Stress determination method and system for wheel disc fatigue damage evaluation in working process

Abstract

The invention relates to the technical field of aero-engines, and discloses a stress determination method and system for wheel disc fatigue damage evaluation in a working process, and the method comprises the steps: uniformly converting the stress of a wheel disc examination part at each time point into the stress at the temperature of the time point with the minimum fatigue life, thereby determining the equivalent stress process of the wheel disc examination part, and determining the fatigue damage of the wheel disc. And a rain flow counting method is adopted to obtain the peak-valley value stress of the first, third and fourth types of stress cycles of the wheel disc examination part in the working process. According to the method, the stress for fatigue damage evaluation in the working process of the wheel disc can be reasonably determined, and support is provided for accurate identification of the maximum fatigue damage in the working process of the wheel disc; the problem that the determined fatigue life damage of the wheel disc is unreasonable due to the fact that the maximum fatigue damage of the wheel disc with the material tensile strength and fatigue performance greatly different along with the temperature change rule cannot be effectively recognized in the prior art is solved, and the risk of fatigue failure of the wheel disc in advance in the life period is reduced.

Description

Technical Field

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

[0002] The stress and temperature at the assessment part of the aeroengine disk change with time under the working process. Since the temperature corresponding to the stress at the assessment part is different 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 at the assessment part of the disk 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 a system for determining stress for evaluating fatigue damage of a disk under a working process, which can reasonably determine the stress for evaluating 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, 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: A method for determining stress for evaluating fatigue damage of a disk under a working process, comprising: Carrying out finite element strength analysis of the disk under a typical working process, and extracting the stress at each time point of the assessment part of the disk and the corresponding temperature, where the assessment part includes but is not limited to the disk center, the disk hole edge, and the fillet part of the disk; 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 manual, 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; For the disk at each time point under a pulsating cycle with a stress ratio of 0, combining with the temperature The fatigue performance curve under the condition of pulsation cycle is calculated as Fatigue life , and extract the fatigue life Minimum Corresponding temperature ; 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 analysis Less than 10 7 The equivalent stress at each time point ; 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 The equivalent stress ; According to fatigue life Not less than 10 7 Second time point The 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 1, 3, and 4 stress cycles at the wheel test site under the working history.

[0006] Further, the fatigue life is analyzed Less than 10 7 The equivalent stress at each time point The methods include: According to the roulette test position at each time point Stress Find the absolute value of stress , and analyze the stress symbols based on the stress magnitudes , where Take , Take , Take ; According to the solved stress Combined with the stress symbol According to Calculate the fatigue life Less than 10 7 The equivalent stress at the time point of cycles .

[0007] Furthermore, according to Obtain the fatigue life Not less than 10 7 The equivalent stress at the time point of cycles .

[0008] Furthermore, the fatigue strength at temperature And the fatigue strength at temperature And The fatigue strength at temperature Are all the stress values corresponding to a stress concentration factor of 1, a stress ratio of 0, and a number of cycles of 10 7 cycles in the life curve of the disk material handbook.

[0009] To achieve the above technical effects, the present invention also provides a stress determination system for evaluating the fatigue damage of a disk under a working process, which is used to implement the stress determination method for evaluating the fatigue damage of a disk under the working process, including: A finite element analysis module, which is used to extract the stress And the corresponding temperature At each time point Of the disk by conducting a finite element strength analysis of the disk under a typical working process, and the inspected parts include but are not limited to the disk center, the disk hole edge, and the fillet part of the disk; A fatigue curve acquisition module, which is used to interpolate to obtain the fatigue performance curve of the disk at the corresponding temperature According to the temperature At each time point of the disk and the fatigue performance curve of the disk material in the material handbook at a typical temperature, and the fatigue performance curve is a stress-life curve or a strain-life curve; A first analysis module, which is used to calculate the peak stress of the pulsating cycle as According to 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 ​Fatigue life and extract the fatigue life Minimum value The corresponding temperature ; The second analysis module is used to extract the fatigue life of the disc assessment part Less than 10 7 The time points of the number of times and use the fatigue performance curve at the temperature to analyze and obtain the fatigue life at each time point The corresponding stress ; According to the stress Analyze and obtain the fatigue life Less than 10 The equivalent stress at each time point of the number of times 7 ; ; The third analysis module is used to extract the fatigue life of the disc assessment part Not less than 10 7 The time points of the number of times and according to each time point The stress , the fatigue strength of the disc material at the corresponding temperature and the fatigue strength of the disc material at the temperature to analyze and obtain the fatigue life Not less than 10 The equivalent stress at the time point of the number of times ; 7 The equivalent stress at the time point of the number of times ; ; The stress determination module is used to determine the fatigue life Not less than 10 7 The time points of the number of times The equivalent stress and the fatigue life Less than 10 7 The equivalent stress at each time point of the number of times , and the peak and valley stress values of the 1, 3, and 4 types of stress cycles at the disc assessment part under the working process are obtained by using the rain flow counting method.

[0010] Furthermore, in the second analysis module, according to the stress of the disc assessment part at each time point Take the absolute value of the stress and analyze and obtain 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 Calculate the fatigue life Less than 10 7 Equivalent stress at the time point of cycles .

[0011] Furthermore, the third analysis module is based on Obtain the fatigue life Not less than 10 7 Equivalent stress at the time point of cycles .

[0012] Furthermore, 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 7 cycles in the life curve of the disk material handbook.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention can reasonably determine the stress for evaluating the fatigue damage of the disk during its working process, provide support for accurately identifying the maximum fatigue damage of the disk during its working process, and avoid the problem in the prior art that for disks with large differences in the variation laws 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. Therefore, the risk of premature fatigue failure of the disk during its life cycle is reduced. Description of the Drawings

[0014] Figure 1 It is a flowchart of the method for determining the stress for evaluating the fatigue damage of the disk during the working process in Embodiment 1 or 2; Figure 2 It is a structural block diagram of the system for determining the stress for evaluating the fatigue damage of the disk during the working process in the embodiment; 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. Detailed Embodiments

[0015] The present invention will be further described in detail below in conjunction with the embodiments and the 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.

[0016] Embodiment 1 See Figure 1 and Figure 2 , a stress determination method for evaluating the fatigue damage of a roulette wheel under a working process, including: Conduct a finite element strength analysis of the roulette wheel under a typical working process, and extract the stress at each time point and the corresponding temperature of the roulette wheel's assessment location, where the assessment location includes but is not limited to the center of the roulette wheel, the edge of the roulette wheel hole, and the rounded part; According to the temperature at each time point of the roulette wheel, combined with the fatigue performance curve of the roulette wheel material at a typical temperature in the material handbook, interpolate to obtain the fatigue performance curve of the roulette wheel at the corresponding temperature , and the fatigue performance curve is a stress-life curve or a strain-life curve; For the roulette wheel at each time point under a pulsating cycle with a stress ratio of 0, 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 ; For the time points where the fatigue life 7 of the roulette wheel's assessment location is less than 10 times, 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 equivalent stress of each time point where the fatigue life is less than 10 7 times according to the stress ; For the time points where the fatigue life 7 of the roulette wheel's assessment location is not less than 10 times, according to the stress at each time point , the fatigue strength of the roulette wheel material at the corresponding temperature and the fatigue strength of the roulette wheel material at the temperature , analyze and obtain the equivalent stress of the time points 7 where the fatigue life is not less than 10 ; 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 of times , the peak-valley stress of the 1st, 3rd, and 4th type stress cycles of the disc assessment part under the working process is obtained by using the rain flow counting method.

[0017] In this embodiment, by comprehensively considering the stress change of the disc under the working process, the stress at each time point of the disc assessment part is uniformly converted into the stress at the temperature of the time point with the minimum fatigue life (that is, the maximum fatigue damage), so as to determine the equivalent stress history of the disc assessment part, and the peak-valley stress of the 1st, 3rd, and 4th type stress cycles of the disc assessment part under the working process is obtained by using the rain flow counting method. The method of this embodiment can realize the reasonable determination of the stress for fatigue damage assessment of the disc under the working process, reasonably determine the 1st, 3rd, and 4th type stress cycles of the disc, effectively obtain the fatigue damage of the disc, and can avoid the problem that the maximum fatigue damage of the disc cannot be effectively identified in the prior art for discs with large differences in the variation laws of material tensile strength and fatigue performance with temperature, resulting in unreasonable determination of the disc fatigue life damage, thereby reducing the risk of premature fatigue failure of the disc during the life cycle and providing support for the disc life management.

[0018] Based on the same inventive concept, this embodiment also provides a system for determining the stress for fatigue damage assessment of a disc under a working process, which is used to implement the method for determining the stress for fatigue damage assessment of a disc under a working process, including: Finite element analysis module 1, which is used to extract the stress and the corresponding temperature at each time point of the disc assessment part by carrying out finite element strength analysis of the disc under a typical working process, , and the assessment part includes but is not limited to the disc center, disc hole edge, and fillet part of the disc; Fatigue curve acquisition module 2, which is used to obtain the fatigue performance curve of the disc at the corresponding temperature by interpolating according to the temperature at each time point of the disc and combining the fatigue performance curve of the disc material at a typical temperature in the material manual, and the fatigue performance curve is a stress-life curve or a strain-life curve; First analysis module 3, which is used to combine the temperature at each time point of the disc according to the pulsating cycle with a stress ratio of 0, Under the fatigue performance curve, calculate the peak stress of the pulsating cycle as The fatigue life of , and extract the fatigue life Minimum value The corresponding temperature ; The second analysis module 4 is used to extract the fatigue life of the disc assessment part Less than 10 7 The time points of , and use the fatigue performance curve at temperature To analyze and obtain the fatigue life at each time point The corresponding stress ; According to the stress Analyze and obtain the fatigue life Less than 10 The equivalent stress at each time point of 7 ; ; The third analysis module 5 is used to extract the fatigue life of the disc assessment part Not less than 10 7 The time points of , and according to each time point The stress of , the fatigue strength of the disc material at the corresponding temperature And the fatigue strength of the disc material at temperature As well as the fatigue strength of the disc material at temperature To analyze and obtain the fatigue life Not less than 10 The equivalent stress at the time point of 7 ; ; ; The stress determination module 6 is used to determine the fatigue life according to Not less than 10 7 The time points of The equivalent stress of And the fatigue life Less than 10 7 The equivalent stress at each time point of , and use the rain flow counting method to obtain the peak and valley stresses of the 1st, 3rd, and 4th type stress cycles at the disc assessment part under the working process.

[0019] Example 2 Refer to Figure 1 , A stress determination method for fatigue damage assessment of a disc under a working process, including: Step 1. Conduct a finite element strength analysis of the disc under a typical working process, and extract the stress at each time point of the disc assessment part ; and the corresponding temperature , the inspected parts include but are not limited to the center of the disk, the edge of the disk hole, and the rounded part; Step 2. According to the temperature of the disk at each moment Combined with the fatigue performance curve of the disk material at typical temperatures in the material manual, the fatigue performance curve of the disk at the corresponding temperature is obtained by interpolation , and the fatigue performance curve is a stress-life curve or a strain-life curve; Step 3. For the disk at each moment Under the pulsating cycle with a stress ratio of 0, combined with the fatigue performance curve at the temperature , calculate the fatigue life of the pulsating cycle peak stress To be , and extract the minimum value of the fatigue life The corresponding temperature Minimum value ; ; Step 4. For the fatigue life of the inspected parts of the disk Less than 10 7 Times of the moment , use the fatigue performance curve at the temperature Analyze and obtain the fatigue life at each moment The corresponding stress ; According to the stress Analyze and obtain the equivalent stress of each moment with a fatigue life Less than 10 Times; 7 ; ; In this embodiment, according to the stress of the inspected parts of the disk at each moment Obtain the absolute value of the stress , and analyze and obtain the stress sign according to the stress magnitude , where Take To be , Take , Take ; According to the solved stress Combined with the stress sign According to Calculate and obtain the equivalent stress of the moment with a fatigue life Less than 10 7 Times .

[0020] Step 5. For the fatigue life of the inspected parts of the disk Not less than 107 The moment of the nth time , according to each moment of stress , the fatigue strength of the disk material at the corresponding temperature and the fatigue strength of the disk material at the temperature are analyzed to obtain the fatigue life not less than 10 times the equivalent stress at the moment of the nth time 7 ; In this embodiment, according to the fatigue life is obtained not less than 10 times the equivalent stress at the moment 7 . Among them, 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 cycle number of 10 times in the life curve of the disk material handbook 7 .

[0021] Step Six: According to the fatigue life not less than 10 7 times the equivalent stress at the moment of the nth time and the fatigue life less than 10 7 times the equivalent stress at each moment , the peak-valley stress of the 1st, 3rd, and 4th type stress cycles at the evaluation part of the disk under the working process is obtained by using the rain flow counting method

[0022] The above is only a preferred embodiment of the present invention and is 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 in the protection scope of the present invention

Claims

1. A method for determining stress used in the fatigue damage assessment of a roulette under a working process, characterized in that including: Conduct a finite element strength analysis of the wheel disc under typical working conditions, and extract the stress at each time point and the corresponding temperature of the assessment parts of the wheel disc. The assessment parts include but are 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 manual, 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 roulette wheel at each moment point Under a 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 , 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 and obtain the fatigue life at each time point ; According to the stress corresponding to the fatigue life ; Based on the stress , the equivalent stress of each time point with a fatigue life less than 10 7 times is obtained ; 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 The equivalent stress ; According to the fatigue life not less than 10 7 times of moment equivalent stress and fatigue life less than 10 7 equivalent stress at each moment less than 10 times , the peak-valley stresses of the 1st, 3rd, and 4th type stress cycles at the assessment part of the disk under the working process are obtained by using the rainflow counting method.

2. The method for determining stress for evaluating fatigue damage of the lower wheel disc under the working process according to claim 1, wherein Analysis to obtain fatigue life Less than 10 7 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 wheel disc under 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 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 Both are 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, characterized in that, including: A finite element analysis module, which is used to perform finite element strength analysis on the roulette wheel under typical working conditions and extract the stress and the corresponding temperature at each time point of the assessment part of the roulette wheel, where the assessment part includes but is not limited to the center of the roulette wheel, the edge of the roulette wheel hole, and the fillet part; ​ A fatigue curve acquisition module, which is used to obtain the fatigue performance curve of the disk at the corresponding temperature by interpolation according to the temperature of each time point of the disk and combining the fatigue performance curves of the disk material in the material handbook at typical temperatures. 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 when the peak stress of the pulsating cycle is and extract the minimum value of the fatigue life , and extract the temperature corresponding to the minimum value ; ; The second analysis module is used to extract the fatigue life of the roulette assessment part Less than 10 7 The time points of , and use the fatigue performance curve at to analyze and obtain the fatigue life at each time point ; The corresponding stress ; According to the stress the fatigue life is obtained by analysis less than 10 7 the equivalent stress at each time point ; A third analysis module, configured to extract the fatigue life of the roulette assessment part not less than 10 7 times of time points , and based on 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 of 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 the equivalent stress and the fatigue life less than 10 7 times of the equivalent stress at each moment point , 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 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 .

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 of cycles .

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 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 7 times in the life curve of the disk material handbook.

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