A method for allocating reliability indexes of aero-engines based on prior data

Abstract

This application belongs to the field of aero-engine reliability design, and particularly relates to a method for allocating aero-engine reliability indexes based on prior data. The method includes: Step 1, constructing a basic reliability model of the engine, where the basic reliability model of the engine includes each component and / or system that makes up the engine; Step 2, constructing a reliability index allocation model; Step 3, determining the numerical values of each parameter in the reliability index allocation model; Step 4, inputting the numerical values of each parameter into the reliability index allocation model and calculating the reliability index allocation results of each component and / or system in the basic reliability model of the engine. Based on prior data such as verification data during the development stage of this model, verification data during the development stage of similar models, and in-service data of similar models, this application constructs a reliability index allocation model considering the correction coefficient of similar models and the structure correction coefficient, realizes index allocation, and improves the accuracy of aero-engine reliability index allocation.

Description

Technical Field

[0001] This application belongs to the field of aero-engine reliability design, and particularly relates to a method for allocating aero-engine reliability indexes based on prior data. Background Art

[0002] The reliability index of an aero-engine is an important index in engine development and one of the reliability indexes that users particularly concern. Usually, quantitative reliability index requirements are put forward through the overall development requirements during the engine demonstration phase. During the engine development process, this index is decomposed into component systems to guide the reliability design of component systems. During the qualification and type approval phases, this index is evaluated. Reliability is an inherent property of the engine and is directly related to the engine design scheme. The rationality of the reliability index allocation result directly affects the selection of the component system design scheme and the evaluation during the qualification and type approval phases.

[0003] The existing methods for allocating aero-engine reliability indexes mainly adopt the methods recommended by national military standards, mainly including equal allocation method, proportional combination method, expert scoring method, etc. The main disadvantages are: first, the engineering applicability of the general standard method is not strong; second, the combination with model development data and similar model data is not tight, and the rationality and dynamic adjustability of the allocation are poor.

[0004] Therefore, there is an urgent need for a technical solution to overcome or mitigate at least one of the above defects of the existing technology. Summary of the Invention

[0005] The purpose of this application is to provide a method for allocating aero-engine reliability indexes based on prior data to solve at least one problem existing in the existing technology.

[0006] The technical solution of this application is as follows:

[0007] A method for allocating aero-engine reliability indexes based on prior data, comprising:

[0008] Step 1, construct a basic engine reliability model, where the basic engine reliability model includes each component and / or system that makes up the engine;

[0009] Step 2, construct a reliability index allocation model, where the reliability index allocation model includes:

[0010] MTBF allocation sub-model:

[0011] ;

[0012] ;

[0013] MTBF conversion sub-model:

[0014] ;

[0015] ;

[0016] ;

[0017] wherein, is the proportion of on-site use failures of the i-th component and / or system, is the proportion of failures during the development stage of the i-th component and / or system, is the similarity model correction factor of the i-th component and / or system, is the structural correction factor of the i-th component and / or system, is the failure rate of the i-th component and / or system, is the overall engine failure rate, is the mean time between failures of the i-th component and / or system, is the overall engine mean time between failures, n is the number of components and / or systems that make up the engine;

[0018] Step 3, determine the values of each parameter in the reliability index allocation model;

[0019] Step 4, input the values of each parameter into the reliability index allocation model, and calculate the reliability index allocation results of each component and / or system in the basic engine reliability model.

[0020] In at least one embodiment of the present application, in Step 1, constructing the basic engine reliability model includes:

[0021] Construct the basic engine reliability model according to preset model simplification rules, and the model simplification rules are:

[0022] Each component and / or system that makes up the engine is independent of each other during failure;

[0023] The failure rates of each component and / or system that makes up the engine are all constants, and the lifetimes of each component and / or system that makes up the engine all follow an exponential distribution;

[0024] Each component and / or system that makes up the engine is connected in series.

[0025] In at least one embodiment of the present application, in Step 1, the basic engine reliability model includes:

[0026] A mechanical system, a fuel and control system, and a health management system connected in series with the main engine;

[0027] A fan, a high-pressure compressor, a main combustor, a high-pressure turbine, a low-pressure turbine, an afterburner, a nozzle, an outer casing, and an external structure connected in series with the host.

[0028] In at least one embodiment of the present application, in step three, determining the values of the various parameters in the reliability index allocation model includes:

[0029] Determining the value of the failure proportion of each component and / or system in the research and development stage of the reliability index allocation model;

[0030] Determining the value of the similarity model correction coefficient of each component and / or system in the reliability index allocation model;

[0031] Determining the value of the structure correction coefficient of each component and / or system in the reliability index allocation model;

[0032] Obtaining the mean time between failures of the entire engine in the preset reliability index allocation model.

[0033] In at least one embodiment of the present application, determining the value of the failure proportion of each component and / or system in the research and development stage of the reliability index allocation model includes:

[0034] Obtaining the failure information in the research and development stage of the present model;

[0035] Statistically calculating the ratio of the failures of each component and / or system to the failures of the entire engine from the failure information in the research and development stage of the present model to obtain the value of the failure proportion of each component and / or system in the research and development stage.

[0036] In at least one embodiment of the present application, determining the value of the similarity model correction coefficient of each component and / or system in the reliability index allocation model includes:

[0037] Obtaining the failure information in the research and development stage of the similar model and the failure information of the similar model in the field operation;

[0038] Statistically calculating the failure proportion of each component and / or system in the research and development stage and the failure proportion in the field operation stage from the failure information in the research and development stage of the similar model and the failure information of the similar model in the field operation;

[0039] Calculating the ratio of the failure proportion of each component and / or system in the field operation stage to the failure proportion in the research and development stage to obtain the value of the similarity model correction coefficient of each component and / or system.

[0040] In at least one embodiment of the present application, determining the value of the structure correction coefficient of each component and / or system in the reliability index allocation model includes:

[0041] Obtain the numerical values of the structural correction factors for each component and / or system according to the preset rules for obtaining the structural correction factors.

[0042] In at least one embodiment of the present application, formulate the rules for obtaining the structural correction factors based on the influence of structure, material, process, failure characteristics, and sufficiency of verification on the reliability index.

[0043] In at least one embodiment of the present application, in step four, input the numerical values of each parameter into the reliability index allocation model, and calculate the failure rate and mean time between failures of each component and / or system.

[0044] The invention has at least the following beneficial technical effects:

[0045] The method for allocating the reliability index of an aero-engine based on prior data in the present application constructs a reliability index allocation model considering the correction factor of similar models and the structural correction factor based on prior data such as the verification data in the development stage of this model, the verification data in the development stage of similar models, and the field usage data of similar models, realizes index allocation, and improves the accuracy of allocating the reliability index of an aero-engine. Description of the Drawings

[0046] Figure 1 is a flowchart of the method for allocating the reliability index of an aero-engine based on prior data in an embodiment of the present application;

[0047] Figure 2 is a schematic diagram of the basic reliability model of an engine in an embodiment of the present application. Detailed Embodiment

[0048] To make the purpose, technical solution, and advantages of the implementation of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present application. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0049] In the description of this application, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of this application.

[0050] The following will further elaborate on this application in conjunction with the attached Figures 1 to 2 drawings.

[0051] This application provides a method for allocating reliability indicators of an aero-engine based on prior data, as Figure 1 shown, which includes the following steps:

[0052] Step 1: Construct a basic reliability model of the engine. The basic reliability model of the engine includes each component and / or system that makes up the engine;

[0053] Step 2: Construct a reliability indicator allocation model;

[0054] Step 3: Determine the values of each parameter in the reliability indicator allocation model;

[0055] Step 4: Input the values of each parameter into the reliability indicator allocation model and calculate the reliability indicator allocation results of each component and / or system in the basic reliability model of the engine.

[0056] The method for allocating reliability indicators of an aero-engine based on prior data in this application constructs a basic reliability model of the engine in a series mode. During the engine development process, based on the preliminary verification of the engine, a reliability indicator allocation model considering the correction coefficient of similar models and the structure correction coefficient is constructed based on prior data such as the verification data in the development stage of this model, the verification data in the development stage of similar models, and the field usage data of similar models. The principle for determining the correction coefficient is given, the values of each parameter in the model are determined, and the indicator allocation is completed.

[0057] In the preferred embodiment of this application, the allocation of the mean time between failures (MTBF) indicator of the engine is used for illustration, and other reliability indicators can be referred to for implementation. Specifically, in Step 1, when allocating the MTBF indicator of the engine, to simplify the problem, a basic reliability model of the engine is constructed according to the preset model simplification rules. The model simplification rules generally include the following assumptions:

[0058] Each component and / or system that makes up the engine is independent of each other during failure;

[0059] The failure rates of the components and / or systems that make up the engine are all constants, and the lifetimes of the components and / or systems that make up the engine all follow an exponential distribution;

[0060] The components and / or systems that make up the engine are connected in series.

[0061] Based on the above assumptions, a basic reliability model of the engine is constructed by the reliability block diagram method, as Figure 2 shown. The basic reliability model of the engine includes:

[0062] A mechanical system, a fuel and control system, and a health management system connected in series with the main engine;

[0063] A fan, a high-pressure compressor, a main combustion chamber, a high-pressure turbine, a low-pressure turbine, an afterburner, a nozzle, an outer casing, and an external structure connected in series with the main engine.

[0064] For the situation where the engine has completed preliminary verification and some reliability data has been accumulated, based on the verification data in the development stage of this model and the usage data of similar models, a reliability index allocation model considering the correction factors of similar models and structural correction factors is constructed as follows:

[0065] MTBF allocation sub-model:

[0066] ;

[0067] ;

[0068] MTBF conversion sub-model:

[0069] ;

[0070] ;

[0071] ;

[0072] Among them, is the proportion of on-site usage failures of the i-th component and / or system, is the proportion of failures in the development stage of the i-th component and / or system, is the correction factor of the similar model of the i-th component and / or system, is the structural correction factor of the i-th component and / or system, is the failure rate of the i-th component and / or system, is the failure rate of the whole engine, is the mean time between failures of the i-th component and / or system, is the mean time between failures of the whole engine, n is the number of components and / or systems that make up the engine.

[0073] In a preferred embodiment of the present application, according to the reliability index allocation model obtained above, in step three, determine the values of each parameter in the reliability index allocation model, including:

[0074] Determine the value of the failure proportion of each component and / or system in the development stage in the reliability index allocation model;

[0075] Determine the value of the similarity model correction coefficient of each component and / or system in the reliability index allocation model;

[0076] Determine the value of the structure correction coefficient of each component and / or system in the reliability index allocation model;

[0077] Obtain the mean time between failures of the entire engine in the preset reliability index allocation model.

[0078] In this embodiment, determining the value of the failure proportion of each component and / or system in the development stage in the reliability index allocation model includes:

[0079] Obtain the failure information in the development stage of this model;

[0080] Statistically analyze the ratio of the failures of each component and / or system to the failures of the entire engine from the failure information in the development stage of this model, and obtain the value of the failure proportion of each component and / or system in the development stage.

[0081] Extract and analyze the failure information in the development stage of this model from the verification data in the development stage of this model, and obtain the failure proportion of each component and / or system in the development stage as the input of the MTBF allocation sub-model.

[0082] In this embodiment, determining the value of the similarity model correction coefficient of each component and / or system in the reliability index allocation model includes:

[0083] Obtain the failure information in the development stage of the similar model and the failure information of the similar model in the field use;

[0084] Statistically analyze the failure proportion of each component and / or system in the development stage and the failure proportion in the field use stage from the failure information in the development stage of the similar model and the failure information of the similar model in the field use;

[0085] Calculate the ratio of the failure proportion of each component and / or system in the field use stage to the failure proportion in the development stage, and obtain the value of the similarity model correction coefficient of each component and / or system.

[0086] Identify models with similar configurations to this model. The similar models should have a similar structural layout to this model and have in-service data. Extract the fault information of the similar models during the development stage from the verification data of the similar models during the development stage, and extract the in-service fault information of the similar models from the in-service data of the similar models for analysis to obtain the correction factors of the similar models for each component and / or system. The numerical value of this correction factor characterizes the difference between in-service and out-of-service use.

[0087] In this embodiment, the numerical values of the structural correction factors for each component and / or system are obtained according to the preset rules for taking values of the structural correction factors. Preferably, the rules for taking values of the structural correction factors are formulated based on the effects of structure, material, process, fault characteristics, and verification sufficiency on the reliability index.

[0088] Based on dimensions such as the adoption of new structures, new materials, and new processes in the engine, the characteristics of potential fault modes of relevant structures, and the sufficiency of verification, considering the impact of the structure and usage characteristics of this model on the allocation of the engine MTBF index, determine the structural correction factors for each component and / or system. . Combining engineering experience, take values between 0 and 2. For the rules for taking values of the structural correction factors, refer to Table 1.

[0089] Table 1

[0090]

[0091] Finally, in step four, input the proportions of faults during the development stage of each component and / or system obtained in the above manner , the correction factors of the similar models of each component and / or system , and the structural correction factors of each component and / or system into the MTBF allocation sub-model to calculate the proportions of in-service faults of each component and / or system ; input the numerical value of the preset average time between failures of the entire engine into the MTBF conversion sub-model to calculate the failure rate of the entire engine ; input the proportions of in-service faults of each component and / or system , and the failure rate of the entire engine into the MTBF allocation sub-model to calculate the failure rates of each component and / or system , and then calculate the average time between failures of each component and / or system according to the MTBF conversion sub-model .

[0092] In an embodiment of the present application, the required value of the MTBF index of a certain aero-engine is 160 hours, that is, the given average time between failures of the entire engine It is 160 hours. The reliability index is allocated during the development stage according to the method of this application. For the sake of simplicity in description, in this embodiment, the process of allocating the engine MTBF index to the main engine, mechanical system, fuel and control system is taken as an example for detailed description. Other components and / or systems in the basic reliability model of the engine can be allocated in the same way according to this method and will not be described separately.

[0093] First, construct the basic reliability model of the engine and the reliability index allocation model according to the methods in Steps 1 and 2. In Step 3, analyze the fault information verified at the current stage of this model type, and determine the proportion of faults in the development stage of the main engine, mechanical system, fuel and control system. The results are shown in Table 2.

[0094] Table 2

[0095]

[0096] Determine a model type that is similar in configuration to this model type and has field usage data. According to the verification data in the development stage of the similar model type and the field usage data of the similar model type, respectively count the proportion of faults in the development stage and the proportion of faults in field usage of the main engine, mechanical system, fuel and control system, and calculate the correction coefficient of the similar model type. The results are shown in Table 3.

[0097] Table 3

[0098]

[0099] Furthermore, determine the structure correction coefficients of the main engine, mechanical system, fuel and control system according to the structure correction coefficient value-taking rules. The results are shown in Table 4.

[0100] Table 4

[0101]

[0102] In Step 4, calculate the proportion of faults in field usage of the main engine, mechanical system, fuel and control system. The results are shown in Table 5.

[0103] Table 5

[0104]

[0105] Finally, calculate the allocated failure rates and mean time between failures of the main engine, mechanical system, fuel and control system.

[0106] Main engine:

[0107] ;

[0108] (hours);

[0109] Mechanical system:

[0110] ;

[0111] (hour);

[0112] Fuel and control system:

[0113] ;

[0114] (hour);

[0115] Through the above steps, the MTBF index of the engine is allocated to the main engine, mechanical system, and fuel and control system.

[0116] The method for allocating the reliability index of an aero-engine based on prior data in this application is closely combined with the actual engineering requirements of aero-engines, and has stronger engineering applicability; it makes full use of prior data such as verification data in the development stage of this model, verification data in the development stage of similar models, and field use data of similar models, and at the same time considers the differential correction of in-field verification and out-field use as well as the structural feature correction, making the allocation of reliability indexes more reasonable and accurate; through the application of this method, the ability to allocate the reliability index of aero-engines is improved, the association between the allocation of reliability indexes and prior data in the development stage is realized, and by improving the accuracy of the allocation results of reliability indexes, the reliability improvement of components and / or systems in the development stage is supported.

[0117] The above is only the specific implementation manner of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in this application should be covered within the protection scope of this application. Therefore, the protection scope of this application should be subject to the protection scope of the claimed rights.

Claims

1. A method for allocating reliability indexes of an aero-engine based on prior data, characterized in that Including: Step 1: Construct a basic reliability model of the engine, where the basic reliability model of the engine includes each component and / or system that makes up the engine; Step 2: Construct a reliability index allocation model, where the reliability index allocation model includes: MTBF allocation sub-model: P i = P i d × K 1i × K 2i λ i = λ s × P i MTBF conversion sub-model: Among them, P i is the proportion of in-service failures of the i-th component and / or system, P i d is the proportion of failures during the development stage of the i-th component and / or system, K 1i is the similarity model correction factor of the i-th component and / or system, K 2i is the structure correction factor of the i-th component and / or system, λ i is the failure rate of the i-th component and / or system, λ s is the failure rate of the entire engine, MTBF i is the mean time between failures of the i-th component and / or system, MTBF S is the mean time between failures of the entire engine, and n is the number of components and / or systems that make up the engine; Step 3: Determine the values of each parameter in the reliability index allocation model, including: Determine the values of the proportion of faults in the development stage of each component and / or system in the reliability index allocation model; Determine the values of the similarity model correction coefficients of each component and / or system in the reliability index allocation model, including: Obtain the fault information in the development stage of the similar model and the fault information in the field use of the similar model; Statistically analyze the proportion of faults in the development stage and the proportion of faults in the field use stage of each component and / or system from the fault information in the development stage of the similar model and the fault information in the field use of the similar model; Calculate the ratio of the proportion of faults in the field use stage to the proportion of faults in the development stage of each component and / or system to obtain the values of the similarity model correction coefficients of each component and / or system; Determine the values of the structure correction coefficients of each component and / or system in the reliability index allocation model; Obtain the mean time between failures of the engine as a whole preset in the reliability index allocation model; Step 4: Input the values of each parameter into the reliability index allocation model and calculate the reliability index allocation results of each component and / or system in the basic reliability model of the engine.

2. The method for allocating reliability indexes of an aero-engine based on prior data according to claim 1, wherein In Step 1, constructing the basic reliability model of the engine includes: Construct the basic reliability model of the engine according to the preset model simplification rules, where the model simplification rules are: Each component and / or system that makes up the engine is independent of each other during a fault; The failure rates of each component and / or system that makes up the engine are all constants, and the lifetimes of each component and / or system that makes up the engine all follow an exponential distribution; Each component and / or system that makes up the engine is connected in series.

3. The method for allocating reliability indexes of an aeroengine based on prior data according to claim 2, characterized in that In Step 1, the basic reliability model of the engine includes: A mechanical system, a fuel and control system, and a health management system connected in series with the main engine; A fan, a high-pressure compressor, a main combustion chamber, a high-pressure turbine, a low-pressure turbine, an afterburner, a nozzle, an outer casing, and an external structure connected in series with the main engine.

4. The method for allocating the reliability index of an aero-engine based on prior data according to claim 3, characterized in that Determining the values of the proportion of faults in the development stage of each component and / or system in the reliability index allocation model includes: Obtain the fault information in the development stage of this model; Statistically analyze the ratio of the faults of each component and / or system to the faults of the engine as a whole from the fault information in the development stage of this model to obtain the values of the proportion of faults in the development stage of each component and / or system.

5. The method for allocating reliability indexes of an aero-engine based on prior data according to claim 4, characterized in that Determining the values of the structure correction coefficients of each component and / or system in the reliability index allocation model includes: Obtain the values of the structure correction coefficients of each component and / or system according to the preset structure correction coefficient value-taking rules.

6. The method for allocating reliability indexes of an aero-engine based on prior data according to claim 5, wherein Formulate the structure correction coefficient value-taking rules based on the influence of structure, material, process, fault characteristics, and the sufficiency of verification on the reliability index.

7. The method for allocating the reliability index of an aero-engine based on prior data according to claim 6, characterized in that, In Step 4, input the numerical values of the respective parameters into the reliability index allocation model to calculate the failure rates and mean time between failures of each component and / or system.

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