Method and device for searching stress extreme point, electronic equipment and storage medium

Abstract

The invention provides a method and device for searching a stress extreme point, electronic equipment and a storage medium, and relates to the field of pressure vessel stress analysis, and the method for searching the stress extreme point comprises the steps: carrying out the elastic stress analysis of a pressure vessel bearing a cyclic load, and obtaining a first stress sequence; connecting the first stress sequence end to end to form a stress process cycle to obtain a second stress sequence; deleting equal stress components of adjacent comparison time points in the second stress sequence, and retaining the stress component of the first comparison time point to obtain a third stress sequence; and performing trend vector comparison on the stress components in the third stress sequence to obtain a stress extreme point sequence. The accuracy of searching the stress extreme point is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of stress analysis of pressure vessels, in particular to a method and device for searching stress extreme points, electronic equipment and storage medium. BACKGROUND

[0002] In the design and operation of pressure vessels, fatigue life and stability assessment of pressure vessels is a key link to ensure their long-term safe operation. When evaluating the fatigue life and stability of pressure vessels according to the results of elastic stress analysis, it is necessary to count all effective stress amplitudes and corresponding stress cycle times according to the stress history. The specification recommends the "rainflow method" or "maximum minimum cycle method" counting method, and the effective execution of the method requires accurate identification of stress extreme points in the stress history.

[0003] The prior art converts the change of multi-axis stress components with time into the change of a single equivalent value with time to search for each stress extreme point in the time history. This method is effective in stress history caused by proportional loading. However, in the process of non-proportional loading, the changes of each stress component with time are not synchronized, or even if they are synchronized, the change of the principal stress direction may still occur, making it difficult to determine the stress extreme point according to the single stress value after equivalent processing. The direction change is easily misjudged as an amplitude extreme value, resulting in the appearance of pseudo extreme points and affecting the accuracy of stress extreme point determination. SUMMARY

[0004] The problem solved by the present application is how to improve the accuracy of searching for stress extreme points.

[0005] To solve the above problems, the present application provides a method and device for searching stress extreme points, electronic equipment and storage medium.

[0006] In a first aspect, the present application provides a method for searching stress extreme points, comprising: performing elastic stress analysis on a pressure vessel subjected to cyclic loading to obtain a first stress sequence; connecting the first stress sequence at the beginning and the end to form a stress history cycle to obtain a second stress sequence; deleting equal stress components of adjacent comparison time points in the second stress sequence and retaining the stress component of the first comparison time point to obtain a third stress sequence; comparing the stress components in the third stress sequence by trend vector to obtain a stress extreme point sequence.

[0007] Optionally, the elastic stress analysis on the pressure vessel subjected to cyclic loading to obtain the first stress sequence comprises: The stress components at each analysis time point in the elastic stress analysis process of the pressure vessel subjected to the cyclic load are extracted, and the first stress sequence is formed according to the order of the analysis time points.

[0008] Optionally, the cyclic load comprises at least one complete load history.

[0009] Optionally, the first stress sequence is connected at the head and tail to form a stress history cycle to obtain a second stress sequence, comprising: The stress component at the second last analysis time point in the first stress sequence is added before the first analysis time point in the first stress sequence to obtain the second stress sequence. The first stress sequence is connected at the head and tail to form a stress history cycle to obtain a second stress sequence, comprising: The stress component at the first analysis time point in the first stress sequence is replaced by the stress component at the last analysis time point in the first stress sequence. The stress component at the second last analysis time point in the first stress sequence is added at the front end of the first stress sequence to obtain the second stress sequence.

[0010] Optionally, the equal stress components of adjacent comparison time points in the second stress sequence are deleted, and the stress component of the first comparison time point is retained to obtain a third stress sequence, comprising: The stress components of adjacent comparison time points in the second stress sequence are compared. When the stress component at the first comparison time point in the second stress sequence is equal to the stress component at the second comparison time point, the stress component at the second comparison time point in the second stress sequence is deleted to obtain the third stress sequence, wherein the first comparison time point is the former one of the adjacent comparison time points, the second comparison time point is the latter one of the adjacent comparison time points, and the stress components of adjacent comparison time points in the third stress sequence are not equal.

[0011] Optionally, the stress extreme point sequence is obtained by comparing the stress components in the third stress sequence with a trend vector, comprising: A first change amount between the stress component at a first comparison time point and the stress component at a second comparison time point in the third stress sequence is obtained, and a first trend vector is determined by using a sign function to determine the sign of the first change amount, wherein the first comparison time point and the second comparison time point are adjacent, and the first comparison time point is earlier than the second comparison time point. obtaining a second change amount between a stress component of the second comparison time point and a stress component of a third comparison time point, determining a sign of the second change amount using a sign function, obtaining a second trend vector, the second comparison time point being adjacent to the third comparison time point, and the second comparison time point being earlier than the third comparison time point; obtaining a difference vector between the first trend vector and the second trend vector; when an absolute value of each component of the difference vector is less than or equal to 1, deleting the stress component of the second comparison time point in the third stress sequence until a fourth stress sequence is obtained; obtaining the stress extreme point sequence according to the fourth stress sequence.

[0012] Optionally, a stress component of a first remaining time point in the fourth stress sequence is equal to a stress component of a first comparison time point in the third stress sequence, a stress component of a last remaining time point in the fourth stress sequence is equal to a stress component of a last comparison time point in the third stress sequence, and the obtaining the stress extreme point sequence according to the fourth stress sequence comprises: deleting the stress component of the first remaining time point in the fourth stress sequence and the stress component of the last remaining time point in the fourth stress sequence to obtain the stress extreme point sequence.

[0013] In a second aspect, the present application provides a device for searching stress extreme points, comprising: an analysis module configured to perform elastic stress analysis on a pressure vessel subjected to cyclic loading to obtain a first stress sequence; an adding module configured to connect the first stress sequence at its head and tail to form a stress history cycle to obtain a second stress sequence; a first comparison and deletion module configured to delete equal stress components of adjacent comparison time points in the second stress sequence and retain a stress component of a first comparison time point to obtain a third stress sequence; a second comparison and deletion module configured to obtain a stress extreme point sequence by comparing trend vectors of stress components in the third stress sequence.

[0014] In a third aspect, the present application provides an electronic device comprising a memory and a processor; the memory is configured to store a computer program; the processor is configured to implement the method for searching stress extreme points according to the first aspect when executing the computer program.

[0015] In a fourth aspect, the present application provides a computer readable storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by a processor, the method for searching stress extreme points according to the first aspect is implemented.

[0016] The searching stress extreme points of the present application has the following advantages: through elastic stress analysis on the pressure vessel subjected to cyclic load, the multi-axial stress components of the pressure vessel at different time points are obtained. Under non-proportional loading (such as even if synchronous loading, the stress caused by thermal load may lag behind the stress caused by mechanical load, or the direction of pure pressure load changes), the principal stress direction may change, and if equivalent stress (such as equivalent stress or stress intensity) is used, false extreme points may be generated due to the loss of direction information. By directly obtaining multi-axial stress components instead of equivalent stress, the complete stress state information is retained, false judgment is avoided, and the accuracy of obtaining stress extreme points is further ensured. By connecting the first stress sequence at the beginning and the end to construct a cyclic sequence, the boundary problem of extreme value identification of the first and last points under periodic load is solved. In the traditional method, the first and last points are difficult to determine whether they are extreme points due to the lack of adjacent points before and after them. The first stress sequence forms a closed loop, so that the extreme value judgment logic of the first and last regions is consistent with that of the middle region, and the integrity and accuracy of determining extreme points are improved. Under long-time steady-state working conditions, the stress of multiple time points may be constant, and by deleting adjacent repeated time points, data redundancy is reduced and calculation efficiency is improved. Based on the comparison of trend vectors, the change direction of the multi-axial stress component is determined to determine the extreme point, which can accurately determine the stress extreme point, avoid the uncertainty of artificially setting coefficients and thresholds, and thus improve the accuracy of extreme point search. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 Fig. 1 is a flowchart of the method for searching stress extreme points in the embodiment of the present application; Figure 2 Fig. 2 is a structural block diagram of the device for searching stress extreme points in the embodiment of the present application; Figure 3 Fig. 3 is a structural diagram of an electronic device in the embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms, and should not be interpreted as being limited to the embodiments described herein, on the contrary, these embodiments are provided to make the present application more thorough and complete. It should be understood that the drawings and embodiments of the present application are only for illustrative purposes, and are not intended to limit the scope of protection of the present application.

[0019] It should be understood that each of the steps recited in the method embodiments of the present application can be performed in different orders and / or in parallel. In addition, the method embodiments can include additional steps and / or omit performing the steps shown. The scope of the present application is not limited in this regard.

[0020] The term "comprises" and variations thereof herein are open-ended, that is, "comprising but not limited to"; the term "based on" is, at least based on part on; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optional" means "optional in at least some embodiments". Related definitions are given throughout the detailed description. It is to be noted that the concepts mentioned in the present application are merely illustrative and not restrictive, and those skilled in the art should understand that "one" "multiple" modification is illustrative and not restrictive, and unless otherwise explicitly indicated in the context, it should be understood as "one or more".

[0021] It should be noted that the modification of "one" "multiple" mentioned in the present application is illustrative and not restrictive, and those skilled in the art should understand that unless otherwise explicitly indicated in the context, it should be understood as "one or more".

[0022] The names of the messages or information exchanged between the devices in the embodiments of the present application are only for illustrative purposes, and are not intended to limit the scope of the messages or information.

[0023] In the related art, during the non-proportional loading process, it is difficult to determine the stress extreme point according to the single stress value after equivalent processing, and the direction change is easily misjudged as the amplitude extreme value, resulting in the appearance of pseudo extreme points. Although some improved methods attempt to introduce window search or manually set threshold to correct, they are easily affected by subjective factors due to the dependence on empirical parameters, and it is difficult to achieve accurate and reliable extreme point determination.

[0024] To solve the problems in the above related art, the present embodiment provides a method, device, electronic equipment and storage medium for searching stress extreme points.

[0025] As shown in Figure 1 The method for searching stress extreme points provided by the present embodiment includes: S100, performing elastic stress analysis on the pressure vessel subjected to cyclic loading to obtain a first stress sequence; Specifically, the elastic stress analysis of the pressure vessel can be performed using a structural finite element analysis software, and the stress data of a certain stress linearization path (for example, the stress data of the pressure vessel structure discontinuity) on the pressure vessel can be extracted. In the elastic stress analysis, the stress state changes with time, and the stress components at each time point are obtained, represents the stress component at the i-th time point, and the stress sequence is constituted in time sequence , , ,…, , which is the first stress sequence.

[0026] S200, the first stress sequence is connected at the head and tail to form a stress history cycle, and a second stress sequence is obtained; Specifically, the stress component at the second-to-last analysis time point of the first stress sequence is added before the first analysis time point of the first stress sequence to form a closed stress history cycle. That is, the first stress sequence is , , ,…, , and is added before to form a new stress sequence , , , ,…, , and the sequence is rearranged to obtain the second stress sequence, that is , , ,…, , wherein m=n+1.

[0027] S300, the equal stress components of adjacent comparison time points in the second stress sequence are deleted, and the stress component of the first comparison time point is retained to obtain a third stress sequence; Specifically, the stress vectors of adjacent time points in the second stress sequence ( , , ,…, ) are compared, the equal stress components of adjacent time points in the second stress sequence are deleted, and the first appearing stress component is retained, for example, when S i = S i+1 , then S i+1 is deleted from the sequence, and S i is retained, and S i and S i+2 are compared, until any two adjacent stress vectors in the sequence are not equal, and the third stress sequence S 1, S 2, S 3, … S x is obtained by rearranging the sequence.

[0028] S400, by comparing the stress components in the third stress sequence with trend vectors, a stress extreme point sequence is obtained.

[0029] Specifically, for the stress components at each comparison time point in the third stress sequence S i Calculate its stress components compared to the previous comparison time point. S i-1 The trend vector, and the stress components compared to the next time point. S i+1 The trend vector is calculated. The change in two adjacent trend vectors is calculated, and the stress extrema points are identified based on the changes. Redundant time points between the two stress extrema points are removed to obtain the stress extrema point sequence.

[0030] In this embodiment, elastic stress analysis is performed on a pressure vessel subjected to cyclic loads to obtain the multiaxial stress components of the pressure vessel at different time points. Under non-proportional loading (such as when the stress caused by thermal load lags behind the stress caused by mechanical load even with synchronous loading, or when the direction of the pressure load simply changes), the direction of the principal stress may change. If equivalent stress (such as equivalent stress or stress intensity) is used, pseudo-extreme points will be generated due to the loss of direction information. By directly obtaining the multiaxial stress components instead of equivalent stress, complete stress state information is preserved, misjudgment is avoided, and the accuracy of obtaining stress extreme points is further ensured. By connecting the first and last stress sequences to construct a cyclic sequence, the boundary problem of identifying extreme points at the first and last points under periodic loads is solved. In traditional methods, it is difficult to determine whether the first and last points are extreme points due to the lack of adjacent points. Forming the first stress sequence into a closed loop makes the extreme point judgment logic of the first and last regions consistent with that of the middle region, improving the completeness and accuracy of determining extreme points. Under long-term steady-state conditions, the stress may remain unchanged at multiple consecutive time points. By deleting adjacent repeated time points, data redundancy is reduced and computational efficiency is improved. Determining extreme points by comparing trend vectors to identify abrupt changes in the direction of multiaxial stress components can accurately identify stress extreme points, avoiding the uncertainty of manually set coefficients and thresholds, thereby improving the accuracy of extreme point search.

[0031] Optionally, the step of performing elastic stress analysis on the pressure vessel subjected to cyclic loads to obtain a first stress sequence includes: The stress components at each analysis time point during the elastic stress analysis of the pressure vessel subjected to cyclic loads are extracted, and the first stress sequence is constructed according to the order of the analysis time points.

[0032] In particular, in the elastic stress analysis of a pressure vessel subjected to cyclic loading, the stress state changes over time, and all stress components at each analysis time point in the elastic stress analysis of the pressure vessel subjected to cyclic loading are extracted, represents the stress component at the i th time point, [ , , , , , ] wherein, represents the normal stress component in the x direction, represents the normal stress component in the y direction, represents the normal stress component in the z direction, represents the shear stress component in the y direction in the plane perpendicular to the x axis, the shear stress component in the xy plane, represents the shear stress component in the z direction in the plane perpendicular to the y axis, the shear stress component in the yz plane, represents the shear stress component in the z direction in the plane perpendicular to the x axis, the shear stress component in the xz plane. A sequence is formed in time order , , , , that is, a first stress sequence.

[0033] In this optional embodiment, the directionality and multi-axiality of the stress state are preserved by extracting all stress components at each analysis time point rather than equivalent stress (such as equivalent stress or stress intensity). In a non-proportional loading condition (such as a thermal stress with a different phase than a mechanical stress), the stress components change out of sync over time, or even if they change in sync, it can cause the direction of the principal stress to change, resulting in misjudgment of the extreme point (such as mistaking the direction change for the amplitude change). By preserving all components, the authenticity of subsequent extreme value identification is ensured, and the accuracy and reliability of determining stress extreme points are improved.

[0034] Optionally, the load includes an alternating load, and the alternating cyclic load includes at least one complete load history.

[0035] Specifically, the alternating cyclic load refers to a load whose magnitude and direction periodically change over time, such as the pressure fluctuation, vibration load, and inertial force caused by reciprocating motion that the pressure vessel bears during operation, and the complete load history refers to the process from the start of the load to the completion of a periodic change. For example, an alternating load cycle of a sinusoidal waveform, from zero to maximum, then decreasing to zero, then increasing to a minimum, and finally returning to zero, constitutes a complete load history. The cyclic load borne by the pressure vessel needs to include at least one complete load history to ensure that the extracted stress history contains a complete stress cycle. In this optional embodiment, the cyclic load borne by the pressure vessel during operation is periodically changed, and the cyclic load applied to the pressure vessel includes at least one complete load history, ensuring that the extracted stress history contains at least one complete stress cycle, thereby ensuring the accuracy and reliability of the stress extreme points.

[0036] Optionally, the first stress sequence is connected at the beginning and the end to form a stress history cycle to obtain a second stress sequence. The stress component at the second-to-last analysis time point in the first stress sequence is added before the first analysis time point in the first stress sequence to obtain the second stress sequence.

[0037] Specifically, the first stress sequence is , , , …, The first stress sequence is added at the beginning to form a new stress sequence , , , , , …, The second stress sequence is obtained by rearranging the sequence , , , …, , wherein m = n + 1.

[0038] In an embodiment, the stress component at the first analysis time point of the first stress sequence is replaced by the stress component at the last analysis time point of the first stress sequence, and the stress component at the second-to-last analysis time point in the first stress sequence is added before the first analysis time point of the first stress sequence. (The order of the statements is reversed to prevent ambiguity) The stress component at the first analysis time point of the first stress sequence is replaced by the stress component at the last analysis time point of the first stress sequence, and the second stress sequence obtained is: , , , ,…, The second stress sequence is obtained by rearranging the sequence. , , ,…, Where m=n+1, the stress component at the first analysis time point of the first stress sequence is replaced with the stress component at the last analysis time point of the first stress sequence to ensure that the stress component at the last time point can be used to determine the stress extremum point and to eliminate the influence of the slight difference in stress components at the first and last time points caused by numerical calculation errors.

[0039] In this optional embodiment, by connecting the first stress sequence end to end to construct a stress history cycle, the boundary problem of identifying the extreme values ​​at the beginning and end points under periodic loads is solved. By forming a closed loop with the first stress sequence, the extreme value judgment of the beginning and end regions of the first stress sequence is consistent with that of the middle region, thereby improving the completeness and consistency of extreme value identification.

[0040] Optionally, the step of deleting equal stress components at adjacent comparison time points in the second stress sequence and retaining the stress component at the first comparison time point to obtain the third stress sequence includes: Compare the stress components at adjacent comparison time points in the second stress sequence; When the stress component at the first comparison time point in the second stress sequence is equal to the stress component at the second comparison time point, the stress component at the second comparison time point is deleted from the second stress sequence to obtain the third stress sequence. Here, the first comparison time point is the previous comparison time point among adjacent comparison time points, the second comparison time point is the next comparison time point among adjacent comparison time points, and the stress components at adjacent comparison time points in the third stress sequence are not equal.

[0041] Specifically, comparing the second stress sequence ( , , ,…, The stress vectors at two adjacent comparison time points, if S i = S i+1 Then delete from the sequence. S i+1 ,reserve S i Continue the comparison S i and S i+2 until and S i The stress components in comparison with S i When they are not equal. IfS i is not equal to S i+1 , then compare S i+1 and S i+2 , until the stress components of each comparison time point in the second stress sequence are all compared, when the two adjacent stress vectors in the sequence are not equal, the sequence is rearranged to obtain a third stress sequence S 1, S 2, S 3, … S x， The stress components of adjacent time points in the third stress sequence are all not equal. Among them, in order to distinguish, the time points in the first stress sequence are named as analysis time points, and the time points in the second stress sequence are named as comparison time points.

[0042] In the optional embodiment, under the working condition of long-time steady-state load, the stress of multiple consecutive time points may be unchanged, and the data redundancy is reduced and the calculation efficiency is improved by deleting the stress components of adjacent repeated comparison time points and retaining the stress components of the first time point in adjacent repeated time points.

[0043] Optionally, the stress extreme point sequence is obtained by comparing the stress components in the third stress sequence with trend vectors, comprising: obtaining a first change quantity between the stress components of a first comparison time point and the stress components of a second comparison time point in the third stress sequence, determining the sign of the first change quantity using a sign function to obtain a first trend vector, the first comparison time point and the second comparison time point are adjacent, and the first comparison time point is earlier than the second comparison time point; obtaining a second change quantity between the stress components of the second comparison time point and the stress components of a third comparison time point, determining the sign of the second change quantity using a sign function to obtain a second trend vector, the second comparison time point and the third comparison time point are adjacent, and the second comparison time point is earlier than the third comparison time point; obtaining a difference vector between the first trend vector and the second trend vector; when the absolute value of each component of the difference vector is less than or equal to 1, deleting the stress components of the second comparison time point in the third stress sequence, until a fourth stress sequence is obtained; obtaining the stress extreme point sequence according to the fourth stress sequence.

[0044] Specifically, the third stress sequence , , ,…, , represents the stress component at the i-th contrast time point, [ , , , , , ] for the stress component S i , the trend vector between the stress component S i-1 at the previous contrast time point and the stress component , = sgn( - ) is calculated, and S i the trend vector between the stress component S i+1 at the next contrast time point and the stress component , = sgn( - ) is calculated, and the sgn function is a sign function for extracting the sign of each stress component. For example, =[100,-20,30,10,-5,15], =[110,-25,30,12,-4,16], - =[10,-5,0,2,1,1], then =[+1,-1,0,+1,+1,+1]. =[105,-30,35,11,-6,17], - =[-5,-5,5,-1,-2,1], then =[-1,-1,+1,-1,-1,+1], by calculating the difference vector Δ = - , Δ =[-2,0,1,-2,-2,0], |Δ |=[2,0,1,2,2,0]. When the component equal to 2 is included in |Δ |, keep ; when the absolute value of each component in |Δ | is less than 2, it means that there is no obvious turning point between and , is a redundant point, and deleting redundant points sequentially rearranging, repeating the above steps in the new sequence until comparing to obtain a fourth stress sequence S 1, S 2, S 3, …, S y， obtaining the stress extreme point sequence according to the fourth stress sequence, wherein the absolute value of at least one component of the difference vector of the trend vectors of two adjacent comparison time points in the fourth stress sequence is equal to 2. In order to distinguish, the time points in the third stress sequence are named as comparison time points.

[0045] In this optional embodiment, the stress extreme point is determined by calculating the sudden change of the change direction of the multi-axis stress component, which can accurately identify the stress extreme point, avoids the uncertainty of artificially setting the coefficient and threshold, and thus improves the accuracy of the extreme point search.

[0046] Optionally, the stress component of the first remaining time point in the fourth stress sequence is equal to the stress component of the first comparison time point in the third stress sequence, the stress component of the last remaining time point in the fourth stress sequence is equal to the stress component of the last comparison time point in the third stress sequence, and the obtaining the stress extreme point sequence according to the fourth stress sequence comprises: deleting the stress component of the first remaining time point in the fourth stress sequence and the stress component of the last remaining time point in the fourth stress sequence to obtain the stress extreme point sequence.

[0047] Specifically, the fourth stress sequence S 1, S 2, S 3,…, S y S 1 is the same as S 1, S 2, S 3, ,… S x S 1 in the third stress sequence S 1, S 2, S 3,…, S y S y S 1, S 2, S 3,…, S x in the third stress sequence​​​​S x the same, fourth stress sequence S 1, S 2, S 3,…, S y in the fourth stress sequence S 1 and S y is the stress component of the redundant remaining time point, in order to construct the stress history into a closed loop connected at both ends for stress analysis, the stress component of the second last analysis time point in the first stress sequence is added at the front end of the first stress sequence, the added “bridge point” and the last analysis time point in the first stress sequence are retained in the fourth stress sequence, and the fourth stress sequence S 1, S 2, S 3,…, S y in the fourth stress sequence S 1 and S y , to obtain the stress extreme point sequence. Wherein, in order to distinguish, the time point in the fourth stress sequence is named as the remaining time point.

[0048] In the optional embodiment, by deleting the stress component of the first remaining time point in the fourth stress sequence and the stress component of the last remaining time point in the fourth stress sequence, the authenticity of the finally output stress extreme point is ensured, thereby improving the accuracy of searching the stress extreme point.

[0049] As shown in Figure 2 , the device 200 for searching the stress extreme point provided by the embodiment of the application comprises: an analysis module 210, configured to perform elastic stress analysis on a pressure vessel subjected to cyclic load to obtain a first stress sequence; an adding module 220, configured to connect the first stress sequence at both ends to form a stress history cycle to obtain a second stress sequence; a first comparison and deletion module 230, configured to delete equal stress components of adjacent comparison time points in the second stress sequence, and retain the stress component of the first comparison time point to obtain a third stress sequence; a second comparison and deletion module 240, configured to obtain a stress extreme point sequence by comparing the stress components in the third stress sequence with trend vectors.

[0050] As shown in Figure 3 , the electronic device 300 provided by the embodiment of the application comprises a memory 310 and a processor 320; the memory 310 is configured to store a computer program; and the processor 320 is configured to implement the method for searching the stress extreme point as described above when the computer program is executed.

[0051] The embodiment of the present application provides a computer readable storage medium, and the computer program is stored on the storage medium. When the computer program is executed by a processor, the method for searching a stress extreme point is realized.

[0052] An electronic device 300 that can be a server or a client of the present application will now be described, which is an example of a hardware device that can be applied to aspects of the present application. The electronic device 300 is intended to represent various forms of digital electronic computing devices such as laptops, desktops, workstations, personal digital assistants, servers, blade servers, mainframes, and other appropriate computing devices. The electronic device 300 can also represent various forms of mobile devices such as personal digital assistants, cellular telephones, smartphones, wearable devices, and other similar computing devices. The components shown here, their connections and relationships, and their functions, are meant to be examples only, and are not meant to limit implementations of the present application described and / or claimed in this document.

[0053] The electronic device 300 includes a computing unit that can perform various appropriate actions and processes in accordance with a computer program stored in a read-only memory (ROM) or a computer program loaded from a storage unit into a random access memory (RAM). In the RAM, various programs and data required for device operation can also be stored. The computing unit, the ROM, and the RAM are connected to each other through a bus. An input / output (I / O) interface is also connected to the bus.

[0054] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing related hardware through a computer program, and the program can be stored in a computer readable storage medium. When the program is executed, the processes of the above-mentioned embodiment methods can be included. The storage medium can be a magnetic disc, an optical disc, a read-only memory (ROM) or a random access memory (RAM), etc. In the present application, the units described as separate components can be or can not be physically separated, and the components shown as units can be or can not be physical units, that is, they can be located in one place or distributed on multiple network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment of the present application. In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0055] Although the present application has been disclosed with reference to the above embodiments, the scope of the present application is not limited to the above. Various changes and modifications can be made to the present application by those skilled in the art without departing from the spirit and scope of the present application, and these changes and modifications should fall within the scope of the present application.

Claims

1. A method for searching stress extrema, characterized in that, include: Elastic stress analysis was performed on a pressure vessel subjected to cyclic loads to obtain the first stress sequence. By connecting the first stress sequence end to end, a stress history cycle is formed to obtain the second stress sequence. Delete the equal stress components at adjacent comparison time points in the second stress sequence, and retain the stress component at the first comparison time point to obtain the third stress sequence; By comparing the trend vectors of the stress components in the third stress sequence, a stress extremum point sequence is obtained.

2. The method for searching stress extrema points according to claim 1, characterized in that, The elastic stress analysis of the pressure vessel subjected to cyclic loads to obtain the first stress sequence includes: The stress components at each analysis time point during the elastic stress analysis of the pressure vessel subjected to cyclic loads are extracted, and the first stress sequence is constructed according to the order of the analysis time points.

3. The method for searching stress extrema points according to claim 1, characterized in that, The cyclic load includes at least one complete load history.

4. The method for searching stress extrema points according to claim 1, characterized in that, The step of connecting the first stress sequence end to end to form a stress history cycle to obtain the second stress sequence includes: The second stress sequence is obtained by adding the stress component of the second-to-last analysis time point in the first stress sequence before the first analysis time point in the first stress sequence.

5. The method for searching stress extrema points according to claim 1, characterized in that, The step of deleting equal stress components at adjacent comparison time points in the second stress sequence and retaining the stress component at the first comparison time point to obtain the third stress sequence includes: Compare the stress components at adjacent comparison time points in the second stress sequence; When the stress component at the first comparison time point in the second stress sequence is equal to the stress component at the second comparison time point, the stress component at the second comparison time point is deleted from the second stress sequence to obtain the third stress sequence. Here, the first comparison time point is the previous comparison time point among adjacent comparison time points, the second comparison time point is the next comparison time point among adjacent comparison time points, and the stress components at adjacent comparison time points in the third stress sequence are not equal.

6. The method for searching stress extrema points according to claim 1, characterized in that, The process of obtaining the stress extremum point sequence by comparing the trend vectors of the stress components in the third stress sequence includes: The first change between the stress component at the first comparison time point and the stress component at the second comparison time point in the third stress sequence is obtained. The sign of the first change is determined using a sign function to obtain a first trend vector. The first comparison time point is adjacent to the second comparison time point, and the first comparison time point is earlier than the second comparison time point. The second change between the stress component at the second comparison time point and the stress component at the third comparison time point is obtained. The sign of the second change is determined using a sign function to obtain a second trend vector. The second comparison time point is adjacent to the third comparison time point, and the second comparison time point is earlier than the third comparison time point. Obtain the difference vector between the first trend vector and the second trend vector; When the absolute value of each component of the difference vector is less than or equal to 1, the stress component at the second comparison time point is deleted from the third stress sequence until the fourth stress sequence is obtained. The stress extreme point sequence is obtained based on the fourth stress sequence.

7. The method for searching stress extrema points according to claim 6, characterized in that, The stress component at the first remaining time point in the fourth stress sequence is equal to the stress component at the first comparison time point in the third stress sequence, and the stress component at the last remaining time point in the fourth stress sequence is equal to the stress component at the last comparison time point in the third stress sequence. Obtaining the stress extreme point sequence based on the fourth stress sequence includes: The stress component at the first remaining time point and the stress component at the last remaining time point in the fourth stress sequence are deleted to obtain the stress extreme point sequence.

8. A device for searching stress extrema, characterized in that, include: The analysis module is used to perform elastic stress analysis on pressure vessels subjected to cyclic loads to obtain the first stress sequence. A module is added to connect the first stress sequence end to end to form a stress history cycle, thereby obtaining a second stress sequence. The first comparison deletion module is used to delete equal stress components at adjacent comparison time points in the second stress sequence, retain the stress component at the first comparison time point, and obtain the third stress sequence. The second comparison and deletion module is used to obtain a stress extreme point sequence by comparing the stress components in the third stress sequence with trend vectors.

9. An electronic device, characterized in that, Including memory and processor; The memory is used to store computer programs; The processor is configured to, when executing the computer program, implement the method for searching stress extrema as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The storage medium stores a computer program that, when executed by a processor, implements the method for searching stress extrema as described in any one of claims 1 to 7.

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