Aero-engine cold end disc life evaluation spectrum compilation method and system

Abstract

The invention provides an aero-engine cold end disc life evaluation spectrum compilation method and system. The method comprises the steps that the rotating speed of each typical mission profile of an aero-engine is converted into stress; determining a stress average amplitude cyclic matrix of all typical mission profiles; dividing cyclic load types in the stress average amplitude cyclic matrixes of all typical mission profiles into main waves and secondary waves; compiling the main wave into a zero-maximum-zero program block, and carrying out uniform amplitude interval division and variable mean statistics on the secondary wave to form a secondary wave program block parameter table so as to compile a multi-level program block; and arranging all the program blocks according to a low-high-low sequence to obtain a low-cycle fatigue program block spectrum as an aero-engine cold end disc life evaluation spectrum. The contribution of different cycles to fatigue damage is accurately quantified, it is ensured that damage accumulation calculation is closer to real load distribution, and the accuracy of cold end disc life evaluation is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft engine life damage analysis, and in particular relates to a method and system for compiling an aircraft engine cold end disk life assessment spectrum. Background Art

[0002] According to general aviation engine specifications, cold-end disks (such as fan impellers and compressor disks) are critical components that limit the life of an aircraft engine and must undergo life assessment prior to assembly. The key to life assessment for cold-end disks is developing a life assessment spectrum that reflects the load characteristics of actual field service. Developing an accurate and easily testable life assessment spectrum is crucial for determining and extending the life of cold-end disks.

[0003] The primary failure mode of aircraft engine cold-end disks is low-cycle fatigue. Therefore, the compilation of life assessment spectra primarily considers the load characteristics of low-cycle fatigue damage. This typically involves selecting a typical mission profile, counting rainflows, removing small loads, and extracting three cycles: zero-maximum-zero, idle-maximum-idle, and cruise-maximum-cruise. This is then used to compile a three-cycle load spectrum.

[0004] However, the traditional three-cycle load spectrum compilation method has certain limitations:

[0005] 1. The cycle types only include three types of cycles, and fail to consider the impact of more cycle types, which is not conducive to improving the accuracy of life assessment;

[0006] 2. Not all cycle peaks can reach the maximum state, so it is not reasonable to equate the cycle statistics results to three types of cycles;

[0007] 3. The three-cycle load spectrum is aimed at the entire aircraft engine. For aircraft engine components, the problem of easy test loading also needs to be solved.

[0008] The above problems lead to the lack of effectiveness of traditional life assessment methods, which brings uncertainty to the life assessment of aircraft engine cold end discs. Summary of the Invention

[0009] The present invention provides a method and system for compiling a life assessment spectrum of an aircraft engine cold end disk, so as to solve the problem that the life assessment method of an aircraft engine cold end disk in the prior art lacks effectiveness.

[0010] In a first aspect, the present invention provides a method for compiling a life assessment spectrum for an aircraft engine cold end disk, comprising:

[0011] Obtain N typical mission profiles of aircraft engines;

[0012] Convert the rotational speed for each typical mission profile into stress;

[0013] The rain flow counting method is used to count the cycles of each stress and obtain the stress mean amplitude cycle matrix of each typical mission profile as the first stress mean amplitude cycle matrix;

[0014] Performing task mixing weighting on each first stress mean amplitude circulation matrix to obtain the stress mean amplitude circulation matrix of all typical task profiles as the second stress mean amplitude circulation matrix;

[0015] The cyclic load types in the second stress mean amplitude cyclic matrix are divided into primary waves and secondary waves. Among them, the stress cycle with a minimum value of zero and a maximum value close to the nominal stress at the critical point of the aircraft engine cold end disk at the maximum speed is classified as the primary wave, and the remaining stress cycles are all classified as secondary waves.

[0016] The primary wave is compiled into a zero-maximum-zero program block, and the secondary wave is divided into an average amplitude interval and variable mean value statistics are performed to form a secondary wave program block parameter table to compile an N-1 level program block;

[0017] All program blocks are arranged in the low-high-low order to obtain the low cycle fatigue program block spectrum, which is used as the life assessment spectrum of the aircraft engine cold end disk.

[0018] Optionally, the first aspect further includes:

[0019] The load is deleted from the second stress mean amplitude cyclic matrix according to the maximum amplitude and minimum value of all cycles in the load history to obtain the third stress mean amplitude cyclic matrix;

[0020] In the case of the existence of the third stress mean amplitude cyclic matrix, the cyclic load types in the third stress mean amplitude cyclic matrix are divided into primary waves and secondary waves.

[0021] Optionally, performing load deletion on the second stress mean amplitude circulatory matrix according to the maximum amplitude and minimum value of all cycles in the load history to obtain a third stress mean amplitude circulatory matrix includes:

[0022] The load deletion threshold Δ is calculated according to the following formula:

[0023] Δ=(G max -G min )·ω;

[0024] Among them, G max is the maximum amplitude of all cycles in the load history; G min is the minimum amplitude of all cycles in the load history; ω is a preset constant;

[0025] The loads smaller than the load deletion threshold in the second stress mean amplitude circulatory matrix are deleted to obtain a third stress mean amplitude circulatory matrix.

[0026] Optionally, converting the rotational speed of each typical mission profile into stress includes:

[0027] The nominal stress S at the dangerous point of the cold end disk of the aircraft engine at the target speed is calculated according to the following formula:

[0028]

[0029] Among them, S max is the nominal stress at the dangerous point of the cold end disk of the aircraft engine at the maximum speed; n is the speed of the cold end disk of the aircraft engine; n max It is the maximum speed of the cold end disk of the aircraft engine.

[0030] Optionally, performing task mixing weighting on each first stress mean amplitude circulatory matrix to obtain stress mean amplitude circulatory matrices of all typical task profiles as the second stress mean amplitude circulatory matrix includes:

[0031] Construct the expression of the second stress mean amplitude circulation matrix A:

[0032] A=∑(M i ×A i );

[0033] Among them, M i is the task mixing frequency of the typical task profile i; A i is the stress mean amplitude circulatory matrix of typical mission profile i.

[0034] Optionally, the main wave is compiled into a zero-maximum-zero program block and the secondary wave is divided into an average amplitude interval and variable mean value statistics are performed to form a secondary wave program block parameter table to compile an N-1 level program block, including:

[0035] The secondary wave is divided into mean amplitude intervals; wherein the mean is divided into N-1 intervals at equal intervals, and the amplitude is divided into N-1 intervals according to the determined amplitude load level coefficient;

[0036] According to the average amplitude interval of the secondary wave, the rain flow counting results are re-statisticed to obtain the (N-1)×(N-1) stress average amplitude circulatory matrix. The same amplitude interval is grouped together, and the group frequency and group mean of each group are calculated.

[0037] Using variable mean statistics, each combination of mean, amplitude and corresponding frequency is used to obtain a test loading program block, with a total of N-1 levels of loading program blocks.

[0038] Optionally, the secondary wave is divided into mean amplitude intervals; wherein the mean is equally divided into N-1 intervals, and the amplitude is divided into N-1 intervals according to the determined amplitude load level coefficient, including:

[0039] Taking the amplitude load level coefficient as the midpoint of the interval, the amplitude interval boundary coefficient is obtained;

[0040] The boundary S of the amplitude interval h is calculated according to the following formula a,edges,q :

[0041] S a,edges,q =S a,max ×C edges,q ;

[0042] Among them, S a,max represents the maximum amplitude; C edges,q Represents the boundary coefficient of the amplitude interval q.

[0043] Optionally, the method of dividing the rainflow counting results according to the average amplitude interval of the secondary wave and re-statistically obtaining a stress average amplitude circulant matrix of (N-1)×(N-1), grouping the groups with the same amplitude interval, and calculating the group frequency and group mean of each group includes:

[0044] The group frequency of each group is calculated according to the following formula:

[0045]

[0046] Among them, V q is the group frequency of amplitude interval q; V pq is the frequency of the mean interval p and amplitude interval q;

[0047] The group mean of each group is calculated according to the following formula:

[0048]

[0049] in, is the group mean of the amplitude interval q; S m,p is the median of the mean interval p.

[0050] Optionally, all the program blocks are arranged in a low-high-low order to obtain a low cycle fatigue program block spectrum as an aircraft engine cold end disk life assessment spectrum, including:

[0051] Divide each block of the secondary wave into two parts of equal frequency;

[0052] The two partial program blocks are arranged on both sides of the zero-maximum-zero program block, where one side of the zero-maximum-zero program block is arranged from small to large according to the maximum value of the program blocks, and the other side is arranged from large to small according to the maximum value of the program blocks, thereby obtaining a low-cycle fatigue program block spectrum of multiple program blocks loaded in a low-high-low load sequence.

[0053] In a second aspect, the present invention provides a system for compiling a life assessment spectrum for a cold end disk of an aircraft engine, comprising:

[0054] An acquisition module, used to obtain N typical mission profiles of an aircraft engine;

[0055] A conversion module for converting the rotational speed of each typical mission profile into stress;

[0056] A cycle counting module is used to count the cycles of each stress using a rain flow counting method to obtain a stress mean amplitude cycle matrix of each typical mission profile as a first stress mean amplitude cycle matrix;

[0057] A weighting module is used to perform task mixing weighting on each first stress mean amplitude circulatory matrix to obtain the stress mean amplitude circulatory matrix of all typical task profiles as the second stress mean amplitude circulatory matrix;

[0058] The first division module is used to divide the cyclic load types in the second stress mean amplitude cyclic matrix into primary waves and secondary waves; wherein, the stress cycle with a minimum value of zero and a maximum value close to the nominal stress at the dangerous point of the aircraft engine cold end disk at the maximum speed is classified as the primary wave, and the remaining stress cycles are all classified as secondary waves;

[0059] The first compilation module is used to compile the main wave into zero-maximum-zero program blocks and perform mean amplitude interval division and variable mean statistics on the secondary wave to form a secondary wave program block parameter table to compile the N-1 level program block;

[0060] The second compilation module is used to arrange all program blocks in the order of low-high-low to obtain a low-cycle fatigue program block spectrum as the life assessment spectrum of the aircraft engine cold end disk.

[0061] The present invention provides a method and system for compiling a life assessment spectrum for the cold end disk of an aero-engine. In the method, a variable mean double-wave method is used to subdivide the load cycle into a primary wave (zero-maximum-zero) and a secondary wave (N-1 level average amplitude interval), comprehensively covering actual operating conditions such as asymmetric cycles and variable mean cycles, breaking through the limitation of the traditional three-cycle spectrum that is only equivalent to three types of cycles. Combining average amplitude interval division and variable mean statistics, the method accurately quantifies the contribution of different cycles to fatigue damage, ensures that the damage accumulation calculation is closer to the actual load distribution, and significantly improves the accuracy of life assessment.

[0062] The block spectrum arrangement technology is used to combine the primary wave and the secondary wave into a multi-level block spectrum in the low-high-low order, which not only simulates the load timing characteristics but also simplifies the test operation. The secondary wave converts the complex continuous load into N-1 discrete loading steps through the discretization of the average amplitude interval (amplitude level coefficient division) and frequency grouping, which greatly reduces the difficulty of controlling the test equipment and improves the loading efficiency and repeatability. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0064] Figure 1 A schematic flow chart of a method for compiling a life assessment spectrum for an aircraft engine cold end disk provided by an embodiment of the present invention;

[0065] Figure 2 A schematic diagram of a typical task profile provided by an embodiment of the present invention;

[0066] Figure 3 A schematic diagram of a stress cross section provided by an embodiment of the present invention;

[0067] Figure 4 A stress mean amplitude cycle matrix diagram provided by an embodiment of the present invention;

[0068] Figure 5 A statistical histogram of stress mean amplitude provided by an embodiment of the present invention;

[0069] Figure 6 A parameter diagram of a main wave program block provided by an embodiment of the present invention;

[0070] Figure 7 An 8×8 stress mean amplitude cycle matrix diagram provided by an embodiment of the present invention;

[0071] Figure 8 A parameter diagram of a secondary wave program block provided by an embodiment of the present invention;

[0072] Figure 9 A spectrum parameter diagram of a low cycle fatigue program block provided by an embodiment of the present invention;

[0073] Figure 10 A schematic diagram of a low cycle fatigue program block spectrum provided by an embodiment of the present invention;

[0074] Figure 11 A schematic diagram of the structure of a system for compiling a life assessment spectrum for an aircraft engine cold end disk provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0075] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0076] Example 1

[0077] like Figure 1 As shown, an embodiment of the present invention provides a method for compiling a life assessment spectrum for an aircraft engine cold end disk, comprising:

[0078] Step 101: Obtain N typical mission profiles of an aircraft engine.

[0079] Exemplarily, N≥3.

[0080] Step 102 : Convert the rotational speed of each typical mission profile into stress.

[0081] In this step, the nominal stress S at the dangerous point of the cold end disk of the aircraft engine at the target speed is calculated illustratively according to the following formula:

[0082]

[0083] Among them, S max is the nominal stress at the dangerous point of the cold end disk of the aircraft engine at the maximum speed; n is the speed of the cold end disk of the aircraft engine; n max It is the maximum speed of the cold end disk of the aircraft engine.

[0084] According to the typical task profiles obtained by the previous clustering, for example, there are 9 typical task profiles, among which a representative typical task profile is as follows Figure 2 As shown in the figure, the task mixing frequency of the 9 typical tasks is assumed to occur 10 times per thousand hours. The speed stress conversion is performed on the typical task profile, and the nominal stress S of the material TC4 of the aircraft engine cold end plate at the maximum speed is max =600Mpa, and the nominal stress corresponding to any speed can be calculated by substituting it into formula (1). The stress profile diagram after conversion is as follows: Figure 3 shown.

[0085] Step 103: Circulation counting of each stress is performed using a rain flow counting method to obtain a stress mean amplitude circulation matrix of each typical mission profile as a first stress mean amplitude circulation matrix.

[0086] In this step, rain flow counting is performed on the stress profile, and the counting results are stored in matrix A. i , i=1,2,…,9; exemplarily, the task mixing M i =10.

[0087] Step 104 : Perform task mixing weighting on each first stress mean amplitude circulatory matrix to obtain the stress mean amplitude circulatory matrix of all typical task profiles as the second stress mean amplitude circulatory matrix.

[0088] For example, the expression of the second stress mean amplitude circulatory matrix A is constructed as follows:

[0089] A=∑(M i ×A i ) (2)

[0090] Among them, M i is the task mixing frequency of the typical task profile i; A i is the stress mean amplitude circulant matrix of the typical mission profile i. According to the mission mixing weighted calculation formula (2), the stress profile rainflow counting results are weighted summed to obtain the matrix A.

[0091] Step 105: Classify the cyclic load types in the second stress mean amplitude cyclic matrix into primary waves and secondary waves; wherein, the stress cycle with a minimum value of zero and a maximum value close to the nominal stress at the dangerous point of the aircraft engine cold end disk at the maximum speed is classified as the primary wave, and the remaining stress cycles are all classified as secondary waves.

[0092] In this embodiment, the variable mean double wave method is used to compile the load program block. Figure 4 and Figure 5 As shown, it can be seen that the stress cycle is concentrated in two regions, with the minimum value being zero and the maximum value being close to S max The stress cycle corresponds to a take-off and landing cycle of the flight mission profile, which plays a dominant role in the fatigue damage to the structure, so it is divided into the main wave; the remaining stress cycles play a secondary role in the fatigue damage to the structure, so they are divided into secondary waves.

[0093] Step 106, compile the main wave into zero-maximum-zero program blocks and divide the secondary wave into average amplitude intervals and perform variable mean statistics to form a secondary wave program block parameter table to compile N-1 level program blocks.

[0094] The cyclic load of the main wave is unified as zero-maximum-zero, and the cyclic frequency of the main wave is V 主波 =∑M i , the main wave program block parameters are as follows Figure 6 shown.

[0095] The secondary wave is divided into mean amplitude intervals; the mean is equally divided into N-1 (8) intervals, and the amplitude is divided into N-1 (8) intervals according to the determined amplitude load level coefficient. The load level coefficient is:

[0096] C=[0,0.125,0.275,0.425,0.575,0.725,0.85,0.95,1].

[0097] Taking the amplitude load level coefficient as the midpoint of the interval, the amplitude interval boundary coefficient is obtained:

[0098] C edges=[0,0.2,0.35,0.5,0.65,0.7875,0.9,0.975,1].

[0099] The boundary S of the amplitude interval h is calculated according to the following formula a,edges,q :

[0100] S a,edges,q =S a,max ×C edges,q (3)

[0101] Among them, S a,max represents the maximum amplitude; C edges,q Represents the boundary coefficient of the amplitude interval q.

[0102] Therefore, the boundaries of the mean interval are: 324MPa, 349MPa, 374MPa, 399MPa, 423MPa, 448MPa, 473MPa, 498MPa, 523MPa.

[0103] According to formula (3), the amplitude interval boundaries are calculated as follows: 0MPa, 28MPa, 50MPa, 71MPa, 93MPa, 112MPa, 128MPa, 139MPa, 142MPa. According to the average amplitude interval division of the secondary wave, the rain flow counting results are re-counted to obtain a new 8×8 stress average amplitude circulatory matrix, as shown in the figure: Figure 7 shown.

[0104] According to the mean amplitude interval division of the secondary wave, the rainflow counting results are re-statisticed to obtain the (N-1)×(N-1) stress mean amplitude circulatory matrix. The groups with the same amplitude interval are grouped together, and the group frequency and group mean of each group are calculated.

[0105] For example, the group frequency of each group is calculated according to the following formula:

[0106]

[0107] Among them, V q is the group frequency of amplitude interval q; V pq is the frequency of the mean interval p and amplitude interval q.

[0108] The group mean of each group is calculated according to the following formula:

[0109]

[0110] in, is the group mean of the amplitude interval q; S m,p is the median of the mean interval p.

[0111] right Figure 7The statistical results are used for variable mean statistics. A column with the same amplitude interval is grouped together. The group frequency is calculated according to formula (4), and the group mean is calculated according to formula (5). Each combination of mean, amplitude and corresponding frequency forms a test loading program block. There are eight levels of load program blocks in total, forming a secondary wave program block parameter table, as shown in Figure 8 shown.

[0112] A load deletion strategy is used to eliminate low-damage loads to avoid redundant tests. This embodiment also includes:

[0113] The second stress mean amplitude cyclic matrix is ​​load deleted according to the maximum amplitude and minimum value of all cycles in the load history to obtain the third stress mean amplitude cyclic matrix.

[0114] Exemplarily, the load deletion threshold Δ is calculated according to the following formula:

[0115] Δ=(G max -G min )·ω (6)

[0116] Among them, G max is the maximum amplitude of all cycles in the load history; G min is the minimum amplitude of all cycles in the load history; ω is a preset constant that can be obtained based on experience. Select ω = 10 and calculate the load deletion threshold Δ = 29.24 MPa according to formula (6); the stress mean amplitude cycle matrix after load deletion of matrix A is as follows: Figure 4 As shown in the figure, the stress mean amplitude statistical histogram is as follows: Figure 5 shown.

[0117] The loads smaller than the load deletion threshold in the second stress mean amplitude circulatory matrix are deleted to obtain a third stress mean amplitude circulatory matrix.

[0118] In the case of the existence of the third stress mean amplitude cyclic matrix, the cyclic load types in the third stress mean amplitude cyclic matrix are divided into primary waves and secondary waves.

[0119] Figure 8 Since the amplitude of the first-level program block is less than the small load deletion threshold, the frequency is zero.

[0120] Step 107 , arrange all the program blocks in the order of low-high-low to obtain a low cycle fatigue program block spectrum, which is used as the life assessment spectrum for the cold end disk of the aircraft engine.

[0121] In this step, each block of the secondary wave is evenly divided into two parts with the same frequency.

[0122] The two partial program blocks are arranged on both sides of the zero-maximum-zero program block, where one side of the zero-maximum-zero program block is arranged from small to large according to the maximum value of the program block, and the other side is arranged from large to small according to the maximum value of the program block. A low-cycle fatigue program block spectrum of multiple (17 in total) program blocks loaded in a low-high-low load sequence is obtained.

[0123] Low cycle fatigue program block spectrum parameter table is as follows Figure 9 As shown, the low cycle fatigue program block spectrum diagram is as follows Figure 10 The low cycle fatigue block spectrum is regarded as the life assessment spectrum of the cold end disk of the aircraft engine.

[0124] In summary, this embodiment provides a method for compiling a life assessment spectrum for the cold end disk of an aircraft engine. By introducing a variable mean double wave method, the load cycle is divided into a primary wave (zero-maximum-zero) and a secondary wave (8-level average amplitude interval), which fully covers different cycle types in actual service (such as asymmetric cycles and variable mean cycles), overcoming the limitation of the traditional three-cycle spectrum that is only equivalent to three types of cycles. Figure 4 Stress mean amplitude cyclic matrix and Figure 5 The statistical histogram of the fatigue damage can accurately quantify the contribution of various cycles to fatigue damage. Figure 8 )Through variable mean statistics and interval division, the load distribution is further refined to ensure that the damage accumulation calculation is closer to the actual working conditions, thereby improving the accuracy of life prediction.

[0125] Using block spectrum arrangement technology, the main wave and secondary wave blocks are combined in the order of low-high-low ( Figure 9 ), forming a 17-level program block spectrum. This arrangement not only simulates the randomness and timing characteristics of the actual load, but also greatly simplifies the complexity of the test loading. For example, the secondary wave program block converts the complex load into a discrete eight-level loading step ( Figure 8 ), significantly reducing the difficulty of controlling the test equipment and improving loading efficiency and repeatability.

[0126] According to the characteristics of the cold end plate components of aircraft engines, a weighted calculation of the mission profile based on speed-stress conversion is proposed, and the low damage loads (such as Figure 4 Data with amplitudes below the threshold are deleted, avoiding ineffective testing. This method addresses the compatibility issues of traditional whole-machine load spectra in component applications, and is particularly suitable for determining and extending the life of key components such as fan impellers and compressor discs.

[0127] Example 2

[0128] Based on the same inventive concept as Example 1, this embodiment further provides a system for compiling a life assessment spectrum for a cold end disk of an aircraft engine. Since the principle of solving the problem by this system is similar to the aforementioned method for compiling a life assessment spectrum for a cold end disk of an aircraft engine, the implementation of this system can refer to the implementation of the method for compiling a life assessment spectrum for a cold end disk of an aircraft engine.

[0129] like Figure 11 As shown in the figure, the aircraft engine cold end disk life assessment spectrum compilation system includes:

[0130] The acquisition module 10 is used to acquire N typical mission profiles of the aircraft engine.

[0131] The conversion module 20 is used to convert the rotation speed of each typical mission profile into stress.

[0132] The cycle counting module 30 is used to count the cycles of each stress using the rain flow counting method to obtain the stress mean amplitude cycle matrix of each typical mission profile as the first stress mean amplitude cycle matrix.

[0133] The weighting module 40 is used to perform task mixing weighting on each first stress mean amplitude circulatory matrix to obtain the stress mean amplitude circulatory matrix of all typical task profiles as the second stress mean amplitude circulatory matrix.

[0134] The first division module 50 is used to divide the cyclic load types in the second stress mean amplitude cyclic matrix into primary waves and secondary waves; wherein, the stress cycle with a minimum value of zero and a maximum value close to the nominal stress at the dangerous point of the cold end disk of the aircraft engine at the maximum speed is divided into the primary wave, and the remaining stress cycles are all divided into secondary waves.

[0135] The first compilation module 60 is used to compile the main wave into zero-maximum-zero program blocks and perform average amplitude interval division and variable mean statistics on the secondary wave to form a secondary wave program block parameter table to compile N-1 level program blocks.

[0136] The second compilation module 70 is used to arrange all program blocks in the order of low-high-low to obtain a low cycle fatigue program block spectrum as the aircraft engine cold end disk life assessment spectrum.

[0137] Illustratively, the aircraft engine cold end disk life assessment spectrum compilation system provided in this embodiment further includes:

[0138] The load deletion module is used to perform load deletion on the second stress mean amplitude circulation matrix according to the maximum amplitude and minimum value of all cycles in the load history to obtain a third stress mean amplitude circulation matrix.

[0139] The second division module is used to divide the cyclic load types in the third stress mean amplitude cyclic matrix into primary waves and secondary waves when there is a third stress mean amplitude cyclic matrix.

[0140] Exemplarily, the load deletion module includes:

[0141] The first calculation unit is configured to calculate a load deletion threshold Δ according to the following formula:

[0142] Δ=(G max -G min )·ω.

[0143] Among them, G max is the maximum amplitude of all cycles in the load history; G min is the minimum amplitude of all cycles in the load history; ω is a preset constant;

[0144] The load deletion unit is used to delete the loads less than the load deletion threshold in the second stress average amplitude circulation matrix to obtain a third stress average amplitude circulation matrix.

[0145] Exemplarily, the conversion module includes:

[0146] The second calculation unit is used to calculate the nominal stress S at the dangerous point of the cold end disk of the aircraft engine at the target speed according to the following formula:

[0147]

[0148] Among them, S max is the nominal stress at the dangerous point of the cold end disk of the aircraft engine at the maximum speed; n is the speed of the cold end disk of the aircraft engine; n max It is the maximum speed of the cold end disk of the aircraft engine.

[0149] Exemplarily, the weighting module includes:

[0150] Construct a unit for constructing the expression of the second stress mean amplitude circulation matrix A:

[0151] A=∑(M i ×A i ).

[0152] Among them, M i is the task mixing frequency of the typical task profile i; A i is the stress mean amplitude circulatory matrix of typical mission profile i.

[0153] Exemplarily, the first compilation module includes:

[0154] The interval division unit is used to divide the secondary wave into mean amplitude intervals; wherein the mean is equally divided into N-1 intervals, and the amplitude is divided into N-1 intervals according to the determined amplitude load level coefficient.

[0155] The first statistical unit is used to divide the rain flow counting results according to the average amplitude interval of the secondary wave, re-statistically obtain the (N-1)×(N-1) stress average amplitude circulatory matrix, and calculate the group frequency and group mean of each group with the same amplitude interval as a group.

[0156] The second statistical unit is used to adopt variable mean statistics to obtain a test loading program block by combining each mean, amplitude and corresponding frequency, with a total of N-1 levels of loading program blocks.

[0157] Exemplarily, the interval division unit includes:

[0158] The determining device is used to obtain the amplitude interval boundary coefficient by taking the amplitude load level coefficient as the midpoint of the interval.

[0159] The first calculation device is used to calculate the boundary S of the amplitude interval h according to the following formula a,edges,q :

[0160] S a,edges,q =S a,max ×C edges,q .

[0161] Among them, S a,max represents the maximum amplitude; C edges,q Represents the boundary coefficient of the amplitude interval q.

[0162] Exemplarily, the first statistical unit includes:

[0163] The second calculating device is used to calculate the group frequency of each group according to the following formula:

[0164]

[0165] Among them, V q is the group frequency of amplitude interval q; V pq is the frequency of the mean interval p and amplitude interval q.

[0166] The third calculating device is used to calculate the group mean of each group according to the following formula:

[0167]

[0168] in, is the group mean of the amplitude interval q; S m,p is the median of the mean interval p.

[0169] Exemplarily, the second compilation module includes:

[0170] A program block division unit is used to evenly divide each program block of the secondary wave into two parts with the same frequency;

[0171] The program block compilation unit is used to arrange two partial program blocks on both sides of the zero-maximum-zero program block, wherein one side of the zero-maximum-zero program block is arranged from small to large according to the maximum value of the program blocks, and the other side is arranged from large to small according to the maximum value of the program blocks, so as to obtain a low-cycle fatigue program block spectrum of multiple program blocks loaded in a low-high-low load sequence.

[0172] For more specific working processes of the above modules, please refer to the corresponding content disclosed in Example 1, which will not be repeated here.

[0173] Example 3

[0174] This embodiment provides a computer device including a processor and a memory; wherein, when the processor executes a computer program stored in the memory, the steps of the method for compiling a life assessment spectrum of an aircraft engine cold end disk described in Example 1 are implemented.

[0175] For more specific details about the above method, please refer to the corresponding content disclosed in Example 1, which will not be repeated here.

[0176] Example 4

[0177] This embodiment provides a computer-readable storage medium for storing a computer program; when the computer program is executed by a processor, the steps of the method for compiling a life assessment spectrum of an aircraft engine cold end disk described in Example 1 are implemented.

[0178] For more specific details about the above method, please refer to the corresponding content disclosed in Example 1, which will not be repeated here.

[0179] Example 5

[0180] This embodiment provides a computer program product, including computer-executable instructions or a computer program. When the computer-executable instructions or the computer program are executed by a processor, the steps of the method for compiling a life assessment spectrum of an aircraft engine cold end disk described in Example 1 are implemented.

[0181] For more specific details about the above method, please refer to the corresponding content disclosed in Example 1, which will not be repeated here.

[0182] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. References to the same or similar parts between the various embodiments will be sufficient. The systems, devices, storage media, and computer program products disclosed in the embodiments correspond to the methods disclosed in the embodiments, so their descriptions are relatively simplified. For relevant details, refer to the method descriptions.

[0183] Those skilled in the art will clearly understand that the techniques in the embodiments of the present invention can be implemented using software plus a necessary general-purpose hardware platform. Based on this understanding, the technical solutions in the embodiments of the present invention, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments of the present invention or certain portions of the embodiments.

[0184] In some embodiments, computer-executable instructions may be in the form of a program, software, software module, script, or code, written in any form of programming language (including compiled or interpreted languages, or declarative or procedural languages), and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

[0185] As an example, computer-executable instructions may, but need not, correspond to a file in a file system, may be stored as part of a file that stores other programs or data, such as in one or more scripts in a HyperText Markup Language (HTML) document, in a single file dedicated to the program in question, or in multiple coordinating files (e.g., files storing one or more modules, subroutines, or code portions).

[0186] By way of example, computer-executable instructions may be deployed to be executed on one electronic device, or on multiple electronic devices located at one site, or on multiple electronic devices distributed across multiple sites and interconnected by a communication network.

[0187] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A method for compiling a life assessment spectrum for an aircraft engine cold end disk, characterized in that: include: Obtain N typical mission profiles of aircraft engines; Convert the rotational speed for each typical mission profile into stress; The rain flow counting method is used to count the cycles of each stress and obtain the stress mean amplitude cycle matrix of each typical mission profile as the first stress mean amplitude cycle matrix; Performing task mixing weighting on each first stress mean amplitude circulation matrix to obtain the stress mean amplitude circulation matrix of all typical task profiles as the second stress mean amplitude circulation matrix; The cyclic load types in the second stress mean amplitude cyclic matrix are divided into primary waves and secondary waves. Among them, the stress cycle with a minimum value of zero and a maximum value close to the nominal stress at the critical point of the aircraft engine cold end disk at the maximum speed is classified as the primary wave, and the remaining stress cycles are all classified as secondary waves. The primary wave is compiled into a zero-maximum-zero program block, and the secondary wave is divided into an average amplitude interval and variable mean value statistics are performed to form a secondary wave program block parameter table to compile an N-1 level program block; All program blocks are arranged in the low-high-low order to obtain the low cycle fatigue program block spectrum, which is used as the life assessment spectrum of the aircraft engine cold end disk.

2. The method for compiling a life assessment spectrum for an aircraft engine cold end disk according to claim 1, characterized in that: Also includes: The load is deleted from the second stress mean amplitude cyclic matrix according to the maximum amplitude and minimum value of all cycles in the load history to obtain the third stress mean amplitude cyclic matrix; In the case of the existence of the third stress mean amplitude cyclic matrix, the cyclic load types in the third stress mean amplitude cyclic matrix are divided into primary waves and secondary waves.

3. The method for compiling a life assessment spectrum for an aircraft engine cold end disk according to claim 2, characterized in that: The method of performing load deletion on the second stress mean amplitude circulatory matrix according to the maximum amplitude and minimum value of all cycles in the load history to obtain a third stress mean amplitude circulatory matrix includes: The load deletion threshold Δ is calculated according to the following formula: Δ=(G max -G min )·oh; Among them, G max is the maximum amplitude of all cycles in the load history; G min is the minimum amplitude of all cycles in the load history; ω is a preset constant; The loads smaller than the load deletion threshold in the second stress mean amplitude circulatory matrix are deleted to obtain a third stress mean amplitude circulatory matrix.

4. The method for compiling a life assessment spectrum for an aircraft engine cold end disk according to claim 1, characterized in that: The conversion of the rotational speed to stress for each typical mission profile includes: The nominal stress S at the dangerous point of the cold end disk of the aircraft engine at the target speed is calculated according to the following formula: Among them, S max is the nominal stress at the dangerous point of the cold end disk of the aircraft engine at the maximum speed; n is the speed of the cold end disk of the aircraft engine; n max It is the maximum speed of the cold end disk of the aircraft engine.

5. The method for compiling a life assessment spectrum for an aircraft engine cold end disk according to claim 1, characterized in that: The step of performing task mixing weighting on each first stress mean amplitude circulatory matrix to obtain stress mean amplitude circulatory matrices of all typical task profiles as the second stress mean amplitude circulatory matrix includes: Construct the expression of the second stress mean amplitude circulation matrix A: A=∑(M i ×A i ); Among them, M i is the task mixing frequency of the typical task profile i; A i is the stress mean amplitude circulatory matrix of typical mission profile i.

6. The method for compiling a life assessment spectrum for an aircraft engine cold end disk according to claim 1, characterized in that: The main wave is compiled into a zero-maximum-zero program block and the secondary wave is divided into an average amplitude interval and a variable mean value is counted to form a secondary wave program block parameter table to compile an N-1 level program block, including: The secondary wave is divided into mean amplitude intervals; wherein the mean is divided into N-1 intervals at equal intervals, and the amplitude is divided into N-1 intervals according to the determined amplitude load level coefficient; According to the average amplitude interval of the secondary wave, the rain flow counting results are re-statisticed to obtain the (N-1)×(N-1) stress average amplitude circulatory matrix. The same amplitude interval is grouped together, and the group frequency and group mean of each group are calculated. Using variable mean statistics, each combination of mean, amplitude and corresponding frequency is used to obtain a test loading program block, with a total of N-1 levels of loading program blocks.

7. The method for compiling a life assessment spectrum for an aircraft engine cold end disk according to claim 6, characterized in that: The secondary wave is divided into mean amplitude intervals; wherein the mean is equally divided into N-1 intervals, and the amplitude is divided into N-1 intervals according to the determined amplitude load level coefficient, including: Taking the amplitude load level coefficient as the midpoint of the interval, the amplitude interval boundary coefficient is obtained; The boundary S of the amplitude interval h is calculated according to the following formula a,edges,q : S a,edges,q =S a,max ×C edges,q ; Among them, S a,max represents the maximum amplitude; C edges,q Represents the boundary coefficient of the amplitude interval q.

8. The method for compiling a life assessment spectrum for an aircraft engine cold end disk according to claim 6, characterized in that: According to the mean amplitude interval division of the secondary wave, the rain flow counting results are re-statisticed to obtain the (N-1)×(N-1) stress mean amplitude circulant matrix, and the same amplitude interval is grouped together to calculate the group frequency and group mean of each group, including: The group frequency of each group is calculated according to the following formula: Among them, V q is the group frequency of amplitude interval q; V pq is the frequency of the mean interval p and amplitude interval q; The group mean of each group is calculated according to the following formula: in, is the group mean of the amplitude interval q; S m,p is the median of the mean interval p.

9. The method for compiling a life assessment spectrum for an aircraft engine cold end disk according to claim 1, characterized in that: All the program blocks are arranged in the order of low-high-low to obtain a low cycle fatigue program block spectrum, which is used as the life assessment spectrum of the aircraft engine cold end disk, including: Divide each block of the secondary wave into two parts of equal frequency; The two partial program blocks are arranged on both sides of the zero-maximum-zero program block, where one side of the zero-maximum-zero program block is arranged from small to large according to the maximum value of the program blocks, and the other side is arranged from large to small according to the maximum value of the program blocks, thereby obtaining a low-cycle fatigue program block spectrum of multiple program blocks loaded in a low-high-low load sequence.

10. A system for compiling life assessment spectrum of cold end disk of aircraft engine, characterized in that: include: An acquisition module, used to obtain N typical mission profiles of an aircraft engine; A conversion module for converting the rotational speed of each typical mission profile into stress; A cycle counting module is used to count the cycles of each stress using a rain flow counting method to obtain a stress mean amplitude cycle matrix of each typical mission profile as a first stress mean amplitude cycle matrix; A weighting module is used to perform task mixing weighting on each first stress mean amplitude circulatory matrix to obtain the stress mean amplitude circulatory matrix of all typical task profiles as the second stress mean amplitude circulatory matrix; The first division module is used to divide the cyclic load types in the second stress mean amplitude cyclic matrix into primary waves and secondary waves; wherein, the stress cycle with a minimum value of zero and a maximum value close to the nominal stress at the dangerous point of the aircraft engine cold end disk at the maximum speed is classified as the primary wave, and the remaining stress cycles are all classified as secondary waves; The first compilation module is used to compile the main wave into zero-maximum-zero program blocks and perform mean amplitude interval division and variable mean statistics on the secondary wave to form a secondary wave program block parameter table to compile the N-1 level program block; The second compilation module is used to arrange all program blocks in the order of low-high-low to obtain a low-cycle fatigue program block spectrum as the life assessment spectrum of the aircraft engine cold end disk.

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