A method and system for determining stress for evaluating the fatigue damage of a roulette under a working process

Abstract

The present invention relates to the technical field of aeroengines, and discloses a stress determination method and system for evaluating the fatigue damage of a disk under a working process. By uniformly converting the stress at each time point of the disk assessment part into the stress at the temperature of the time point with the minimum fatigue life, the equivalent stress history of the disk assessment part is determined, and the peak-valley stress values of the 1st, 3rd, and 4th type stress cycles of the disk assessment part under the working process are obtained by using the rain-flow counting method. The present invention can reasonably determine the stress for evaluating the fatigue damage of the disk under the working process, provide support for accurately identifying the maximum fatigue damage of the disk under the working process, avoid the problem in the prior art that for a disk with a large difference in the variation laws of the material tensile strength and fatigue performance with temperature, the maximum fatigue damage of the disk cannot be effectively identified, resulting in unreasonable determination of the fatigue life damage of the disk, thereby reducing the risk of premature fatigue failure of the disk during its service life.

Description

Technical Field

[0001] The present invention relates to the technical field of aeroengines, and discloses a method and system for determining stress for evaluating fatigue damage of a disk under a working history. Background Art

[0002] The stress and temperature at the assessment part of the aeroengine disk change with time under the working history. Since the temperature corresponding to the stress at the assessment part varies at each time point, in order to facilitate the analysis of the fatigue life damage of the disk, it is necessary to uniformly convert the stress history of the disk assessment part into the stress history at a certain specific temperature.

[0003] The current stress conversion principle is determined according to the tensile strength of the material at the temperature corresponding to each stress point and the tensile strength of the material at a specific temperature. However, the current stress conversion method is applicable to analyzing the fatigue life damage of disks with the same variation law of material tensile strength and fatigue performance with temperature. But for disks with a large difference in the variation law of material tensile strength and fatigue performance with temperature, the maximum fatigue damage of the disk cannot be effectively identified, resulting in unreasonable determination of the fatigue life damage of the disk, and there is a risk of premature fatigue failure of the disk during its life cycle, posing a certain hidden danger to the safe operation of the engine. Summary of the Invention

[0004] The purpose of the present invention is to provide a method and system for determining stress for evaluating fatigue damage of a disk under a working history, which can reasonably determine the stress for evaluating fatigue damage of the disk under the working history, provide support for accurately identifying the maximum fatigue damage of the disk under the working history, and thus reduce the risk of premature fatigue failure of the disk during its life cycle.

[0005] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0006] A method for determining stress for evaluating fatigue damage of a disk under a working history, comprising:

[0007] Carrying out finite element strength analysis of the disk under a typical working history, and extracting the stress at each time point and the corresponding temperature of the assessment part of the disk, where the assessment part includes but is not limited to the disk center, disk hole edge, and fillet part of the disk;

[0008] According to the temperature at each time point of the disk, combining with the fatigue performance curve of the disk material at a typical temperature in the material handbook, and obtaining the fatigue performance curve of the disk at the corresponding temperature by interpolation, where the fatigue performance curve is a stress-life curve or a strain-life curve;

[0009] At every moment of the roulette wheel Under the pulsating cycle with stress ratio of 0, combined with temperature The fatigue performance curve under the pulsation cycle is calculated as Fatigue life , and extract fatigue life Minimum Corresponding temperature ;

[0010] Fatigue life of the wheel test parts Less than 10 7 The time point , using temperature The fatigue performance curve under the condition of Fatigue life under The corresponding stress According to stress Fatigue life obtained by analysis Less than 10 7 The equivalent stress at each time point ;

[0011] Fatigue life of the wheel test parts Not less than 10 7 The time point , according to each time point Stress , the wheel material at the corresponding temperature Fatigue strength under And the disc material at temperature Fatigue strength under , analyze and obtain fatigue life Not less than 10 7 Second time point Equivalent stress ;

[0012] According to fatigue life Not less than 10 7 Second time point Equivalent stress and fatigue life Less than 10 7 The equivalent stress at each time point The rain flow counting method is used to obtain the peak and valley stresses of types 1, 3, and 4 stress cycles at the wheel test site under the working history.

[0013] Further analysis yields the fatigue life Less than 10 7 The equivalent stress at each time point The methods include:

[0014] According to the roulette assessment position at each time point Stress Obtaining the absolute value of stress , and the stress symbol is obtained according to the stress magnitude analysis ,in Pick , Pick , Pick ;

[0015] According to the stress solution Combined stress symbols according to Calculate fatigue life Less than 10 7 Equivalent stress at the next moment .

[0016] Further, according to Get fatigue life Not less than 10 7 Equivalent stress at the next moment .

[0017] Furthermore, the temperature Fatigue strength under and temperature Fatigue strength under The corresponding stress concentration factor is 1, the stress ratio is 0, and the number of cycles is 10 in the life curve of the wheel material manual. 7 The next stress value.

[0018] To achieve the above technical effects, the present invention further provides a stress determination system for evaluating wheel disk fatigue damage under a working history, which is used to implement the stress determination method for evaluating wheel disk fatigue damage under a working history, comprising:

[0019] The finite element analysis module is used to extract the strength of the wheel at each time point by conducting finite element strength analysis of the wheel under typical working process. Stress and corresponding temperature The test parts include but are not limited to the center of the wheel, the edge of the wheel hole, and the rounded part;

[0020] Fatigue curve acquisition module, used to obtain the fatigue curve at each moment of the wheel Temperature Combined with the fatigue performance curve of the wheel material at typical temperature in the material manual, the wheel at the corresponding temperature is obtained by interpolation. The fatigue performance curve is a stress-life curve or a strain-life curve;

[0021] The first analysis module is used to analyze the roulette wheel at each time point Under the pulsating cycle with stress ratio of 0, combined with temperature The fatigue performance curve under the pulsation cycle is calculated as Fatigue life , and extract fatigue life Minimum Corresponding temperature ;

[0022] The second analysis module is used to extract the fatigue life of the wheel test parts Less than 10 7 The time point , and use temperature The fatigue performance curve under the condition of Fatigue life under The corresponding stress According to stress Fatigue life obtained by analysis Less than 10 7 The equivalent stress at each time point ;

[0023] The third analysis module is used to extract the fatigue life of the wheel test parts Not less than 10 7 The time point , and according to each time point Stress , the wheel material at the corresponding temperature Fatigue strength under And the disc material at temperature Fatigue strength under , analyze and obtain fatigue life Not less than 10 7 Second time point Equivalent stress ;

[0024] Stress determination module for fatigue life Not less than 10 7 Second time point Equivalent stress and fatigue life Less than 10 7 The equivalent stress at each time point The rain flow counting method is used to obtain the peak and valley stresses of types 1, 3, and 4 stress cycles at the wheel test site under the working history.

[0025] Further, in the second analysis module, according to the roulette inspection part at each time point stress calculate the absolute value of the stress , and analyze the stress symbol according to the stress magnitude , where take , take , take ;

[0026] According to the solved stress combined with the stress symbol in accordance with calculate the fatigue life less than 10 7 equivalent stress at the time point of cycles .

[0027] Further, the third analysis module according to obtain the fatigue life not less than 10 7 equivalent stress at the time point of cycles .

[0028] Further, in the third analysis module, the fatigue strength at temperature and the fatigue strength at temperature are both the stress values corresponding to a stress concentration factor of 1, a stress ratio of 0, and a number of cycles of 10 in the life curve of the roulette material handbook cycles. 7 times.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention can realize the reasonable determination of the stress for fatigue damage assessment under the working process of the roulette, provide support for accurately identifying the maximum fatigue damage under the working process of the roulette, and avoid the problem in the prior art that for a roulette with a large difference in the variation laws of material tensile strength and fatigue performance with temperature, the maximum fatigue damage of the roulette cannot be effectively identified, resulting in unreasonable determination of the fatigue life damage of the roulette, thereby reducing the risk of premature fatigue failure of the roulette during its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flowchart of the method for determining the stress for fatigue damage assessment of the roulette under the working process in Embodiment 1 or 2;

[0031] Figure 2 is a structural block diagram of the system for determining the stress for fatigue damage assessment of the roulette under the working process in the embodiment;

[0032] Among them, 1. Finite element analysis module; 2. Fatigue curve acquisition module; 3. First analysis module; 4. Second analysis module; 5. Third analysis module; 6. Stress determination module. Specific implementation mode

[0033] The present invention will be further described in detail below in conjunction with embodiments and the accompanying drawings. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments. All technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0034] Embodiment 1

[0035] See Figure 1 and Figure 2 , a stress determination method for evaluating the fatigue damage of a disk under a working process, including:

[0036] Carry out finite element strength analysis of the disk under a typical working process, and extract the stress and the corresponding temperature at each time point of the disk's assessment part, and the assessment part includes but is not limited to the disk center, disk hole edge, and fillet part of the disk;

[0037] According to the temperature at each time point of the disk, combined with the fatigue performance curve of the disk material at a typical temperature in the material manual, interpolate to obtain the fatigue performance curve of the disk at the corresponding temperature , and the fatigue performance curve is a stress-life curve or a strain-life curve;

[0038] For the pulsating cycle with a stress ratio of 0 at each time point of the disk, combined with the fatigue performance curve at the temperature , calculate the fatigue life when the peak stress of the pulsating cycle is , and extract the minimum value of the fatigue life and the corresponding temperature ;

[0039] For the time points where the fatigue life 7 of the disk's assessment part is less than 10 , use the fatigue performance curve at the temperature to analyze and obtain the stress corresponding to the fatigue life at each time point ; Analyze and obtain the fatigue life according to the stress Less than 10 7 The equivalent stress at each time point ;

[0040] Fatigue life of the wheel test parts Not less than 10 7 The time point , according to each time point Stress , the wheel material at the corresponding temperature Fatigue strength under And the disc material at temperature Fatigue strength under , analyze and obtain fatigue life Not less than 10 7 Second time point Equivalent stress ;

[0041] According to fatigue life Not less than 10 7 Second time point Equivalent stress and fatigue life Less than 10 7 The equivalent stress at each time point The rain flow counting method is used to obtain the peak and valley stresses of types 1, 3, and 4 stress cycles at the wheel test site under the working history.

[0042] In this embodiment, by comprehensively considering the stress variations in the wheel disc over its operating history, the stress at each time point in the wheel disc's assessment area is uniformly converted to the stress at the temperature at the time point with minimum fatigue life (i.e., maximum fatigue damage). This determines the equivalent stress history of the wheel disc's assessment area, and employs the rainflow counting method to obtain the peak-to-valley stresses for Class 1, 3, and 4 stress cycles at the assessment area over the operating history. This method of this embodiment enables the rational determination of stresses for fatigue damage assessment over the wheel disc's operating history, as well as the rational determination of Class 1, 3, and 4 stress cycles for the wheel disc, effectively capturing the wheel disc's fatigue damage. This method overcomes the prior art issue of being unable to effectively identify the maximum fatigue damage of a wheel disc whose material exhibits significant differences in temperature-dependent variations in tensile strength and fatigue properties, leading to inappropriate determination of fatigue life damage. This reduces the risk of premature fatigue failure within the wheel disc's lifespan and provides support for wheel disc life management.

[0043] Based on the same inventive concept, this embodiment further provides a stress determination system for evaluating wheel disk fatigue damage under a working history, which is used to implement the stress determination method for evaluating wheel disk fatigue damage under a working history, comprising:

[0044] Finite element analysis module 1 is used to extract the strength of the wheel at each time point by conducting finite element strength analysis of the wheel under typical working process. Stress and corresponding temperature The test parts include but are not limited to the center of the wheel, the edge of the wheel hole, and the rounded part;

[0045] Fatigue curve acquisition module 2 is used to obtain the fatigue curve according to each moment of the wheel. Temperature Combined with the fatigue performance curve of the wheel material at typical temperature in the material manual, the wheel at the corresponding temperature is obtained by interpolation. The fatigue performance curve is a stress-life curve or a strain-life curve;

[0046] The first analysis module 3 is used to analyze the roulette wheel at each time point Under the pulsating cycle with stress ratio of 0, combined with temperature The fatigue performance curve under the pulsation cycle is calculated as Fatigue life , and extract fatigue life Minimum Corresponding temperature ;

[0047] The second analysis module 4 is used to extract the fatigue life of the wheel test part Less than 10 7 The time point , and use temperature The fatigue performance curve under the condition of Fatigue life under The corresponding stress According to stress Fatigue life obtained by analysis Less than 10 7 The equivalent stress at each time point ;

[0048] The third analysis module 5 is used to extract the fatigue life of the wheel test part Not less than 10 7 The time point , and according to each time point Stress , the wheel material at the corresponding temperature Fatigue strength under And the disc material at temperature Fatigue strength under , analyze and obtain fatigue life Not less than 107 The equivalent stress at the next time point ; ;

[0049] A stress determination module 6, configured to obtain, according to the fatigue life not less than 10 7 times of the next time point equivalent stress and the fatigue life less than 10 7 equivalent stress at each time point less than 10 times , and obtain the peak-valley stress of the stress cycles of categories 1, 3, and 4 at the evaluation part of the disk under the working process by using the rain-flow counting method.

[0050] Embodiment 2

[0051] See Figure 1 , a stress determination method for evaluating the fatigue damage of a disk under a working process, including:

[0052] Step 1: Conduct a finite element strength analysis of the disk under a typical working process, and extract the stress and the corresponding temperature at each time point of the evaluation part of the disk, where the evaluation part includes but is not limited to the disk center, the disk hole edge, and the fillet part of the disk;

[0053] Step 2: According to the temperature at each time point of the disk and in combination with the fatigue performance curve of the disk material at a typical temperature in the material handbook, obtain the fatigue performance curve of the disk at the corresponding temperature by interpolation, where the fatigue performance curve is a stress-life curve or a strain-life curve;

[0054] Step 3: For the pulsating cycle with a stress ratio of 0 at each time point of the disk, and in combination with the fatigue performance curve at the corresponding temperature calculate the fatigue life when the peak stress of the pulsating cycle is , and extract the temperature corresponding to the minimum value of the fatigue life;

[0055] Step 4: For the fatigue life less than 10 7 times of the time points at the evaluation part of the disk , use the fatigue performance curve at the corresponding temperature to analyze and obtain the fatigue life at each time point and the corresponding stress ; According to the stress analysis, the fatigue life less than 10 7 equivalent stress at each time point ;

[0056] In this embodiment, according to the stress at each time point of the disk assessment part , the absolute value of the stress is obtained , and the stress sign is analyzed according to the stress magnitude where take [[ID= Twenty-six]] take , take ;

[0057] According to the solved stress combined with the stress sign in accordance with calculate the fatigue life less than 10 7 equivalent stress at the time point of times .

[0058] Step Five. For the fatigue life not less than 10 7 times at the time point , according to the stress at each time point , the fatigue strength of the disk material at the corresponding temperature and the fatigue strength of the disk material at the temperature , analyze and obtain the fatigue life not less than 10 7 equivalent stress at the time point of times ;

[0059] In this embodiment, according to obtain the fatigue life not less than 10 7 equivalent stress at the time point of times . Among them, the fatigue strength at the temperature and the fatigue strength at the temperature are both the stress values corresponding to the stress concentration factor of 1, the stress ratio of 0, and the number of cycles of 10 7 times in the life curve of the disk material manual.

[0060] ​Step 6. According to the fatigue life not less than 10 7 times of time points equivalent stress and fatigue life less than 10 7 equivalent stress of each time point of times , the peak-valley stress of the 1st, 3rd, and 4th type stress cycles at the assessment part of the disk under the working process is obtained by using the rain flow counting method.

[0061] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for determining stress used in evaluating the fatigue damage of a roulette under a working process, characterized in that, Comprising: Conduct finite element strength analysis of the wheel disc under typical working processes, and extract the stress and the corresponding temperature at each time point of the inspected part of the wheel disc. The inspected part includes, but is not limited to, the center of the wheel disc, the edge of the wheel disc hole, and the rounded part. ​ According to the temperature at each moment of the roulette wheel and combining with the fatigue performance curve of the roulette wheel material at typical temperatures in the material handbook, the fatigue performance curve of the roulette wheel at the corresponding temperature is obtained by interpolation. The fatigue performance curve is a stress-life curve or a strain-life curve; For the wheel at each moment point Under the pulsating cycle with a stress ratio of 0, combined with the temperature Under the fatigue performance curve, calculate the peak stress of the pulsating cycle to be The fatigue life of And extract the fatigue life Minimum value The corresponding temperature ; For the fatigue life of the roulette assessment part Less than 10 7 At the time point , the fatigue performance curve at the temperature is used to analyze the fatigue life at each time point ; The corresponding stress is obtained; according to the stress , the equivalent stress less than 10 7 times at each time point is obtained ; For the fatigue life of the roulette assessment part Not less than 10 7 At the time point of , according to each time point Of stress , the fatigue strength of the roulette material at the corresponding temperature And the fatigue strength of the roulette material at temperature Analyze to obtain the fatigue life Not less than 10 At the time point of Of equivalent stress 7 At the time point of ;​ According to the fatigue life not less than 10 7 times of time points equivalent stress and fatigue life less than 10 7 equivalent stress at each time point less than 10 times , the peak-valley stress of the 1st, 3rd, and 4th type stress cycles at the assessment part of the disk under the working process is obtained by using the rain-flow counting method.

2. The stress determination method for the fatigue damage assessment of the lower wheel disc under the working process according to claim 1, wherein Analysis to obtain the fatigue life Less than 10 7 The equivalent stress at each time point The method includes: According to the stress of the roulette assessment part at each time point stress Calculate the absolute value of the stress and analyze the stress symbol according to the stress magnitude where take , take , take ; According to the solved stress Combined with the stress symbol According to The fatigue life is calculated Less than 10 7 The equivalent stress at the time point .

3. The method for determining stress for evaluating fatigue damage of the lower roulette wheel in the working process according to claim 1, characterized in that, According to obtain the fatigue life not less than 10 7 equivalent stress at the time point .

4. The method for determining stress for evaluating the fatigue damage of the lower wheel disc under the working process according to claim 3, characterized in that Temperature Fatigue strength under and temperature Fatigue strength under are both the stress values corresponding to a stress concentration factor of 1, a stress ratio of 0, and a number of cycles of 10 7 times in the life curve of the disk material handbook.

5. A stress determination system for evaluating the fatigue damage of a roulette wheel under a working process, which is used to implement the stress determination method for evaluating the fatigue damage of a roulette wheel under a working process according to any one of claims 1-4, and is characterized in that, Including: The finite element analysis module is used to perform finite element strength analysis on the roulette wheel under typical working conditions, and extract the stress and corresponding temperature at each time point of the evaluation part of the roulette wheel. The evaluation part includes but is not limited to the center of the roulette wheel, the edge of the roulette wheel hole, and the rounded part; ​ A fatigue curve acquisition module, which is used to obtain, according to the temperature of each moment point of the wheel disc and in combination with the fatigue performance curve of the wheel disc material in the material handbook at typical temperatures, obtain the fatigue performance curve of the wheel disc at the corresponding temperature by interpolation. The fatigue performance curve is a stress-life curve or a strain-life curve; ​ The first analysis module is used to calculate, according to the pulsating cycle with a stress ratio of 0 at each time point of the roulette wheel, in combination with the fatigue performance curve at a certain temperature, the fatigue life with the peak stress of the pulsating cycle being and extract the minimum value of the fatigue life , and extract the temperature corresponding to the minimum value ; ​ A second analysis module, configured to extract the fatigue life of the roulette assessment part less than 10 7 times of the time point , and adopt the fatigue performance curve at the temperature to analyze and obtain the fatigue life at each time point and the corresponding stress at the fatigue life ; According to the stress The fatigue life is obtained through analysis Less than 10 7 The equivalent stress at each time point ; The third analysis module is used to extract the fatigue life of the roulette assessment part not less than 10 7 times of time points , and according to each time point of stress , the fatigue strength of the roulette material at the corresponding temperature , and the fatigue strength of the roulette material at temperature , analyze and obtain the fatigue life not less than 10 times of time points not less than 10 7 times of time points equivalent stress ; A stress determination module, which is used to determine, according to the fatigue life not less than 10 7 times of moment points equivalent stress and fatigue life less than 10 7 equivalent stress of each moment point of times , and the peak-valley stresses of the stress cycles of Categories 1, 3, and 4 at the assessment part of the disk under the working process are obtained by using the rain-flow counting method.

6. The stress determination system for evaluating the fatigue damage of the lower wheel of the working process according to claim 5, characterized in that In the second analysis module, according to the stress of the roulette assessment part at each time point stress calculate the absolute value of the stress and analyze the stress sign according to the stress magnitude where take , take , take ; According to the solved stress Combined with the stress symbol In accordance with The fatigue life is calculated Less than 10 7 The equivalent stress at the time point .

7. The stress determination system for evaluating the fatigue damage of the lower wheel disc under the working process according to claim 5, characterized in that, The third analysis module, based on obtains the fatigue life not less than 10 7 equivalent stress at the time point .

8. The stress determination system for evaluating the fatigue damage of the lower wheel of the working process according to claim 7, characterized in that In the third analysis module, the fatigue strength at the temperature and the fatigue strength at the temperature are both the stress values corresponding to a stress concentration factor of 1, a stress ratio of 0, and a number of cycles of 10 in the life curve of the disk material handbook, and a number of cycles of 10 times. 7 ​

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