A go-flow-based system failure minimal cut set generation method

Abstract

The application discloses a GO-FLOW-based system failure minimal cut set generation method, realizes common signal identification and renaming processing through GO-FLOW graph traversal search, obtains a minimal path set full set facing system task success, obtains a non-intersected minimal path set full set after deduplication through repeated signal decomposition in the minimal path set full set, obtains a system failure cut set combination according to signal negation and Boolean logic operation in the minimal path set full set, realizes repeated signal reconstruction analysis from bottom to top through binary tree reverse traversal according to the system failure cut set combination, realizes system modular minimal cut set full set generation in combination with inductive merging calculation of each subnode, and further realizes comprehensive analysis expression on the system success minimal path set and the system failure minimal cut set through signal renaming backtracking restoration and signal strength calculation for the modular minimal cut set.

Description

Technical Field

[0001] The present invention belongs to the field of reliability engineering and system safety analysis, and particularly relates to a method for generating a system failure minimum cut set based on GO-FLOW. Background Art

[0002] The GO-FLOW method is a success-oriented system reliability and safety analysis method that can describe the complex dynamic timing operation characteristics of a system under a multi-stage mission profile and simulate the life aging effects and maintenance strategies of equipment. GO-FLOW uses timing signal flows (such as current, water flow, control signal flow, etc.) to describe the potential or actual existence of actual physical quantities or information, and constructs a system dynamic reliability and risk model through the concrete expression of operators and signal lines. The generated GO-FLOW model is similar to a system flow chart, which facilitates model verification and confirmation. At the same time, the GO-FLOW model supports multi-target signal output and can be integrated with online monitoring of system process parameters. It has strong model scalability and generalization capabilities and is currently widely used in nuclear energy, aerospace, transportation, petrochemicals, logistics and other fields.

[0003] However, the prior art found that the existing GO-FLOW method program lacks a qualitative analysis expression of the minimum cut set of system failure (ZYHe, J.Yang, YMHong. A flow-directed minimal path sets method for success path planning and performance analysis. Nuclear Engineering and Technology, 2024, 56(5): 1603-1618.), and instead requires a secondary refinement of the analysis results, which is a cumbersome and error-prone process. Summary of the Invention

[0004] The present application aims at the problems that the existing GO-FLOW method program cannot obtain the system failure minimal cut set and the system minimal cut set full set generation efficiency is low through the state combination method, proposes a system failure minimal cut set generation method based on GO-FLOW, realizes common signal recognition and renaming processing through GO-FLOW graph traversal search, obtains the minimal path set full set for system task success, obtains the non-intersecting minimal path set full set after deduplication through the repeated signal decomposition in the minimal path set full set, obtains the system failure cut set combination according to the signal negation and Boolean logic operation of the minimal path set full set, realizes the reconstruction analysis of the repeated signal from bottom to top through the binary tree reverse traversal according to the system failure cut set combination, realizes the system modular minimal cut set full set generation in combination with the inductive merging calculation of each subnode, and derives the system minimal cut set and its occurrence probability through signal renaming backtracking restoration and signal strength calculation, and then realizes the comprehensive analysis expression of the system success minimal path set and the system failure minimal cut set.

[0005] The first object of the present application is to provide a system minimal path set full set acquisition method based on graph theory traversal search and ideal signal renaming, which can realize system reliability analysis from the perspective of system task success.

[0006] The second object of the present application is to provide a system failure minimal cut set efficient generation method based on minimal path set full set direct conversion, so as to ensure that the GO-FLOW analysis result can be well compatible with the existing failure tree analysis method and probability safety evaluation system.

[0007] The present application is realized at least by one of the following technical solutions.

[0008] A system failure minimal cut set generation method based on GO-FLOW comprises the following steps:

[0009] S1, based on the system GO-FLOW model graph, through graph theory traversal search, common signal recognition and renaming processing are identified, and the minimal path set full set for system task success is obtained;

[0010] S2, according to the repeated signal sorting in the minimal path set full set, the repeated signal in the minimal path set full set is sequentially decomposed from top to bottom through binary tree, and the non-intersecting minimal path set full set after deduplication is obtained;

[0011] S3, based on the non-intersecting minimal path set full set, the signal logic negation operation in the minimal path set full set is sequentially performed, and the system failure cut set combination is obtained through Boolean logic operation;

[0012] S4. Based on the combination of system failure cut sets, reconstruct and analyze the repeated signals through reverse traversal of the binary tree. Combined with the induction and merging of each child node in the binary tree to simplify the calculation, the complete set of system modular minimum cut sets is generated;

[0013] S5. For modular minimum cut sets, the final set of system failure minimum cut sets and their occurrence probability are derived through signal renaming, backtracking and signal strength calculation.

[0014] Furthermore, in step S1, the GO-FLOW model diagram is a direct translation of the reliability logic of the system process structure diagram P&ID diagram. The GO-FLOW model diagram consists of a series of GO-FLOW operators and signal lines. The GO-FLOW operator is used to simulate the failure of equipment functional requirements or operation time-related failures. The GO-FLOW signal line simulates the actual working fluid flow of the system through the signal flow.

[0015] Furthermore, the GO-FLOW model graph traversal search includes the following steps:

[0016] S1.1. Extract the final output signal of the system according to the final signal identification in the GO-FLOW model file for final signal labeling;

[0017] The GO-FLOW model file includes the data structure of the GO-FLOW model diagram, and supports parsing various data information in the GO-FLOW model diagram; the final output signal of the system is an associated embodiment of the system function or state target, and multiple final signals indicate that there are multiple target outputs in the system;

[0018] S1.2. Taking the final output signal of the system as the starting node, reverse the GO-FLOW signal flow to achieve the final signal marking of all signals, and trace the signal flow back to the source signal;

[0019] The nodes refer to network nodes represented by various GO-FLOW operators, and the network nodes are connected to each other through signal lines, i.e., edges between nodes, to form a GO-FLOW model graph;

[0020] S1.3. Based on the final signal marking of the GO-FLOW signal flow, combined with the signal flow branching and merging criteria, the system common signal identification is realized;

[0021] The common signal refers to the output signal of an operator that serves as the input signal of multiple operators at the same time and re-converges at a downstream node. The common signal is used to mark signals that appear multiple times in the entire set of system minimum paths. Due to the influence of the common signal, there is correlation between the minimum paths of the system, and renaming and full probability decomposition are required to obtain correct quantitative analysis results.

[0022] S1.4. Based on the signal flow backtracking analysis, identify the GO-FLOW signal components in each branch flow, and generate the minimum path set through signal renaming processing;

[0023] The complete set of minimum path sets refers to the set of all minimum path sets that ensure the success of the system. The complete set of minimum path sets in GO-FLOW refers to all minimum path set combinations starting from all source signal generators, i.e., GO-FLOW operator No. 25, leading to the final node. During the analysis and calculation process of GO-FLOW, both the path set and the complete set of path sets need to be simplified through Boolean logic to obtain the simplest structural expression.

[0024] Furthermore, the signal renaming process refers to the merging process of one or more ideal signals. Signal renaming is used to simplify the GO-FLOW calculation process and distinguish signals in different states. The renaming rules of GO-FLOW ideal signals include:

[0025] i) Post-rename: Common output signal processing for general function operators; the general function operators are GO-FLOW operators No. 21, 26, 27, 39, 35, 37, and 38, which are used to describe functional requirement failures, runtime-related failures, and maintenance processes of physical components;

[0026] ii) Pre-rename: This renames all input signals of logic operators and special function operators, as well as the input signals of operator 35, whose main input signal has multiple path sets. The logic operators are logic gates including AND, OR, and NOT, while the special function operators are specifically GO-FLOW operators 24, 28, and 40, which implement differential calculation of signal values, signal delay simulation, and multi-stage signal conversion, respectively.

[0027] iii) Process renaming: This is for signal process processing of special function operators and logical NOT gates. The process renaming requires assigning a new number to the signal based on the pre / post renaming process to indicate the signal's differentiation, delay, inversion, or stage interception process. If a second-renamed signal and a first-renamed signal appear simultaneously in the system's minimum path set, they need to be marked and distinguished through the second renaming process.

[0028] Furthermore, in step S2, the repeated signal refers to the same signal appearing multiple times in multiple different system minimum path sets, and the repeated signals are removed by full probability decomposition to obtain the full set of non-intersecting system minimum cut sets and the exact solution of system reliability;

[0029] The repetitive signal removal process based on full probability decomposition includes the following steps:

[0030] 2.1. Sort the repeated signals by their frequency in the system's minimum path set, and extract the signals with the most repetitions from the minimum path set for priority processing.

[0031] 2.2. Treat the repeated signal as a deterministic event Y, and consider two mutually exclusive states: the presence of the repeated signal (i.e., the event occurs) and the absence of the repeated signal (i.e., the event does not occur);

[0032] When a repeated signal exists, it indicates that the device function mode or basic event represented by the signal is successful. At this time, P(Y)=1. The repeated signal is deleted from the system minimum path set to obtain the reduced minimum path set. The reduced path set after deleting the repeated signal is not necessarily the minimum path set. Further simplification through Boolean logic is required to obtain the minimum path set.

[0033] When a duplicate signal does not exist, it indicates that the device function mode or basic event represented by the signal has failed. At this time, if P(Y) = 0, all minimum path sets containing the duplicate signal in the system minimum path set are removed. The minimum path sets removed by negating the duplicate signal can no longer lead to the success of the system task. If a duplicate signal exists in all minimum path sets of the system, the minimum path set of the system after the duplicate signal is deleted will become an empty set, indicating that the system has failed when the duplicate signal does not exist.

[0034] 2.3. Perform similar binary tree recursive decomposition on other repeated signals in turn until all repeated signals have been eliminated, and finally obtain the complete set of non-overlapping minimum path sets after deduplication.

[0035] Furthermore, step S3 includes the following steps:

[0036] 3.1. Based on the complete set of deduplicated disjoint minimal path sets obtained in step S2, extract signals from each disjoint minimal path set in turn, and construct the inverse event of the basic event by logically negating the signal;

[0037] 3.2. By logically negating the sum of each minimum path set in the complete set of disjoint minimum path sets, the sum is converted into a sum-intersection Boolean logic operation between each negated minimum path set, thereby obtaining the combination of system failure cut sets.

[0038] Furthermore, in step S4, the system failure cut set refers to a disjoint minimum cut set without repeated signal expressions obtained by logically inverting the signals in each component minimum path set in the full list of system minimum path sets and performing random combinations; the actual full list of system failure minimum cut sets should be a combination of the system cut set and the repeated signal state decomposition, obtained by reverse traversal of the binary tree.

[0039] Furthermore, the binary tree reverse traversal process includes the following steps:

[0040] 4.1. Based on the combination of system failure cut sets obtained in step S3, the consideration of the success and failure of repeated signals is included again in the reverse order of repeated signal decomposition;

[0041] Furthermore, the left branch represents the failure of the repeated signal, and the minimum modular cut set of the current node is directly obtained by the intersection operation ∩ of the minimum modular cut set of the child node and the repeated signal failure event; on the contrary, the right branch represents the success of the repeated signal, and the minimum modular cut set generated by the child node is directly obtained;

[0042] 4.2. Combine the complete set of minimum cut sets in the left branch node with the complete set of minimum cut sets in the right branch node, and simplify them through Boolean logic to obtain the complete set of minimum modular cut sets of the intermediate nodes in the previous layer.

[0043] 4.3. Through layer-by-layer iterative calculation and merging simplification, the complete set of minimum modular cut sets for top node system failure is finally obtained.

[0044] Furthermore, in step S5, the modular minimum cut set is a combination of failure modes of the combined signal module;

[0045] The combined signal module refers to a signal that renames multiple unnamed signals together during the signal renaming process; the signals in the combined signal module are traced back and restored to identify the specific failure mode of the device, and the minimum cut set is generated through their combination to achieve the final acquisition of the full set of system failure minimum cut sets.

[0046] Furthermore, the modular minimum cut set deconstruction process includes the following steps:

[0047] S5.1. Based on the signal renaming mapping list, trace back and obtain the original signal composition of the combined signal module before renaming, and extract the device function and failure mode corresponding to the original signal;

[0048] S5.2. Based on the original signal composition in the modular minimum cut set, derive the system failure minimum cut set through Boolean logic operations; the minimum cut set is the minimum device failure mode combination for system failure and does not require further simplification;

[0049] S5.3. By analyzing and calculating the signal strength, the occurrence probability of each minimum cut set is obtained, thereby achieving quantitative analysis of the minimum cut set.

[0050] The present invention has the following beneficial effects compared to the prior art:

[0051] 1. The GO-FLOW minimum path set full set acquisition method based on graph theory traversal search provided by the application has the unique advantages of small path set number scale, low calculation complexity, and signal flow (working medium flow) objectified expression, and the analysis efficiency of the algorithm engine can be greatly improved.

[0052] 2. The GO-FLOW minimum cut set generation method based on repeated signal decomposition and reconstruction provided by the application realizes the rapid transformation from the system success minimum path set full set to the system failure minimum cut set full set through the signal inversion logic operation, cutting combination and inductive merging calculation in the minimum path set full set, breaks through the qualitative analysis expression and quantitative calculation of the GO-FLOW method for the system failure minimum cut set, and can promote the good compatibility of the GO-FLOW method with the existing failure tree analysis method and the probability safety evaluation system. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 The system schematic diagram of the embodiment;

[0054] Figure 2 The GO-FLOW model diagram of the embodiment system;

[0055] Figure 3 The repeated signal decomposition diagram of the system minimum path set full set;

[0056] Figure 4 The minimum cut path set transformation principle diagram of the embodiment;

[0057] Figure 5 The binary tree reverse traversal diagram of the embodiment;

[0058] Figure 6 The flowchart of the system failure minimum cut set generation method based on GO-FLOW of the embodiment. DETAILED DESCRIPTION

[0059] In order to make the purpose, technical scheme and advantages of the embodiments of the application clearer, the technical scheme in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application. It should be understood that the described specific embodiments are only used to explain the application, and are not used to limit the application.

[0060] As Figure 6The method for generating a system failure minimum cut set based on GO-FLOW is shown. By decomposing repeated signals in the minimum path set, performing the inversion logic operation of the non-intersecting minimum path set signals, performing the minimum cut set cutting combination, performing the binary tree reverse traversal and merging calculation, and performing the original signal backtracking decomposition, the method finally obtains the system failure minimum cut set. Then, a comprehensive analysis expression of the system success minimum path set and the system failure minimum cut set is established. Specifically, the method includes the following steps:

[0061] S1. Based on the system GO-FLOW model graph, through graph theory traversal search, common signal identification and renaming processing are realized to obtain the complete set of minimum paths for system task success;

[0062] The GO-FLOW model diagram is a direct translation of the reliability logic of the system flow structure diagram (PID diagram). The GO-FLOW model diagram consists of a series of GO-FLOW operators and signal lines. The GO-FLOW operators are used to simulate equipment functional requirement failures or runtime-related failures. The GO-FLOW signal lines simulate the actual working fluid flow of the system through signal flows.

[0063] Furthermore, the GO-FLOW graph traversal search is implemented by the following steps:

[0064] S2.1. Extract the final output signal of the system according to the final signal identification in the GO-FLOW model file for final signal labeling;

[0065] The GO-FLOW model file is a data structure embodiment of the GO-FLOW model diagram. It is a structured data file that supports the analysis of various types of data information in the GO-FLOW model diagram. The system's final output signal is an associated embodiment of the system's function or state goals. Multiple final signals indicate that there are multiple target outputs in the system.

[0066] S2.2. Starting from the final output signal of the system, reverse the GO-FLOW signal flow to achieve the final signal marking of all signals. The signal flow is traced back to the source signal (GO-FLOW operator No. 25).

[0067] The nodes refer to network nodes abstracted from various GO-FLOW operators, which are connected to each other through signal lines (edges between nodes) to form a GO-FLOW model graph; in order to facilitate the effective identification of GO-FLOW operators, the GO-FLOW operator encoding is consistent with the GO-FLOW signal flow encoding.

[0068] S2.3. Based on the final signal marking of the GO-FLOW signal flow, combined with the signal flow branching and merging criteria, the system common signal identification is realized;

[0069] The shared signal refers to the output signal of an operator that simultaneously serves as the input signal of multiple operators and rejoins at a downstream node. The shared signal is used to mark signals that appear multiple times in the entire set of system minimum paths. Due to the influence of the shared signal, there are correlations between the system minimum paths, requiring renaming and full probability decomposition to obtain accurate quantitative analysis results.

[0070] S2.4. Based on the signal flow backtracking analysis, identify the GO-FLOW signal components in each branch flow, and generate the minimum path set through signal renaming processing;

[0071] The signal renaming process is the process of merging one or more ideal signals. Signal renaming can be used to simplify the GO-FLOW calculation process and distinguish signals in different states. The GO-FLOW ideal signal renaming rules include:

[0072] i) Post-rename: Common output signal processing for general function operators. The general function operators are GO-FLOW operators 21, 26, 27, 39, 35, 37, and 38, which are generally used to describe functional requirement failures, runtime-related failures, and maintenance processes of physical components.

[0073] ii) Pre-rename: This renames all input signals to logic operators and special function operators, as well as the input signals of operator #35, whose main input signal has multiple paths. Logic operators include logic gates such as "AND," "OR," and "NOT," while special function operators specifically include GO-FLOW operators #24, #28, and #40, which implement differential calculation of signal values, signal delay simulation, and multi-stage signal conversion, respectively.

[0074] iii) Process renaming: This involves signal processing for special function operators and logical NOT gates. This process renaming involves assigning a new number to the signal, based on the pre / post renaming process, to indicate the signal's differentiation, delay, inversion, or stage interception. Because the secondarily renamed signal is highly correlated with the first-named signal and may appear simultaneously in the system's complete set of minimal paths, the second renaming process is necessary to distinguish them.

[0075] The complete set of minimal paths refers to the set of all minimal paths that ensure system success. In GO-FLOW, the complete set of minimal paths refers to all combinations of minimal paths from all source signal generators (GO-FLOW operator #25) to the final node. During GO-FLOW analysis and calculation, both the path set and the complete set of paths must be simplified using Boolean logic to obtain the simplest structural expression.

[0076] S2. Sorting the repeated signals in the minimum path set, performing binary tree decomposition on the repeated signals in the minimum path set from top to bottom, and obtaining the non-overlapping minimum path set after deduplication;

[0077] A repetitive signal refers to the same signal appearing multiple times in multiple different system minimum path sets. Due to the correlation of repetitive signals, the complete set of system minimum path sets cannot be directly calculated. Repetitive signals must first be removed through full probability decomposition to obtain the complete set of disjoint system minimum cut sets and the exact solution for system reliability.

[0078] Furthermore, the repeated signal removal process based on full probability decomposition is specifically implemented by the following steps:

[0079] 3.1. Sort the repeated signals by their frequency in the system's minimum path set, and extract the signals with the most repetitions from the minimum path set for priority processing.

[0080] 3.2. Treat the repeated signal as a deterministic event (event Y), considering two mutually exclusive states: the presence of the repeated signal (event occurs) and the absence of the repeated signal (event does not occur);

[0081] according to Figure 6 As shown in step 1, MPS represents the complete set of minimum path sets in the system, MPS Sn Represents the minimum path set contained in the signal flow Sn, S 1 =0 and S 1 =1 respectively indicates the failure (non-existence) and success (existence) branches of the duplicate signal (#1) to be decomposed. S1 MPS S1 =MPS S2 ∪(S 1 ∩MPS S2 ) represents the parent node MPS S1 Decomposition into MPS via binary tree S2 and MPS S5 , because the left leaf node indicates that the repeated signal fails, and the right leaf node indicates that the repeated signal succeeds, so S 1 =1 to connect with the right leaf node MPS S5 Similarly, the subsequent leaf nodes are decomposed into the minimum path set MPS of the irredecomposable system through binary tree decomposition and Boolean logic simplification. S3 、MPS S4 、MPS S6 、MPS S7 .

[0082] When a repeated signal exists, it indicates that the device function mode or basic event represented by the signal is successful. At this time, P(Y) = 1. The repeated signal can be deleted from the system's minimum path set to obtain the reduced minimum path set. It is worth noting that the reduced path set (deleting repeated signals) is not necessarily the minimum path set. Further simplification through Boolean logic is required to obtain the minimum path set.

[0083] If a duplicate signal does not exist, the device function mode or basic event represented by the signal has failed. At this point, if P(Y) = 0, all minimum path sets containing the duplicate signal are removed from the system's minimum path set set. The removed minimum path sets (after negating the duplicate signal) are no longer able to lead to successful system tasks. If a duplicate signal exists in all system minimum path sets, the system's minimum path set set after the duplicate signal is removed becomes an empty set, indicating that the system has failed when the duplicate signal does not exist.

[0084] 3.3. Perform similar binary tree recursive decomposition on other repeated signals in turn until all repeated signals have been eliminated, and finally obtain the complete set of non-intersecting minimum path sets after deduplication.

[0085] S3. Based on the complete set of disjoint minimum path sets, logically negate the signals in the complete set of minimum path sets in sequence, and obtain a system failure cut set combination through Boolean logic operations. The minimum cut set conversion process is implemented by the following steps:

[0086] 4.1. Based on the complete set of deduplicated disjoint minimal path sets obtained in step S2, extract signals from each disjoint minimal path set in turn, and construct the inverse event of the basic event by logically negating the signal;

[0087] 4.2. By logically negating the sum of each minimum path set in the complete set of disjoint minimum path sets, the sum is converted into a "sum-to-intersection" Boolean logic operation between each negated minimum path set, thereby obtaining a combination of system failure cut sets;

[0088] S4. Based on the combination of system failure cut sets, the reconstructed analysis of repeated signals is realized through reverse traversal of the binary tree. The calculation is simplified by combining the induction and merging of each child node in the binary tree to generate the complete set of system modular minimum cut sets.

[0089] In step S4, the system failure cut set is a disjoint minimum cut set containing no duplicate signal representations, obtained by logically inverting the signals in each component minimum path set in the full list of system minimum path sets and performing random combinations. The actual full list of system failure minimum cut sets should be a combination of the system cut set and the decomposition of duplicate signal states, and can be obtained by reverse traversing the binary tree.

[0090] according to Figure 6 As shown in step 4, MCSs represents the complete set of system minimum cut sets, S 2 =0 and S 2 =1 indicates the failure (non-existence) and success (existence) branches of the repeated signal (#2) to be decomposed. System Minimum Cut Set MCS s3、 MCS s4、 MCS s6、 MCS s7 The system minimum path set MPS s3、 MPS s4、 MPS s6、 MPS s7 Obtained by logical inversion. MCS S2 =(MCS S3 ∩S 2 )∪MCS S4 It represents the minimum cut set MCS of the left leaf node of the system failure S3 After taking the intersection with the repeated signal #2, the system successfully completes the minimum cut set MCS of the right leaf node. S4 The system cut set obtained after taking the union may not be the minimum cut set. It is necessary to use Boolean logic simplification to obtain the system minimum cut set MCS S2 Similarly, the system minimum cut set MCS can be obtained by reverse traversal of the binary tree and Boolean logic simplification. S .

[0091] Furthermore, the binary tree reverse traversal process is implemented by the following steps:

[0092] 5.1. Based on the complete set of system cuts obtained in step S3, the consideration of the success and failure of repeated signals is included again in the reverse order of repeated signal decomposition;

[0093] Furthermore, the left branch represents the failure of the repeated signal, and the minimum modular cut set of the current node can be directly obtained by the intersection operation (∩) of the minimum modular cut set of the child node and the repeated signal failure event; on the contrary, the right branch represents the success of the repeated signal, and the minimum modular cut set generated by the child node can be directly obtained;

[0094] 5.2. Combine the complete set of minimal cut sets in the left branch node with the complete set of minimal cut sets in the right branch node (∪), and use Boolean logic simplification to obtain the complete set of minimal modular cut sets of the intermediate nodes in the previous layer;

[0095] 5.3. Through layer-by-layer iterative calculation and merging simplification, the complete set of minimum modular cut sets for top node system failure is finally obtained.

[0096] S5. For modular minimum cut sets, derive the final set of system failure minimum cut sets and their occurrence probabilities through signal renaming, backtracking, and signal strength calculation. The modular minimum cut set is a combination of failure modes of the combined signal modules.

[0097] Furthermore, the combined signal module refers to the signal renaming process that combines multiple unnamed signals (such as the output signals of multiple GO-FLOW operators in a cascaded structure) to simplify calculations. To ultimately obtain the complete set of minimal cut sets for system failures, it is necessary to further back-restore the signals in the combined signal module, identify the specific failure modes of the given equipment, and generate the minimal cut set through their combination.

[0098] Furthermore, the modular minimum cut set deconstruction process is implemented by the following steps:

[0099] S6.1. Based on the signal renaming mapping list, trace back and obtain the original signal composition of the combined signal module before renaming, and extract the device function and failure mode corresponding to the original signal;

[0100] S6.2. Based on the original signal composition in the modular minimum cut set, derive the system failure minimum cut set through Boolean logic operations; the minimum cut set is the minimum device failure mode combination for system failure and does not require further simplification;

[0101] S6.3. By analyzing and calculating the signal strength, the occurrence probability of each minimum cut set is obtained, thereby achieving quantitative analysis of the minimum cut set.

[0102] The system minimum cut set consists of the minimum combination of equipment failure modes that causes system failure. By reading the characteristic parameters of the GO-FLOW operator, the reliability parameters of the system equipment can be obtained, including the success probability and failure probability. The occurrence probability of each minimum cut set is equal to the cumulative failure probability of the equipment included in the cut set.

[0103] As a specific embodiment, this embodiment takes a hypothetical water supply system as an example to illustrate the relevant method proposed by the present invention. Figure 1 As shown in Figure 1, the system in this embodiment consists of a water supply storage tank (CCST), three water supply pumps (MDP-a, MDP-b, and TDP), four electric valves (MOV-1 through MOV-4), and several check valves (CV-0 through CV-4). The water supply system supplies water to users through four pipelines. For the system to operate normally, at least one pipeline must be operational.

[0104] Step 1: Obtain the complete set of system minimum paths

[0105] Refer to the system flow chart and establish the system GO-FLOW model as follows Figure 2 As shown in Figure 2, the GO-FLOW model uses operator 25 to represent the integrity of equipment such as the water source in the storage tank, the storage tank, and the check valves (CV-0 to CV-4), which are represented by operator 21. Assuming that the water supply system is not put into operation under normal circumstances and is only put into use in emergencies, the water supply system can be considered as a standby state, and the water supply pump and electric valve can be simulated in a normally closed state using operator 26. Considering the relatively low reliability of the water pump and its failure over time, it is simulated in the model using operator 35. The final system signal is 20. Through graph theory traversal search, the complete set of the system's minimum path set is obtained, see Table 1. The signal renaming, restoration and tracing records during the process of obtaining the complete set of the system's minimum path set are shown in Table 2. The success rate and failure rate of each equipment component are shown in Table 6.

[0106] Table 1 The complete set of system minimum paths

[0107]

[0108] Table 2 Signal renaming and restoration traceback records

[0109] Original signal Rename signal 1,2,3 24 5，8 25 11 26 4,7,10 27 6,9,13 28 12 29 19 30 18 31 17 32 16 33

[0110] Step 2: Minimum path set full set repeated signal decomposition

[0111] According to the analysis results in Table 1, the system's final output signal #20 contains the following 8 minimum path sets: {[24,28,30], [24,25,29,30], [24,28,31], [24,25,29,31], [24,25,26,32], [24,27,32], [24,25,26,33], [24,27,33]}.

[0112] The system minimum path set full set repeated signal decomposition process see Figure 3 and Figure 6According to the above minimum path set (AR1), #24 is the most frequently occurring repeated signal (repeated 8 times). According to the total probability decomposition theory, considering the two cases of signal #24's presence and absence, the minimum path set is decomposed into the left node AR3 and the right node AR2. The right branch node indicates that the repeated signal #24 exists (that is, the event represented by it successfully occurs). In this case, the repeated signal #24 can be deleted from all minimum path sets. Therefore, the minimum path set of the right branch node AR2 becomes {[28,30], [25,29,30], [28,31], [25,29,31], [25,26,32], [27,32], [25,26,33], [27,33]}. The left branch node indicates that the repeated signal #24 does not exist (that is, the event represented by it fails to occur). As a result, all minimum path sets containing the repeated signal #24 are eliminated, and the left branch node AR3 becomes an empty set.

[0113] Furthermore, by identifying repeated signals in the minimum path set in AR2, we find that signal #25 has the most repetitions (repeating 4 times). Similarly, based on the presence or absence of signal #25, AR2 is decomposed into two branches, AR4 and AR5. The minimum path set for the right node AR4 is: {[28,30], [29,30], [28,31], [29,31], [26,32], [27,32], [26,33], [27,33]}, and the minimum path set for the left node AR5 is: {[28,30], [28,31], [27,32], [27,33]}. Traversing downward sequentially, if a path set in a node is contained in another path set, we first need to perform Boolean logic simplification to absorb the contained path set, thereby obtaining the minimum path set for that node. The complete set of minimum path sets of sub-nodes at all levels obtained in the repeated signal decomposition process is shown in Table 3.

[0114] Table 3 The complete set of minimum path sets of sub-nodes at all levels obtained during repeated signal decomposition

[0115]

[0116]

[0117] Step 3: Minimum Cut Set Conversion

[0118] After decomposing all duplicate signals in the minimum path set of the system, all decomposed branch nodes will no longer contain duplicate signals. At this time, a device failure can be selected from the minimum path set of each leaf node after decomposition (logical inversion). These device failure combinations will form a cut set. For the principle of combined cutting, see Figure 4 . Figure 4In the example, MPS#1 and MPS#2 represent the first and second minimum paths in the system's minimum path set, respectively. If the system's minimum path set contains N minimum paths, then MPS#N represents the Nth minimum path in the system's minimum path set. Similarly, MCS#1 represents the first minimum cut set in the system's minimum cut sets. If the system's minimum cut sets contain M minimum device failure mode combinations that lead to system failure, then MCS#M represents the Mth minimum cut set in the system's minimum cut sets.

[0119] For example, the node AR26 whose original minimum path set is {

[30] ,

[31] ,

[32] ,

[33] } is obtained by inverting the cut set: The original minimum path set is an empty set The cut set obtained by negating the node AR19 is the complete set U. By traversing all possible failure combinations, the complete set of minimal cut sets for the reduced system failure after decomposition is obtained. If the complete set of minimal path sets for the decomposed system is empty, it means that there is no successful path set in the system after the repeated signal decomposition, resulting in system failure, and the system's minimal cut set is also empty.

[0120] Step 4: Obtain the complete set of system minimum modular cut sets

[0121] The conversion obtained in step 3 above is the complete set of simplified minimum cut sets without repeated signal expressions. However, the complete set of actual system failure minimum cut sets is a combination of repeated signals and the complete set of simplified minimum cut sets after deduplication. It is necessary to perform a reverse traversal of the binary tree (bottom-up inductive analysis) based on the complete set of simplified minimum cut sets after deduplication and combined with the decomposition of repeated signal states. For the reverse traversal process of the binary tree, see Figure 5 During the reverse traversal of the binary tree, the intersection of the minimum cut set subset recorded in the left node and the repeated signal failure is taken, and then merged and simplified with the minimum cut set subset in the right node (coupled with the repeated signal failure). Finally, the minimum cut sets of all leaf nodes are aggregated to the top node to obtain the complete minimum cut set of the system.

[0122] As a specific embodiment, the reverse traversal of the binary tree is performed starting from leaf nodes AR22 and AR23. The cut set of leaf node AR22 is The cut set of leaf node AR23 is Failure with repeated signals After taking the intersection Then Added to node AR21, the cut set of node AR21 is Similarly, disable the cut set and repeated signal of AR21 After taking the intersection Cut set with AR20 Add to node AR14, and obtain the cut set of AR14 as At this point, the cut set of AR14 is not the minimum cut set. It is necessary to simplify the minimum modular cut set of AR14 through Boolean logic: This iterates upwards layer by layer, and finally the minimum cut sets of all leaf nodes are gathered to the top node AR1, and the minimum modular cut set of the system can be obtained as The complete set of minimum modular cut sets of each child node during the reverse traversal of the binary tree is shown in Table 4.

[0123] Table 4 Minimum modular cut sets for each node in binary tree traversal

[0124]

[0125]

[0126] Step 5: Generate the complete set of system failure minimum cut sets

[0127] Based on the signal composition of the system's minimum cut set and the signal renaming and restoration traceability record list (see Table 2), the minimum device failure mode combination in the minimum cut set is obtained, as shown in Table 5. The system device success and failure probability parameters used to calculate the minimum cut set occurrence probability are shown in Table 6.

[0128] Table 5. Complete set of minimum cut sets for system failure

[0129]

[0130]

[0131]

[0132] Table 6 System equipment success probability and failure probability

[0133] Signal number Device Name Success rate Failure rate 2 CCST 0.999998 0.000002 3 CV-0 0.999996 0.000004 10 CV-1 0.999996 0.000004 11 CV-2 0.999996 0.000004 12 CV-3 0.999996 0.000004 13 CV-4 0.999996 0.000004 4 MDP-a 0.99835 0.00165 6 MDP-b 0.99835 0.00165 5 TDP 0.9685 0.0315 16 MOV-1 0.9957 0.0043 17 MOV-2 0.9957 0.0043 18 MOV-3 0.9957 0.0043 19 MOV-4 0.9957 0.0043

[0134] The minimum cut sets of the system equipment reliability parameters are finally obtained, which are 19, namely: {[CCST failure], [CV-0 failure], [MDP-b failure, MDP-a failure, TDP failure], [MDP-b failure, CV-1 failure, TDP failure], [CV-4 failure, MDP-a failure, TDP failure], [CV-4 failure, CV-1 failure, TDP failure], [MOV-4 failure, MOV-3 failure, MDP-a failure, TDP failure], [MOV-4 failure, MOV-3 failure, CV-1 failure, TDP failure], [MOV-2 ​​failure, MOV-1 failure, MDP-b failure, TDP failure], [MOV-2 ​​failure, MOV-1 failure, CV-4 failure, TDP failure], [CV-3 failure, MDP- -b failure, MOV-1 failure, MOV-2 ​​failure], [CV-3 failure, CV-4 failure, MOV-1 failure, MOV-2 ​​failure], [MOV-4 failure, MOV-3 failure, MOV-1 failure, MOV-2 ​​failure], [CV-2 failure, MDP-a failure, CV-3 failure, MDP-b failure], [CV-2 failure, MDP-a failure, CV-3 failure, CV-4 failure], [CV-2 failure, CV-1 failure, MDP-b failure, CV-3 failure], [CV-1 failure, CV-2 failure, CV-3 failure, CV-4 failure], [MOV-4 failure, MOV-3 failure, CV-2 failure, MDP-a failure], [MOV-4 failure, MOV-3 failure, CV-2 failure, CV-1 failure]}.

[0135] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, numerous modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can better understand and utilize the present invention.

Claims

1. A method for generating a minimum cut set of system failure based on GO-FLOW, characterized in that: The following steps are involved: S1. Based on the system GO-FLOW model graph, through graph theory traversal search, common signal identification and renaming processing are realized to obtain the complete set of minimum paths for system task success; S2. Sorting the repeated signals in the minimum path set, performing binary tree decomposition on the repeated signals in the minimum path set from top to bottom, and obtaining the non-overlapping minimum path set after deduplication; S3. Based on the complete set of disjoint minimum path sets, logically negate the signals in the complete set of minimum path sets in turn, and obtain the system failure cut set combination through Boolean logic operations; S4. Based on the combination of system failure cut sets, reconstruct and analyze the repeated signals through reverse traversal of the binary tree. Combined with the induction and merging of each child node in the binary tree to simplify the calculation, the complete set of system modular minimum cut sets is generated; The system failure cut set refers to a disjoint minimum cut set without repeated signal expressions obtained by logically inverting the signals in each component minimum path set in the full list of system minimum path sets and performing random combinations. The actual full list of system failure minimum cut sets should be a combination of the system cut set and the decomposition of the repeated signal state, obtained by reverse traversal of the binary tree. S5. For modular minimum cut sets, the final set of system failure minimum cut sets and their occurrence probability are derived through signal renaming, backtracking and signal strength calculation.

2. The method for generating a system failure minimum cut set based on GO-FLOW according to claim 1, characterized in that: In step S1, the GO-FLOW model diagram is a direct translation of the reliability logic of the system flow structure diagram P&ID diagram. The GO-FLOW model diagram consists of a series of GO-FLOW operators and signal lines. The GO-FLOW operators are used to simulate equipment functional requirement failures or runtime-related failures. The GO-FLOW signal lines simulate the actual working fluid flow of the system through signal flows.

3. The method for generating a system failure minimum cut set based on GO-FLOW according to claim 1, characterized in that: The GO-FLOW model graph traversal search includes the following steps: S1.

1. Extract the final output signal of the system according to the final signal identification in the GO-FLOW model file for final signal labeling; The GO-FLOW model file includes the data structure of the GO-FLOW model diagram, and supports parsing various data information in the GO-FLOW model diagram; the final output signal of the system is an associated embodiment of the system function or state target, and multiple final signals indicate that there are multiple target outputs in the system; S1.

2. Taking the final output signal of the system as the starting node, reverse the GO-FLOW signal flow to achieve the final signal marking of all signals, and trace the signal flow back to the source signal; Node refers to the network node represented by each GO-FLOW operator. The network nodes are connected to each other through signal lines, i.e., edges between nodes, forming a GO-FLOW model graph. S1.

3. Based on the final signal marking of the GO-FLOW signal flow, combined with the signal flow branching and merging criteria, the system common signal identification is realized; The common signal refers to the output signal of an operator that serves as the input signal of multiple operators at the same time and re-converges at a downstream node. The common signal is used to mark signals that appear multiple times in the entire set of system minimum paths. Due to the influence of the common signal, there is correlation between the minimum paths of the system, and renaming and full probability decomposition are required to obtain correct quantitative analysis results. S1.

4. Based on the signal flow backtracking analysis, identify the GO-FLOW signal components in each branch flow, and generate the minimum path set through signal renaming processing; The complete set of minimum path sets refers to the set of all minimum path sets that ensure the success of the system. The complete set of minimum path sets in GO-FLOW refers to all minimum path set combinations starting from all source signal generators, i.e., GO-FLOW operator No. 25, leading to the final node. During the analysis and calculation process of GO-FLOW, both the path set and the complete set of path sets need to be simplified through Boolean logic to obtain the simplest structural expression.

4. The method for generating a system failure minimum cut set based on GO-FLOW according to claim 3, characterized in that: The signal renaming process refers to the merging of one or more ideal signals. Signal renaming is used to simplify the GO-FLOW calculation process and distinguish signals in different states. The GO-FLOW ideal signal renaming rules include: i) Post-rename: Common output signal processing for general function operators; the general function operators are GO-FLOW operators No. 21, 26, 27, 39, 35, 37, and 38, which are used to describe functional requirement failures, runtime-related failures, and maintenance processes of physical components; ii) Pre-rename: This renames all input signals of logic operators and special function operators, as well as the input signals of operator 35, whose main input signal has multiple path sets. The logic operators are logic gates including AND, OR, and NOT, while the special function operators are specifically GO-FLOW operators 24, 28, and 40, which implement differential calculation of signal values, signal delay simulation, and multi-stage signal conversion, respectively. iii) Process renaming: This is for signal process processing of special function operators and logical NOT gates. The process renaming requires assigning a new number to the signal based on the pre / post renaming process to indicate the signal's differentiation, delay, inversion, or stage interception process. If a second-renamed signal and a first-renamed signal appear simultaneously in the system's minimum path set, they need to be marked and distinguished through the second renaming process.

5. The method for generating a system failure minimum cut set based on GO-FLOW according to claim 1, characterized in that: In step S2, the repeated signal refers to the same signal appearing multiple times in multiple different system minimum path sets. The repeated signals are removed by full probability decomposition to obtain the complete set of non-intersecting system minimum cut sets and the exact solution of system reliability; The repetitive signal removal process based on full probability decomposition includes the following steps: 2.

1. Sort the repeated signals by their frequency in the system's minimum path set, and extract the signals with the most repetitions from the minimum path set for priority processing. 2.

2. Treat the repeated signal as a deterministic event Y, considering two mutually exclusive states: the presence of the repeated signal (i.e., the event occurs) and the absence of the repeated signal (i.e., the event does not occur); When a repeated signal exists, it indicates that the device function mode or basic event represented by the signal is successful. At this time, P(Y)=1. The repeated signal is deleted from the system minimum path set to obtain the reduced minimum path set. The reduced path set after deleting the repeated signal is not necessarily the minimum path set. Further simplification through Boolean logic is required to obtain the minimum path set. When a duplicate signal does not exist, it indicates that the device function mode or basic event represented by the signal has failed. At this time, if P(Y) = 0, all minimum path sets containing the duplicate signal in the system minimum path set are removed. The minimum path sets removed by negating the duplicate signal can no longer lead to the success of the system task. If a duplicate signal exists in all minimum path sets of the system, the minimum path set of the system after the duplicate signal is deleted will become an empty set, indicating that the system has failed when the duplicate signal does not exist. 2.

3. Perform similar binary tree recursive decomposition on other repeated signals in turn until all repeated signals have been eliminated, and finally obtain the complete set of non-overlapping minimum path sets after deduplication.

6. The method for generating a system failure minimum cut set based on GO-FLOW according to claim 1, characterized in that: Step S3 includes the following steps: 3.

1. Based on the complete set of deduplicated disjoint minimal path sets obtained in step S2, extract signals from each disjoint minimal path set in turn, and construct the inverse event of the basic event by logically negating the signal; 3.

2. By logically negating the sum of each minimum path set in the complete set of disjoint minimum path sets, the sum is converted into a sum-intersection Boolean logic operation between each negated minimum path set, thereby obtaining the combination of system failure cut sets.

7. The method for generating a system failure minimum cut set based on GO-FLOW according to claim 1, characterized in that: The binary tree reverse traversal process, The following steps are involved: 4.

1. Based on the combination of system failure cut sets obtained in step S3, the consideration of the success and failure of repeated signals is included again in the reverse order of repeated signal decomposition; The left branch represents the failure of repeated signals. The minimum modular cut set of the current node is obtained directly through the intersection operation ∩ of the minimum modular cut set of the child node and the repeated signal failure event; In contrast, the right branch represents the success of the repeated signal, and directly obtains the full set of minimum modular cut sets generated by the child nodes; 4.

2. Combine the complete set of minimum cut sets in the left branch node with the complete set of minimum cut sets in the right branch node, and simplify them through Boolean logic to obtain the complete set of minimum modular cut sets of the intermediate nodes in the previous layer. 4.

3. Through layer-by-layer iterative calculation and merging simplification, the complete set of minimum modular cut sets for top node system failure is finally obtained.

8. The method for generating a system failure minimum cut set based on GO-FLOW according to any one of claims 1 to 7, characterized in that: In step S5, the modular minimum cut set is a combination of failure modes of the combined signal module; The combined signal module refers to a signal that renames multiple unnamed signals together during the signal renaming process; the signals in the combined signal module are traced back and restored to identify the specific failure mode of the device, and the minimum cut set is generated through their combination to achieve the final acquisition of the full set of system failure minimum cut sets.

9. The method for generating a system failure minimum cut set based on GO-FLOW according to claim 8, characterized in that: The modular minimum cut set deconstruction process includes the following steps: S5.

1. Based on the signal renaming mapping list, trace back and obtain the original signal composition of the combined signal module before renaming, and extract the device function and failure mode corresponding to the original signal; S5.

2. Based on the original signal composition in the modular minimum cut set, derive the system failure minimum cut set through Boolean logic operations; the minimum cut set is the minimum device failure mode combination for system failure and does not require further simplification; S5.

3. By analyzing and calculating the signal strength, the occurrence probability of each minimum cut set is obtained, thereby achieving quantitative analysis of the minimum cut set.

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