Load spectrum block sorting method considering order effect
By determining the load sequence attribute through rainflow counting and hysteresis loop analysis, and then step-by-step interpolating the load spectrum blocks, the problem of neglecting the load sequence effect in the traditional fatigue spectrum is solved, thus achieving the accuracy of load spectrum block sorting and fatigue life prediction.
Patent Information
- Application Number
- CN202511078761.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-01
- Publication Date
- 2025-11-14
AI Technical Summary
Traditional fatigue spectrum compilation ignores the load sequence effect, leading to errors in fatigue life prediction and failing to accurately reflect stress-strain history and cumulative damage.
Load cycles are extracted by rainflow counting, and the order attribute is determined based on hysteresis hysteresis analysis. The load spectrum blocks are interpolated step by step using parent-child cycle subordination, load level and direction, and sorted by peak/valley value to ensure that the load spectrum block sorting is consistent with the actual flight.
It accurately reconstructs the nested hierarchy of flight loads, reduces the loss of sequence effects, improves the accuracy of fatigue life prediction, adapts to complex flight conditions, and supports the efficient generation and standardization of program spectra.
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Figure CN120951465A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of load spectrum compilation technology for aero-engine structural components, and in particular to a load spectrum block sorting method that considers the order effect. Background Technology
[0002] With the continuous upgrading of aero-engine technology, the complex load spectrum experienced by key structural components (such as fan disks, compressor disks, and turbine disks) during service places higher demands on laboratory life testing and prediction. Traditional fatigue spectrum compilation often focuses on cycle amplitude and cycle number, but frequently ignores the significant impact of load sequence on damage accumulation. In fact, the order of load sequences alters the stress-strain accumulation path of materials at each stage, causing drastically different crack initiation and propagation rates under different sequences of the same amplitude and cycle number, thus directly affecting the accuracy of fatigue life prediction. Therefore, when compiling a program spectrum for life assessment, it is essential to systematically retain or reproduce the sequence of loads under various operating conditions in typical flight missions to truly reflect the stress-strain history and accurately quantify cumulative damage.
[0003] Studies on the load sequence of the program spectrum have shown that the order of load blocks has a significant impact on fatigue life, with the fatigue life of a low-to-high program load spectrum differing from that of a high-to-low program load spectrum by 3 to 4 times. Research on the cumulative fatigue damage under two-stage load tests indicates that the effect of the load sequence on the damage state is not negligible. However, no practically feasible method for ordering program spectrum loads has been provided. To determine the ordering method for fatigue damage assessment loads, fatigue damage assessment loads were arranged in different ordering methods, and the nonlinear cumulative damage under different ordering methods was calculated and compared with the nonlinear damage of the measured load spectrum. The ordering method with the smallest difference was selected as the ordering method for fatigue damage assessment loads in the life test spectrum. However, this method has not been experimentally calibrated, which may lead to prediction errors in nonlinear damage accumulation, and it does not consider the significantly operation-dependent characteristics of aero-engine program spectrum compilation.
[0004] Currently, most fatigue test spectra do not consider the effects of load sequence and load interaction, making it difficult to guarantee that the test spectra are equivalent to the original measured load spectra in terms of damage. However, for aero-engine program spectra with obvious operational characteristics, the original sequence features must be fully considered in order to produce a program spectra that more closely resembles actual flight conditions. Summary of the Invention
[0005] In view of the problems existing in the load spectral block ordering method that considers the order effect, this invention is proposed. Therefore, the problem to be solved by this invention is how to provide a load spectral block ordering method that considers the order effect.
[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:
[0007] In a first aspect, the present invention provides a load spectrum block sorting method that considers the order effect, which includes extracting all load cycles by rainflow counting of the measured load spectrum, and determining the order attribute of each cycle based on hysteresis loop analysis, wherein the order attribute includes the parent-child cycle subordination relationship, load level and load direction.
[0008] The front and rear cycles are divided based on the maximum load point of the flight profile, and the 0-max-0 cycle is used as the first-level reference cycle.
[0009] Insertion is performed step-by-step from high to low load level: Level 2 sub-cycles are directly inserted into Level 1 reference cycles; in the loading half-cycle, the midpoint of the frequency is inserted in ascending order of valley value; in the unloading half-cycle, the midpoint of the frequency is inserted in descending order of peak value. Level 3 sub-cycles are matched with nominal parent cycles. If there are multiple nominal parent cycles for Level 3 sub-cycles, the one with the smallest Euclidean distance from the nominal parent cycle is selected as the final parent cycle. Level 3 cycles without nominal parent cycles are promoted to Level 2 and then re-matched and inserted. Level 4 and lower sub-cycles are recursively processed using Level 3 cycles.
[0010] Multiple sub-blocks at the same level are sorted according to the spectral block mean, with the minimum value placed at the end of the parent loop and the rest inserted at the midpoint of the frequency.
[0011] As a preferred embodiment of the load spectral block sorting method considering the order effect described in this invention, the parent-child cycle dependency relationship of the order attribute is determined by the hysteresis loop inclusion property, specifically: the load history of the child cycle is included in the load-time envelope of the parent cycle, and for child cycles that simultaneously satisfy multiple parent cycle inclusion conditions, the minimum Euclidean distance is used for the final parent cycle matching.
[0012] The load levels are divided according to the nesting depth of the cycles. The first-level cycle corresponds to the main cycle of the flight profile, the second-level cycle is a direct sub-cycle of the first-level cycle, and the third-level cycle is a sub-cycle of the second-level cycle.
[0013] The load direction is defined by the cyclic path direction determined by the rainflow count, with positive cycles marked as positive and negative cycles marked as negative.
[0014] As a preferred embodiment of the load spectral block sorting method considering order effects described in this invention, the step of using the minimum Euclidean distance for final parent cycle matching includes: the Euclidean distance is calculated using the following formula:
[0015]
[0016] Where: d(x) i ,x j Let x be any two points in the dataset. i and x jEuclidean distance, (m) i ,a i ) represents the sample point x i The average amplitude of engine load obtained from the rainflow counting method is statistically analyzed (m). j ,a j ) represents the sample point x j The average amplitude of engine load obtained from the rainflow counting method is statistically analyzed.
[0017] Sub-loops at the same level are sorted in ascending order by valley value in the loading half-loop and in descending order by peak value in the unloading half-loop.
[0018] As a preferred embodiment of the load spectral block sorting method considering the order effect described in this invention, the re-matching and insertion of the third-level cycle without a nominal parent cycle after upgrading to the second level includes: when upgrading the sub-cycle of the unnominated parent cycle, if the original direction conflicts with the back-insertion rule of the target parent cycle, the load direction is adjusted: when the target parent cycle is an increasing half-cycle, the sub-cycle is changed to positive; when the target parent cycle is an unloading half-cycle, the sub-cycle is changed to negative.
[0019] As a preferred embodiment of the load spectral block sorting method considering the order effect described in this invention, the end insertion rule for multiple sub-blocks at the same level is as follows: in the load increase or decrease half-cycle of the parent cycle, calculate the mean of all sub-blocks of the same level, place the sub-block with the smallest mean at the end of the parent cycle, and insert the remaining sub-blocks at 1 / 2 of the parent cycle.
[0020] As a preferred embodiment of the load spectral block sorting method considering the order effect described in this invention, the recursive application of the third-level loop processing for the fourth-level and lower sub-loops includes: first matching the direct parent loop, i.e., the third-level loop; if there is no matching parent loop, it is promoted to the third level and then rematched; the insertion position of all sub-blocks is uniformly set to 1 / 2 of the parent loop.
[0021] In a second aspect, the present invention provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement a load spectral block ordering method that takes into account order effects.
[0022] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements the steps of a load spectral block sorting method that takes into account order effects.
[0023] The beneficial effects of this invention are as follows: In aero-engine load tests, traditional program spectra are only graded according to amplitude magnitude, neglecting the true hierarchical relationship of high-amplitude loads embedding low-amplitude loads. This leads to disordered small-cycle positions and loss of sequence effects during the test, resulting in fatigue life prediction errors. This invention extracts the hysteresis loops of the main and secondary cycles through rainflow counting. Based on the principle of hysteresis loop inclusion, the cycles are divided into first-level main cycles, second-level sub-cycles, third-level sub-cycles, etc., accurately reconstructing the nested hierarchy of flight loads and ensuring that the program spectra are highly consistent with the original flight spectrum in terms of sequence structure. The traditional low-high-low sorting method cannot truly reflect the actual flight of aero-engines and cannot truly reproduce the microscopic effects of residual stress and crack tip closure at the load / unload inflection point, leading to biased fatigue test results. This invention proposes to insert sub-spectrum blocks back at the midpoint of the parent cycle frequency in both the load and unload half-cycles, and sort multiple sub-blocks of the same level by peak / valley values, placing the mildest one at the end. This avoids sequence accumulation and accurately simulates the influence of actual load interactions on the fatigue mechanism. As the flight conditions of aero-engines become increasingly complex, the load levels may far exceed the second and third levels. Therefore, this invention applies the midpoint / end insertion and peak / valley sorting rules recursively to any level of loop, constructing a parameterized and automatically executable spectrum block sorting process. This process can flexibly meet the needs of program spectrum compilation under deeply nested and variable operating conditions, providing solid support for the efficient generation of large flight load spectra and the standardization of fatigue testing. Attached Figure Description
[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 This is a flowchart of the method of the present invention.
[0026] Figure 2 A schematic diagram for determining longitudinal load properties.
[0027] Figure 3 This is a schematic diagram of the back-insertion rules for different cycle directions.
[0028] Figure 4 This is a schematic diagram of the longitudinal load levels.
[0029] Figure 5 A step-by-step diagram illustrating the programming of a sequence based on a sorting method. Detailed Implementation
[0030] To make the above-mentioned objects, features, and advantages of the present invention more readily understood, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.
[0031] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0032] Secondly, the term "one embodiment" or "example" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. An embodiment appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment that selectively excludes other embodiments.
[0033] Example 1
[0034] Reference Figures 1-3 This is the first embodiment of the present invention, which provides a load spectral block ordering method considering order effects, including:
[0035] 1. The core idea of spectrum block sorting is to determine the sorting method of the program spectrum based on the actual hysteresis loop position of typical aero-engine loads. The specific sorting strategy is to treat each lateral load level as a single load, and then insert it back into the reference cycle level by level according to its order attribute from low to high, finally realizing the single load history spectrum block.
[0036] Rainflow counting is performed on the measured load spectrum to extract all load cycles. Hysteresis loop analysis is used to determine the order attributes of each cycle, including the parent-child cycle hierarchy, load level, and load direction.
[0037] Specifically, based on the hysteresis loop, the order attribute of typical characteristic loads is determined. The rainflow counting method is used to extract all cycles from the time history of the measured loads from the preprocessed measured load spectrum. Then, based on the hysteresis loop, the parent-child relationship, load level and load direction of the fatigue loads are extracted to obtain the order attribute of the fatigue loads.
[0038] The parent-child loop dependency relationship of the order attribute is determined by the hysteresis loop inclusion property. Specifically, the load history of the child loop is contained within the load-time envelope of the parent loop. The envelope is extracted by the rainflow counting method from the hysteresis loop in a certain load history interval, which is the boundary line of the upper and lower limit load values of the loop in its time interval. For child loops that simultaneously meet the inclusion conditions of multiple parent loops, the minimum Euclidean distance is used for the final parent loop matching.
[0039] The load levels are divided according to the nesting depth of the cycles. The first-level cycle corresponds to the main cycle of the flight profile, the second-level cycle is a direct sub-cycle of the first-level cycle, and the third-level cycle is a sub-cycle of the second-level cycle.
[0040] The load direction is defined by the direction of the cycle path determined by the rainflow count, with positive cycles marked as positive and negative cycles marked as negative.
[0041] Assume the load history of a certain characteristic load 5-6-5 is as follows Figure 2 As shown, its order attribute exhibits a 4-7-4 sub-cycle in terms of parent-child relationship; a three-level cycle in terms of load level; and an unloading process that first increases and then decreases in load direction. Analysis process and... Figure 2 Similarly, the order attribute of any aero-engine flight profile can be determined by rainflow counting, and the order attribute is unique.
[0042] 2. Divide the front and rear cycles based on the maximum load point of the flight profile, and take the 0-max-0 cycle as the first-level reference cycle;
[0043] In order to conform to the thermal loading path and sequential effects in the actual operation of aero-engines, the back-insertion of each level of the preceding loop must be completed before the back-insertion of each level of the subsequent loop can be performed. In order to balance the hierarchical insertion logic between spectral blocks and the structural integrity of the program spectrum, the child loop must be inserted only after all the parent loops have been back-inserted.
[0044] Specifically, a single load history is formed based on the characteristic load interpolation rules and sequence attributes; the load interpolation rules are determined based on the sequence attributes (e.g., ...). Figure 3 As shown): Determine the reference cycle, take the 0-maximum-0 cycle of each flight profile as the main cycle, and regard the main cycle as the first-level longitudinal load cycle, as the reference load for all typical cycle back-interpolation.
[0045] The secondary load cycles are then inserted back into the reference cycle. All secondary load cycles are necessarily sub-cycles of the reference load cycle. Their relative positions within the primary load cycles are determined based on the load magnitude, and the load spectrum shape after insertion is determined based on the cycle direction. The relative positions refer to the order of multiple sub-cycles within the parent cycle, with the maximum value (σ) of the typical characteristic cycle used in the load-increasing half-cycle. max =σ m+σ a The criterion is to use the smallest value first, then the largest; while in the load reduction half-cycle, the minimum value of the typical characteristic cycle (σ) is used as the criterion. max =σ m -σ a Using the largest as the criterion, proceed from largest to smallest.
[0046] Determining if a parent loop exists in a third-level cycle: Based on the load size, determine if a second-level parent loop exists for the third-level typical characteristic load. Assume the size of a certain second-level typical characteristic load is (σ... max ,σ min The typical load size for level three is (σ'). max ,σ' min If σ exists min ≥σ' min And σ max ≤σ' max If the secondary typical characteristic loads meet the conditions, then the secondary typical loads that meet the conditions will be regarded as the nominal parent cycle of the tertiary typical loads currently being analyzed, and the rest will be classified as tertiary typical loads without nominal parent cycles.
[0047] For tertiary loops with parent loops, back-insertion is performed: based on the back-insertion rule, tertiary typical characteristic loads are inserted into secondary typical characteristic loads. If a tertiary typical load has multiple nominal parent loops, the one with the smallest Euclidean distance from the real parent loop is selected as the final choice. The distance calculation formula is as follows:
[0048]
[0049] Where: d(x) i ,x j Let x be any two points in the dataset. i and x j Euclidean distance, (m) i ,a i ) represents the sample point x i The average amplitude of engine load obtained from the rainflow counting method is statistically analyzed (m). j ,a j ) represents the sample point x j The average amplitude of engine load obtained from the rainflow counting method is statistically analyzed.
[0050] Sub-loops at the same level are sorted in ascending order by valley value in the loading half-loop and in descending order by peak value in the unloading half-loop.
[0051] For third-level cycles without a parent cycle, back-insertion is performed: after upgrading its load level to second-level, it is back-inserted into the first-level reference cycle according to the second-level cycle back-insertion rules. It should be noted that the upgraded third-level typical characteristic load may change its original cycle direction to meet the insertion rules of the second-level load cycle.
[0052] Reinsert the remaining lower-level loads: Analyze the typical characteristic loads of levels four and five, and the processing method is the same as that for level three typical characteristic loads.
[0053] 3. Single load history spectral blockization: The single load history is spectral blockized by removing the repetitions of the cycle count according to the rainflow counting method. Multiple sub-blocks at the same level are sorted according to the average value of the spectral blocks, with the minimum value placed at the end of the parent cycle and the rest inserted at the midpoint of the load spectral block.
[0054] Specifically, in the load increase half-cycle, the lower-level typical loads are all inserted back to 1 / 2 of the previous level typical load spectrum block; in the load decrease half-cycle, the lower-level typical loads are inserted back to 1 / 2 of the previous level typical load spectrum block. If there are multiple loads of the same level, the average value of the spectrum block is used as the judgment standard. The one with the smallest average value is inserted back to the end of the previous level typical load, and the rest are inserted back to 1 / 2 of the previous level typical load spectrum block.
[0055] Example 2
[0056] Reference Figures 1-5 This is the first embodiment of the present invention, which provides a load spectral block ordering method considering order effects, including:
[0057] Using the preprocessed load spectrum of 37 measured profiles of the compressor disk of the X-type third-generation aero-engine as the raw data, and taking the time point of maximum load in the flight profile as the dividing line, the load history was divided into the pre-cycle and post-cycle. The characteristic loads and frequencies of the pre-cycle and post-cycle are shown in Table 1.
[0058] Table 1 Summary of Typical Characteristic Load Information
[0059]
[0060] The longitudinal load level is not a true load history, but rather a load cycle hierarchy determined in reverse based on rainflow count results. Taking the typical characteristic load F2 of the previous cycle as an example, F2 is in the 0-max process of the reference cycle, but it is not directly included in the reference cycle (0-max-0). Instead, it is included in the 'load reduction' process of a positive load in the 0-max process of the reference cycle. The longitudinal load history is as follows: Figure 4 As shown in (b). Therefore, its parent cycle is a second-order longitudinal load, F2 is determined to be a third-order longitudinal load, and its cycle direction is determined to be a negative load according to the rainflow counting principle, denoted by -.
[0061] The analysis process is the same, and the longitudinal load levels of the eight typical characteristic loads are as follows: Figure 4 As shown, where Figure 4 (a) to (d) represent the longitudinal load level information for the previous cycle. Figure 4(e) to (h) represent the load level information for the subsequent cycles. A summary of the order attributes of all characteristic load levels is shown in Table 1.
[0062] Construct program spectrum blocks, define insertion rules, and comprehensively consider the lateral and longitudinal load information of typical characteristic loads. Generate program spectra in the order of previous loops followed by subsequent loops. In the previous loop, the longitudinal load levels of F1 and F3 are both level two, and since there is no need to consider load escalation or de-escalation, they should be given priority, with the load with the smaller maximum value preceding the previous one. The maximum value of F1 load... F3 maximum load satisfy Therefore, in the program spectrum, F1 is generated first, followed by F3. In the remaining two pre-loops, the third-level load U2 is generated first, followed by the fourth-level load F4. In the post-loop, there are simultaneously second-level (B2), third-level (B4), and fourth-level (B1, B3) longitudinal load levels. In the post-loop of the program spectrum, B2 is generated first, followed by B4, and finally B1 and B3. Among them, the third-level load B4 satisfies the inclusion condition of being the nominal parent loop of both B1 and B3. Since the average value of B3 load is less than that of B1, according to the program spectrum block sorting strategy, B1 is inserted back at the end of the B4 block, and B3 is inserted back in the middle of the B4 block.
[0063] The lifetime test spectrum considering the order effect was compiled based on the back-insertion rule.
[0064] Based on the number of characteristic loads in Table 1, the load history spectra for each load level are block-based. Then, based on the interpolation rule, the life test spectrum considering the order effect is compiled. The specific compilation process is as follows: Figure 5 As shown.
[0065] This embodiment also provides a computer device applicable to a load spectral block ordering method considering order effects, comprising: a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions to implement all or part of the steps of the method described in the above embodiments of the present invention.
[0066] This embodiment also provides a storage medium on which a computer program is stored. When the computer program is executed by a processor, it performs the method in any optional implementation of the above embodiments. The storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.
[0067] The storage medium proposed in this embodiment and the data storage method proposed in the above embodiments belong to the same inventive concept. Technical details not described in detail in this embodiment can be found in the above embodiments, and this embodiment has the same beneficial effects as the above embodiments.
[0068] In summary, in aero-engine load testing, traditional program spectra are only graded by amplitude magnitude, neglecting the true hierarchical relationship of high-amplitude loads embedding low-amplitude loads. This leads to disordered small-cycle positions and loss of sequence effects during testing, resulting in fatigue life prediction errors. This invention extracts the hysteresis loops of the main and secondary cycles through rainflow counting. Based on the hysteresis loop inclusion principle, the cycles are divided into first-level main cycles, second-level sub-cycles, third-level sub-cycles, etc., accurately reconstructing the nested hierarchy of flight loads and ensuring that the program spectra are highly consistent with the original flight spectrum in terms of sequence structure. The traditional low-high-low sorting method cannot accurately reflect the actual flight of aero-engines and cannot realistically reproduce the microscopic effects of residual stress and crack tip closure at the load / unload inflection point, leading to biased fatigue test results. This invention proposes inserting sub-spectrum blocks back at the midpoint of the parent cycle frequency in both the load and unload half-cycles, and sorting multiple sub-blocks at the same level by peak / valley values, placing the mildest one at the end. This avoids sequence accumulation and precisely simulates the influence of actual load interactions on the fatigue mechanism. As the flight conditions of aero-engines become increasingly complex, the load levels may far exceed the second and third levels. Therefore, this invention applies the midpoint / end insertion and peak / valley sorting rules recursively to any level of loop, constructing a parameterized and automatically executable spectrum block sorting process. This process can flexibly meet the needs of program spectrum compilation under deeply nested and variable operating conditions, providing solid support for the efficient generation of large flight load spectra and the standardization of fatigue testing.
[0069] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A load spectral block ordering method considering order effects, characterized in that: include, Rainflow counting is performed on the measured load spectrum to extract all load cycles. Hysteresis loop analysis is used to determine the order attributes of each cycle, including the parent-child cycle hierarchy, load level, and load direction. The front and rear cycles are divided based on the maximum load point of the flight profile, and the 0-max-0 cycle is used as the first-level reference cycle. Insertion is performed step-by-step from high to low load level: Level 2 sub-cycles are directly inserted into Level 1 reference cycles; in the loading half-cycle, the midpoint of the frequency is inserted in ascending order of valley value; in the unloading half-cycle, the midpoint of the frequency is inserted in descending order of peak value. Level 3 sub-cycles are matched with nominal parent cycles. If there are multiple nominal parent cycles for Level 3 sub-cycles, the one with the smallest Euclidean distance from the nominal parent cycle is selected as the final parent cycle. Level 3 cycles without nominal parent cycles are promoted to Level 2 and then re-matched and inserted. Level 4 and lower sub-cycles are recursively processed using Level 3 cycles. Multiple sub-blocks at the same level are sorted according to the spectral block mean, with the minimum value placed at the end of the parent loop and the rest inserted at the midpoint of the frequency.
2. The load spectral block ordering method considering order effects as described in claim 1, characterized in that: The parent-child loop dependency relationship of the order attribute is determined by the hysteresis loop inclusion property, specifically: the load history of the child loop is included in the load-time envelope of the parent loop. For a child loop that simultaneously satisfies the inclusion condition of multiple parent loops, the minimum Euclidean distance is used for the final parent loop matching. The load levels are divided according to the nesting depth of the cycles. The first-level cycle corresponds to the main cycle of the flight profile, the second-level cycle is a direct sub-cycle of the first-level cycle, and the third-level cycle is a sub-cycle of the second-level cycle. The load direction is defined by the cyclic path direction determined by the rainflow count, with positive cycles marked as positive and negative cycles marked as negative.
3. The load spectral block sorting method considering order effects as described in claim 2, characterized in that: The method of using minimum Euclidean distance for final parent loop matching includes: the formula for calculating Euclidean distance is as follows: Where: d(x) i ,x j Let x be any two points in the dataset. i and x j Euclidean distance, (m) i ,a i ) represents the sample point x i The average amplitude of engine load obtained from the rainflow counting method is statistically analyzed (m). j ,a j ) represents the sample point x j The average amplitude of engine load obtained from the rainflow counting method is statistically analyzed. Sub-loops at the same level are sorted in ascending order by valley value in the loading half-loop and in descending order by peak value in the unloading half-loop.
4. The load spectral block sorting method considering order effects as described in claim 3, characterized in that: The process of upgrading a third-level loop without a nominal parent loop to a second-level loop and then re-matching and inserting it includes: when upgrading a child loop without a nominal parent loop, if the original direction conflicts with the target parent loop's back-insertion rule, the load direction is adjusted: when the target parent loop is an increasing half-loop, the child loop is changed to positive; when the target parent loop is an unloading half-loop, the child loop is changed to negative.
5. The load spectral block sorting method considering order effects as described in claim 4, characterized in that: The rule for inserting multiple sub-blocks at the same level at the end is as follows: In the half-cycle of increasing or decreasing load of the parent loop, calculate the average value of all sub-blocks at the same level, place the sub-block with the smallest average value at the end of the parent loop, and insert the remaining sub-blocks at 1 / 2 of the parent loop.
6. The load spectral block sorting method considering order effects as described in claim 5, characterized in that: The recursive application of the third-level loop to the fourth-level and lower sub-loops includes: first matching the direct parent loop, i.e., the third-level loop; if there is no matching parent loop, it is promoted to the third level and then rematched; the insertion position of all sub-blocks is uniformly set to 1 / 2 of the parent loop.
7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the load spectral block sorting method considering the order effect as described in any one of claims 1 to 6.
8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the load spectral block sorting method considering the order effect as described in any one of claims 1 to 6.