Method and system for compiling multi-mode multi-danger point acceleration task test drive spectrum

Abstract

The application discloses a kind of multi-mode multi-dangerous point's acceleration task test flight spectrum compilation method and system considering, belong to aero-engine acceleration task test flight spectrum technical field, comprising: the stress and temperature distribution of acquisition component under different load, working condition;Select the key characteristics of multiple component operation Check point as potential dangerous point for analysis;The fatigue and creep damage of each check point selected is calculated and evaluated respectively;Statistical analysis of the speed change rate distribution characteristics in long-term life test flight spectrum, determine the slow car state to maximum state switching rate;Compare the damage values of different failure modes of each check point;The multi-mode multi-dangerous point's acceleration task test flight spectrum compilation method and system considering, it is suitable for most military or civilian aero-engine acceleration task test flight spectrum compilation, can accurately reflect the damage state of component in actual service process, provides strong support for the optimization of acceleration task test flight spectrum.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine acceleration mission test spectrum technology, specifically involving a method and system for compiling acceleration mission test spectra that considers multiple modes and multiple danger points. Background Technology

[0002] As complex power systems, aero engines' core components, such as fan disks, turbine disks, turbine blades, and combustion chamber casings, endure extreme conditions like high temperatures, high pressures, and high speeds during operation. This places extremely high demands on their structural strength and fatigue life. To ensure the safety and reliability of these critical components during actual service, they must be tested. However, while traditional long-life test profiles can simulate real-world operating environments, they are time-consuming and costly, making it difficult to meet the demands of modern aero engine development for rapid testing and optimization.

[0003] Accelerated mission testing, as an effective method to shorten testing cycles and accelerate fatigue damage accumulation, has received widespread attention in recent years. Through a well-designed accelerated mission test spectrum, the damage behavior of components during long-term operation can be simulated in a shorter time, thereby significantly reducing testing costs. However, previous accelerated mission testing methods have been relatively limited in their systematic compilation, and the spectrum conditions are often overly idealized, failing to accurately reflect the damage state of components during actual service. Therefore, it is necessary to develop a new accelerated mission test spectrum compilation method and system that considers multiple modes and multiple hazard points to address existing problems. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for compiling acceleration mission test spectrum considering multiple modes and multiple danger points, so as to solve the problem that the acceleration mission test spectrum compilation method is too idealistic.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for compiling an acceleration mission test spectrum considering multiple modes and multiple hazard points, comprising the following steps:

[0006] Step 1: Perform stress simulation analysis on the components of the research object. Through simulation analysis, obtain the stress and temperature distribution of the components under different loads and working conditions, thereby determining its key stress areas and potential weak points.

[0007] Step Two: Select several representative assessment points as potential hazards for in-depth analysis; the selection of assessment points is based on the key characteristics of components during operation; through the reasonable selection of assessment points, the test run spectrum can be ensured to be more reasonable and practical.

[0008] Step 3: Using Miner's linear cumulative damage theory, fatigue and creep damage are calculated and evaluated for each selected assessment point. Specifically, for each assessment point, based on the stress changes during the working cycle, fatigue damage is first calculated to assess the degree of cumulative material damage caused by cyclic loading. Then, creep damage is further calculated based on the temperature and stress levels of the assessment point.

[0009] Step 4: The thermal shock load in the engine comes from temperature changes. The rate of temperature change largely depends on the rate of change of engine speed. When compiling the acceleration test spectrum, the peak and valley temperatures are guaranteed by the engine speed in the idle-maximum-idle cycle. Therefore, in order to ensure the thermal shock damage is equivalent, the distribution characteristics of the rate of change of engine speed in the long-term life test spectrum are statistically analyzed to determine the switching rate from idle state to maximum state.

[0010] Step 5: Compare the damage values ​​of different failure modes at each assessment point, select the assessment point with the maximum fatigue damage value and convert it into the number of slow-maximum-slow cycle times of the acceleration spectrum, and select the assessment point with the maximum creep damage value and convert it into the maximum state holding time.

[0011] Step Six: Based on the number of slow-maximum-slow cycle counts, maximum state holding time, and slow-maximum state switching rate obtained from the above steps, compile a comprehensive test spectrum for the Gas mission that considers multiple assessment points.

[0012] Step 7: Perform damage consistency verification between the accelerated mission test spectrum, which takes into account multiple modes and multiple hazard points, and the original long-term life test spectrum.

[0013] Preferably, in step two, the selection of assessment points may include the following categories: first, the point of maximum stress; second, the point of maximum temperature; in addition, locations where stress and temperature are both high can be selected as assessment points to comprehensively evaluate the performance of components under complex working conditions.

[0014] Preferably, in step three, the Miner linear rule is used to calculate fatigue damage at each assessment point. In the formula n i For a certain stress level, the number of cycles, N i This represents the number of cycles required until failure occurs at this stress level; creep damage is similarly represented by this number of cycles. Calculate, where t i t is the holding time under a certain load level. ci This represents the time required for creep rupture under this load level.

[0015] Preferably, in step five, the fatigue damage value and creep damage value of each assessment point are compared comprehensively, and the assessment point with the largest fatigue damage value is used to convert the number of slow-maximum-slow cycle times in the acceleration spectrum. In the formula D I-M-I Fatigue damage is measured in a single idle-maximum-idle cycle. Preferably, the assessment point with the greatest creep damage is used to convert the maximum state holding time of the acceleration spectrum. In the formula D M This represents creep damage per unit time under maximum conditions.

[0016] Preferably, in step seven, to verify the consistency of damage between the accelerated mission test spectrum and the long-term life test spectrum compiled with multiple modes and multiple hazard points, the load on the test section of the smooth test piece is corrected by a temperature correction factor: S(T0) = S(T)·σ. b (T0) / σ b (T), S(T0), and S(T) represent the stresses at temperatures T0 and T, respectively; σ b (T0), σ b (T) represents the tensile strength at temperatures T0 and T, respectively. A variable cross-section test specimen was designed, and the results of accelerated spectrum and long spectrum tests were compared.

[0017] The present invention also provides an acceleration mission test spectrum compilation system that considers multiple modes and multiple hazard points, comprising:

[0018] The acquisition module is used to acquire the stress and temperature distribution of components under different loads and operating conditions;

[0019] The selection module is used to select key performance indicators of multiple components during operation as potential hazards for analysis.

[0020] The calculation and evaluation module is used to calculate and evaluate fatigue and creep damage for each selected assessment point.

[0021] The statistical analysis module is used to statistically analyze the distribution characteristics of the speed change rate in the long-term life test spectrum and determine the switching rate from idle state to maximum state.

[0022] The comparison module is used to compare the damage values ​​of different failure modes at each assessment point. The assessment point with the maximum fatigue damage is selected and converted into the number of slow-maximum-slow cycle times of the acceleration spectrum. The assessment point with the maximum creep damage is selected and converted into the maximum state holding time.

[0023] The compilation module is used to compile the test spectrum of the acceleration task based on the number of slow-maximum-slow-speed cycles, the maximum state holding time, and the switching rate from slow state to maximum state.

[0024] The testing module is used to verify the consistency of damage between the accelerated mission test spectrum and the long-term life test spectrum.

[0025] The technical effects and advantages of this invention are as follows: This method and system for compiling accelerated mission test spectra considering multiple modes and multiple hazards is simple, intuitive, and has concise steps. It is highly versatile and applicable to the compilation of accelerated mission test spectra for most military or civilian aero engines. It can accurately reflect the damage state of components during actual service, providing strong support for the optimization of accelerated mission test spectra. From the perspective of selecting multiple hazards for assessment, this invention innovates the compilation method for aero-engine accelerated mission test spectra. By proposing a method for compiling accelerated mission test spectra for typical components with multiple modes and multiple hazards, it provides a theoretical basis for the optimization of accelerated mission test spectra compilation methods and has strong applicability. Attached Figure Description

[0026] Figure 1 This is a schematic flowchart of the method of the present invention;

[0027] Figure 2 This is a schematic diagram summarizing the creep damage calculations at various assessment points in the method of this invention;

[0028] Figure 3 This is the long-term life test speed spectrum used in this invention;

[0029] Figure 4 Acceleration spectrum compiled for this invention;

[0030] Figure 5 This is a geometric dimension drawing of the variable cross-section test specimen designed for this invention;

[0031] Figure 6 This is a strain-cycle number curve diagram under the long-term life test spectrum and the compiled accelerated spectrum of the present invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] This invention provides, for example Figure 1 The method for compiling an acceleration mission test spectrum considering multiple modes and multiple hazards, as shown, includes the following steps:

[0034] Step 1: Simulate and analyze the turbine blades made of DZ125 directionally solidified superalloy to obtain their load distribution under different working conditions.

[0035] Step Two: Based on the simulation analysis results in Step One, multiple assessment points were selected to examine the load conditions. These included points with the highest stress values, the highest temperature values, and points with both high stress and high temperature. The selection of points with both high stress and high temperature was based on the simulation analysis results; for example, points where both stress and temperature values ​​exceeded 80% of their maximum values ​​were chosen. The corresponding specific values ​​are shown in the table below.

[0036]

[0037] Step 3: Using Miner's linear cumulative damage theory, calculate fatigue and creep damage for each selected assessment point; the damage calculation results for each assessment point are as follows: Figure 2 As shown;

[0038] Step 4: To ensure that the thermal shock damage in the accelerated life test spectrum and the long-term life test spectrum is equivalent, statistical analysis is performed on the distribution characteristics of the rotational speed change rate in the long-term life test spectrum. The long-term life test spectrum is shown below. Figure 3 As shown; the calculated average time from slow speed to maximum speed is 25.1s, and the average time from maximum speed to slow speed is 23.5s.

[0039] Step 5: Comparison Figure 2 The fatigue damage and creep damage at each assessment point show that the maximum value of fatigue damage occurs at assessment point 1, while the maximum value of creep damage occurs at assessment point 2.

[0040] Based on the principle of damage equivalence, the fatigue damage value at assessment point 1 is used according to... Equivalent calculations were performed to determine the maximum-slow-maximum number of cycles at that point. Simultaneously, based on the creep damage value at assessment point 2, according to... The maximum state time at this point was calculated. Through relevant calculations, the maximum-idle-maximum cycle count that can be converted from the fatigue damage value at test point 1 at 700℃ is 15. At 900℃, all other low-power states are accelerated to equivalent maximum state, and the converted maximum state duration is 2270s.

[0041] Step Six: The converted acceleration mission test spectrum has 15 maximum-idle-maximum cycles, with a maximum state duration of 2270s. Subtracting the maximum state duration contained in the 15 idle-maximum-idle cycles, the concentrated maximum state duration is 1220s. The total acceleration spectrum time is 4045s, the original long-term life test spectrum total time is 6243s, and the acceleration coefficient is 1.54. The compiled acceleration mission test spectrum is as follows: Figure 4 ;

[0042] Step 7: Accelerate the test spectrum and long-term life test spectrum damage consistency verification. The specific operation is as follows:

[0043] Simultaneously, the creep fatigue damage at test points 1 and 2 is simulated in the experiment. The test specimen needs to exhibit different stress and temperature profiles during the experiment. Different stress profiles can be achieved by designing a test specimen with a variable cross-section, thereby changing the cross-sectional area of ​​the test section to achieve the effect of segmented stress.

[0044] Since the temperature in the high-temperature furnace was set to a constant value during the experiment, segmented temperature control was not possible. Therefore, a temperature correction method was considered to convert the stress profile to the same temperature. The temperature correction coefficient was expressed as follows:

[0045]

[0046] The stress profile at test point 1 was converted to the stress at test point 2 at 900℃. A temperature correction factor was used to adjust the specimen load. The conversion method assumed that fatigue creep damage depended on the ratio of stress to the material's tensile strength. Therefore, the stress-corrected specimen design is as follows: Figure 5 As shown;

[0047] S(T0)=S(T)·σ b (T0) / σ b (T)

[0048] To verify the effectiveness of the spectrum compilation method, long-term life test and accelerated test at 700℃ were conducted on the variable cross-section specimen. The test material was DZ125 directionally solidified superalloy. The results of the accelerated test and long-term life test were carried out on a high-temperature electronic creep testing machine, as shown in the table below:

[0049]

[0050]

[0051] The results starting with CS are from the long-term life test spectrum, and the results starting with JS are from the acceleration test spectrum. Analysis of the results shows that the average number of complete cycles under the long-term test spectrum is 34.33, while the average number of complete cycles under the acceleration test spectrum is 33. The average error in the number of complete cycles between the two spectra is -3.87%, indicating that the acceleration test spectrum and the long-term test spectrum have considerable equivalence.

[0052] The strain-cycle curves under accelerated test and long-term life test profiles, considering multiple assessment points, are as follows: Figure 6From the curve shapes, CS-3 and JS-2 almost overlapped throughout the process, while CS-1 and JS-2 showed highly consistent shapes. Regarding the strain rate increases in the accelerated and long-term test spectra, which can be assessed by comparing the curve slopes, the steep increase phase curves of CS-1 and JS-1 were almost parallel, indicating that the cumulative strain rates of the material were comparable under both conditions. In terms of the final strain failure point, the average final failure strain in the long-term life test spectrum was 14.52%, while the average final failure strain in the accelerated test spectrum was 16.01%, representing an error of 10.26% compared to the long-term test spectrum. Multiple factors indicate that the accelerated test spectrum, which considers multiple assessment points, is equivalent in damage to the original long-term life test spectrum.

[0053] In summary, this invention establishes a method for compiling accelerated mission test spectra of typical components, considering multiple modes and multiple hazards, based on the damage risks of key components. This provides a theoretical basis for optimizing the compilation method of accelerated mission test spectra for aero-engines. The method is simple and intuitive, with concise steps and strong versatility, applicable to the compilation of accelerated mission test spectra for most military or civilian aero-engines, and has strong potential for widespread application.

[0054] The present invention also provides an acceleration mission test spectrum compilation system that considers multiple modes and multiple hazard points, comprising:

[0055] The acquisition module is used to acquire the stress and temperature distribution of components under different loads and operating conditions;

[0056] The selection module is used to select key performance indicators of multiple components during operation as potential hazards for analysis.

[0057] The calculation and evaluation module is used to calculate and evaluate fatigue and creep damage for each selected assessment point.

[0058] The statistical analysis module is used to statistically analyze the distribution characteristics of the speed change rate in the long-term life test spectrum and determine the switching rate from idle state to maximum state.

[0059] The comparison module is used to compare the damage values ​​of different failure modes at each assessment point. The assessment point with the maximum fatigue damage is selected and converted into the number of slow-maximum-slow cycle times of the acceleration spectrum. The assessment point with the maximum creep damage is selected and converted into the maximum state holding time.

[0060] The compilation module is used to compile the test spectrum of the acceleration task based on the number of slow-maximum-slow-speed cycles, the maximum state holding time, and the switching rate from slow state to maximum state.

[0061] The testing module is used to verify the consistency of damage between the accelerated mission test spectrum and the long-term life test spectrum.

[0062] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for compiling test spectrums for accelerated missions considering multiple modes and multiple hazard points, characterized in that: include: Obtain the stress and temperature distribution of components under different loads and operating conditions; The key performance points of multiple components during operation were selected as potential hazards for analysis. For each selected assessment point, fatigue and creep damage were calculated and evaluated separately. Statistical analysis of the speed change rate distribution characteristics in the long-term life test spectrum determines the switching rate from idle state to maximum state. By comparing the damage values ​​of different failure modes at each assessment point, the assessment point with the maximum fatigue damage is selected and converted into the number of slow-maximum-slow cycle cycles of the acceleration spectrum, and the assessment point with the maximum creep damage is selected and converted into the maximum state holding time. The test spectrum for acceleration tasks is compiled based on the number of slow-maximum-slow-speed cycles, the maximum state holding time, and the switching rate from slow state to maximum state. Verify the consistency of damage between the accelerated mission test spectrum and the long-term life test spectrum; The key characteristics of the components during operation include: the point of maximum stress, the point of maximum temperature, and the point where both stress and temperature are relatively high. The verification of damage consistency between the accelerated test spectrum and the long-term life test spectrum includes: correcting the load on the test section of the smooth test piece using a temperature correction factor S(T0) = S(T)·σ. b (T0) / σ b (T), where S(T0) and S(T) represent the stresses at temperatures T0 and T, respectively; σ b (T0), σ b (T) represents the tensile strength at temperatures T0 and T, respectively. Based on the correction results, a variable cross-section test specimen was designed, and the results of accelerated spectrum and long spectrum tests were compared.

2. The method for compiling an acceleration mission test spectrum considering multiple modes and multiple hazard points according to claim 1, characterized in that: The process of obtaining the stress and temperature distribution of components under different loads and operating conditions includes: obtaining the stress and temperature distribution of components under different loads and operating conditions through simulation analysis.

3. The method for compiling an acceleration mission test spectrum considering multiple modes and multiple hazard points according to claim 1, characterized in that: The calculation and evaluation of fatigue and creep damage for each selected assessment point includes: calculating and evaluating fatigue and creep damage for each selected assessment point using the Miner linear cumulative damage algorithm; specifically including: Calculate fatigue damage; Calculate creep damage based on the temperature and stress levels at the test points.

4. The method for compiling an acceleration mission test spectrum considering multiple modes and multiple hazard points according to claim 3, characterized in that: The calculation of fatigue damage includes: the calculated value of cumulative fatigue damage. In the formula n i For a certain stress level, the number of cycles, N i D is the number of cycles required to reach failure at this stress level. f This is the calculated value for cumulative fatigue damage.

5. The method for compiling an acceleration mission test spectrum considering multiple modes and multiple hazard points according to claim 3, characterized in that: The calculation of creep damage based on the temperature and stress levels at the assessment points includes: creep damage is calculated using... Calculate, where t i t is the holding time under a certain load level. ci D is the time required for creep rupture under this load level. c This is the calculated value for cumulative creep damage.

6. The method for compiling an acceleration mission test spectrum considering multiple modes and multiple hazard points according to claim 1, characterized in that: The process of selecting the assessment point with the maximum fatigue damage value and converting it into the number of slow-to-maximum-slow-speed cycles of the acceleration spectrum includes: comparing the fatigue damage value and creep damage value of each assessment point, and converting the assessment point with the maximum fatigue damage value into the number of slow-to-maximum-slow-speed cycles of the acceleration spectrum. In the formula D f The total fatigue damage in each cycle is represented by D, where D is the total fatigue damage in the formula. I-M-I The fatigue damage is for a single slow-maximum-slow cycle, where N is the calculated cycle number.

7. The method for compiling an acceleration mission test spectrum considering multiple modes and multiple hazard points according to claim 1, characterized in that: The calculation of the maximum state holding time from the assessment point with the maximum creep damage value includes: the maximum state holding time of the assessment point with the maximum creep damage value converted into the maximum state holding time of the acceleration spectrum. In the formula: D c D is the calculated value for cumulative creep damage. M This represents creep damage per unit time under maximum conditions.

8. The acceleration mission test spectrum compilation system considering multiple modes and multiple hazard points as described in any one of claims 1-7, characterized in that: include: The acquisition module is used to acquire the stress and temperature distribution of components under different loads and operating conditions; The selection module is used to select key performance indicators of multiple components during operation as potential hazards for analysis. The calculation and evaluation module is used to calculate and evaluate fatigue and creep damage for each selected assessment point. The statistical analysis module is used to statistically analyze the distribution characteristics of the speed change rate in the long-term life test spectrum and determine the switching rate from idle state to maximum state. The comparison module is used to compare the damage values ​​of different failure modes at each assessment point. The assessment point with the maximum fatigue damage is selected and converted into the number of slow-maximum-slow cycle times of the acceleration spectrum. The assessment point with the maximum creep damage is selected and converted into the maximum state holding time. The compilation module is used to compile the test spectrum of the acceleration task based on the number of slow-maximum-slow-speed cycles, the maximum state holding time, and the switching rate from slow state to maximum state. The testing module is used to verify the consistency of damage between the accelerated mission test spectrum and the long-term life test spectrum.

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