of data according to the stress components; The method for performing stress calculation on the preset assessment point for different working conditions is as follows: If the working condition is to set the design rotational speed of the gas turbine rotor or the power turbine rotor to the rated rotational speed, calculate the centrifugal load through finite element; if the working condition is that the temperature before the power turbine takes the rated temperature, use the aerodynamic design method to calculate the temperature load; if the working condition is that the temperature before the power turbine takes 80% of the rated temperature, use the aerodynamic design method to calculate the temperature load; if the working condition is that the design rotational speed of the gas turbine rotor or the power turbine rotor is 80% of the rated rotational speed, use the aerodynamic design method to calculate the aerodynamic load; if the working condition is that the design rotational speed of the gas turbine rotor or the power turbine rotor is 80% of the rated rotational speed, use the aerodynamic design method to calculate the aerodynamic load.

2. The stress calculation method based on the airborne life management system according to claim 1, characterized in that: In the second working condition, the method for calculating the temperature load is as follows: Obtain the rated value of the temperature before the power turbine rotational speed, and calculate the first actual temperature value corresponding to the rated value and the second actual temperature value corresponding to the reduction value respectively according to the rated value of the temperature before the power turbine and the reduction value of the flight parameters of the temperature before the power turbine; Calculate the actual temperature value of the assessment point of each part in each group of data according to the first actual temperature value and the second actual temperature value.

3. The stress calculation method based on the airborne life management system according to claim 2, wherein: The reduction coefficient of the reduction value is 0.8 or 0.88 or 0.

76.

4. The stress calculation method based on the airborne life management system according to claim 1, wherein: When the engine is in the first application environment, obtain the equivalent stress corresponding to the design value of the gas turbine rotor rotational speed or the design value of the power turbine rotational speed, and the formula for calculating the equivalent stress of the assessment point of each part in each group of data according to the equivalent stress is as follows: In the formula: S is the equivalent stress of the assessment point, Sk is the first equivalent stress corresponding to the design value of the gas turbine rotor rotational speed or the design value of the power turbine rotational speed, N is the actual value of the gas turbine rotor rotational speed or the actual value of the power turbine rotational speed corresponding to each group of data, and N100 is the design value of the gas turbine rotor rotational speed or the design value of the power turbine rotational speed.

5. The stress calculation method based on the airborne life management system according to claim 1, wherein: When the engine is in the second working state, multiple working conditions are set, and each working condition considers one of the centrifugal load, temperature load, and aerodynamic load. For different working conditions, the finite element method is used to calculate the stress of the parts to be evaluated, and the stress components of the evaluation points are obtained respectively. The formula for calculating the equivalent stress of the evaluation points of each part in each group of data according to the stress components is as follows: Where: S n is the stress component, S1 n is the nth stress component under the first working condition, N is the actual value of the gas turbine rotor speed or the actual value of the power turbine speed corresponding to each group of data, N100 is the design value of the gas turbine rotor speed or the design value of the power turbine speed, B n0 is the first correction coefficient of the nth stress component, B n1 is the second correction coefficient of the nth stress component, T is the T45 temperature value of each group of data, B n2 is the third correction coefficient of the nth stress component, B n3 is the fourth correction coefficient of the nth stress component, S 2n is the nth stress component under the second working condition, S 3n is the nth stress component under the third working condition, T100 is the rated value of the T45 temperature, T80 is the first reduction value of the T45 temperature, B m1 is the second correction coefficient of the nth stress component, B n2 is the third correction coefficient of the nth stress component, B n3 is the fourth correction coefficient of the nth stress component, S n4 is the nth stress component under the fourth working condition, S 5n is the nth stress component under the fifth working condition, S e is the equivalent stress at the assessment point.

6. The stress calculation method based on the airborne life management system according to claim 1, characterized in that: In step S3, there are six stress components, and the six stress components are the normal stress in the x direction, the normal stress in the y direction, the normal stress in the z direction, the shear stress in the xy direction, the shear stress in the yz direction, and the shear stress in the zx direction respectively.

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