Risk assessment method of quay crane failure mode based on fuzzy grey correlation

Abstract

The present invention relates to the technical field of port terminal hoisting equipment, and provides a quay crane failure mode risk assessment method based on fuzzy grey correlation. The method comprises the following steps: establishing a quay crane failure mode assessment team, determining the failure mode, and the fuzzy comment set and fuzzy weight set of the risk factor; aggregating the evaluation information of the risk factor and determining the subjective weight; defuzzifying the aggregated risk factor fuzzy information into a clear value; establishing a normalized matrix of the risk factor information; defuzzifying and normalizing the subjective weight; determining the grey correlation coefficient of the quay crane failure mode to the reference sequence based on the risk factor normalized matrix; calculating the objective weight of the risk factor using the entropy weight method; determining the combined weight based on the improved game theory combined weighting method; determining the risk priority sequence of the quay crane failure mode according to the grey correlation degree, and determining the risk sequence of the quay crane failure mode. The method has guiding significance for the risk assessment of the quay crane failure mode.

Description

Technical Field

[0001] The invention relates to the technical field of port terminal lifting equipment, and in particular to a quay crane failure mode risk assessment method based on fuzzy grey correlation. Background Art

[0002] With the emergence of large container ships, shore container cranes (quay cranes) are gradually developing towards heavy-duty, professional and green directions, while also putting forward higher requirements for the safety management of quay cranes.

[0003] Studying the failure mode risk decision-making method of the quay crane working mechanism and metal structure is of great significance to ensuring the safe production, maintenance and management of the quay crane, as well as improving the economic benefits of the port terminal.

[0004] The paper "Research on Health Monitoring Technology of Shore Container Cranes Based on FMEA" ([J] Hoisting and Conveying Machinery. 2019(10)) applies the traditional failure mode and effects analysis (FMEA) method to the risk analysis of the metal structure and lifting mechanism of shore container cranes. However, the traditional FMEA has some shortcomings, such as: using definite numerical values ​​to describe risk assessment factors and not considering the weight of risk factors.

[0005] The paper “Failure Mode and Impact Analysis of Quay Crane Heightening Construction Process Based on Fuzzy Set Theory” ([J] Journal of China Construction Machinery. 2018(1)) uses fuzzy set theory to describe expert knowledge and experience, and tries to eliminate the influence of subjective factors on the results when different experts evaluate. However, this method determines the risk priority according to the risk priority RPN, and does not consider the weight of risk factors. Summary of the invention

[0006] In view of the shortcomings of the existing decision-making methods for failure modes of quay cranes, the present invention provides a failure mode assessment method for quay cranes based on fuzzy grey correlation, which solves the problem of combining weights of different risk factors such as occurrence (O), severity (S) and detection (D), taking into account the advantages of both subjective weights and objective weights. Considering the fuzziness of experts' evaluation of risk factors, the grey correlation analysis method is used to rank the risk of quay crane risk modes, improve the ability to process fuzzy and uncertain information, improve the accuracy of risk assessment of quay crane failure modes, and ensure the safe production of quay cranes.

[0007] In order to solve the problems of the prior art, the technical solution adopted by the present invention is:

[0008] The quay crane failure mode risk assessment method based on fuzzy grey correlation includes the following steps:

[0009] Step 1: Establish a quay crane risk model assessment team to determine the risk model, as well as the fuzzy comment set and fuzzy weight set of risk factors, where the elements in the fuzzy comment set are trapezoidal fuzzy numbers, and the elements in the fuzzy weight set are trapezoidal fuzzy numbers. The members of the assessment team are no less than three people.

[0010] Step 2: Aggregate the evaluation information of the risk factors by the assessment team and determine the subjective weight of the risk factors;

[0011] Step 3, defuzzification of the trapezoidal fuzzy numbers in the fuzzy comment set of the risk factors;

[0012] Step 4: normalize the clear values ​​obtained in step 3 to obtain the matrix R = (r ij ),

[0013] Among them, the normalized formula for the larger the better risk factor is as follows

[0014]

[0015] The “bigger is better” risk factor is a benefit-type risk factor. The larger the value after defuzzification, the smaller the risk and the safer the system.

[0016] Among them, the normalized formula for the smaller the better risk factor is as follows

[0017]

[0018] The “smaller the better” risk factor is a cost-type risk factor. The smaller the value after defuzzification, the smaller the risk and the safer the system.

[0019] Step 5, defuzzify the trapezoidal fuzzy number of the subjective weight, and the processing method is the same as step 3;

[0020] Step 6, normalizing the clear value after the defuzzification process in step 5;

[0021] Step 7: Based on the risk factor matrix R, the following grey correlation coefficient matrix is ​​calculated as follows:

[0022] ξ=(ξ ij ) M×N ;

[0023] Step 8, calculating the objective weight of the risk factor based on the grey correlation coefficient matrix;

[0024] Step 9: Based on the improved game theory combined weighting method, determine the combined weight vector of risk factors:

[0025] In the formula

[0026] Step 10: Calculate the grey correlation degree of the failure mode of the quay crane. The formula is as follows:

[0027] B=w 1×j ×(ξ ij ) T =(b1, b2, ..., b i ,…,b M ),

[0028] Arrange the elements in vector B in descending order to obtain the risk ranking result of quay crane failure mode. The smaller the grey correlation degree, the greater the risk.

[0029] As an improvement, the risk factors in step 1 are occurrence (O), severity (S) and detection (D), and the fuzzy weights of the risk factors are concentrated in trapezoidal fuzzy numbers as follows:

[0030] w j =(w j(1) , w j(2) , w j(3) , w j(4) ).

[0031] As an improvement, the calculation method of the subjective weight in step 2 is as follows: Assuming there are K experts, the number of risk failure modes is M, the number of risk factors is N, each expert evaluates all failure modes according to the comment set, and obtains the matrix E (k) for

[0032] E (k) =[e (k) ij ] M×N

[0033] The element e in the matrix (k) ij is the trapezoidal fuzzy number of the risk factor, expressed as

[0034]

[0035] The aggregation function formula for aggregating K expert evaluation information is:

[0036] Agg(e ij )=Agg(e (1) ij , e (2) ij ,…,e (k) ij ),

[0037] Among them, Agg(.) is an aggregation function, and

[0038]

[0039]

[0040]

[0041]

[0042] As an improvement, the trapezoidal fuzzy number defuzzification formula of the risk factor in step 3 is:

[0043]

[0044] As an improvement, the explicit value obtained in step 6 is normalized, and the formula is

[0045]

[0046] As an improvement, the calculation formula of the grey correlation coefficient in the grey correlation coefficient matrix in step 7 is as follows

[0047]

[0048] In the formula, the grey relational resolution coefficient ζ is taken as 0.5, ξ oj is the reference value.

[0049] As an improvement, the calculation steps of the objective weight of the risk factor in step 8 are as follows:

[0050] Step 8.1, calculate the ratio of the grey correlation coefficient of the i-th risk failure mode under the j-th risk factor:

[0051]

[0052] Step 8.2, calculate the entropy of the j-th risk factor

[0053]

[0054] Step 8.3, calculate the entropy weight of the j-th risk factor

[0055]

[0056] Beneficial effects:

[0057] The quay crane failure mode risk assessment method based on fuzzy grey correlation in the present invention adopts the idea of ​​grey correlation analysis to rank the risk of quay crane failure modes. Compared with the traditional quay crane failure mode analysis method, it has the following significant advantages:

[0058] 1. The subjective weight and objective weight are aggregated by using the combined weighting method, taking into account the advantages of both subjective weight and objective weight, and the weight of the quay crane risk factor is more reasonable;

[0059] 2. Use fuzzy numbers to represent the evaluation information of failure mode risk factors and integrate the opinions of different experts to reduce the impact of subjective factors on the results;

[0060] 3. The traditional risk decision-making of quay crane failure mode determines the risk priority according to the risk priority RPN, without considering the weight of risk factors. However, through the grey correlation ranking, the weight of risk factors is considered, and the decision result is more reasonable. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 It is a flow chart of the risk assessment method of quay crane failure mode based on fuzzy grey correlation of the present invention. DETAILED DESCRIPTION

[0062] The present invention is further described in detail below with reference to the embodiments.

[0063] Example 1

[0064] The quay crane failure mode risk assessment method based on fuzzy grey correlation includes the following steps:

[0065] Step 1: Establish a quay crane failure mode assessment team to determine the failure mode, as well as the fuzzy comment set and fuzzy weight set of the risk factor occurrence (O), severity (S) and detection (D).

[0066] The failure mode described is an unsafe factor that causes danger to the quay crane;

[0067] Taking the lifting mechanism of a quay crane at a certain port as an example, a risk assessment of its failure mode was conducted. Three members were selected as assessment experts to determine the failure mode of the lifting mechanism of the quay crane, as shown in Table 1.

[0068] Table 1

[0069]

[0070] According to the typical failure modes of lifting mechanism, a fuzzy comment set of risk factors is established, and its meaning is shown in Table 2.

[0071] Table 2

[0072]

[0073] The experts gave a fuzzy weight set of risk factors for the lifting mechanism, and its meaning is shown in Table 3.

[0074] Table 3

[0075] Evaluation language Trapezoidal fuzzy number N (Not important) (0,0,1,2) L (low importance) (1,2,3,4) M(General) (3,4,5,6) H(Important) (5,6,7,8) VH (Very Important) (7,8,9,10)

[0076] Step 2: Aggregate the evaluation information of the risk factors by the assessment team

[0077] In this embodiment, there are 3 (K=3) experts, the number of risk failure modes is 5 (M=5), and the number of risk factors is 3 (N=3).

[0078] The evaluation information of the failure mode of the quay crane hoisting mechanism by three experts (respectively represented by E1, E2, and E3) is shown in Table 4.

[0079] Table 4

[0080]

[0081] The evaluation language given by experts on the subjective weights of risk factors is shown in Table 5.

[0082] Table 5

[0083] Occurrence rate (O) Severity Difficulty of detection (D) Weighted Evaluation Language M H H

[0084] The aggregated risk factor evaluation information is shown in Table 6.

[0085] Table 6

[0086]

[0087] In this embodiment, the trapezoidal fuzzy numbers corresponding to the subjective weights of risk factors given by experts are shown in Table 7.

[0088] Table 7

[0089] Occurrence rate (O) Severity Difficulty of detection (D) Weighted Evaluation Language (3,4,5,6) (5,6,7,8) (5,6,7,8)

[0090] Step 3: Defuzzify the trapezoidal fuzzy numbers of the risk factor evaluation information. The information after evaluation is shown in Table 8.

[0091] Table 8

[0092]

[0093] Step 4: In this embodiment, the smaller the risk factor value is, the better. The clear value of the defuzzified risk factor is normalized to obtain the risk factor matrix R = (r ij ) 5X3 , as shown in Table 9.

[0094] Table 9

[0095] Failure Mode Occurrence rate (O) Severity Difficulty of detection (D) Wire rope diameter becomes thinner C1 0 0.534 0 Wire rope broken strand C2 0.303 0 0.465 Cracks on the reel C3 0.393 0.534 1 Motor insulation reduction C4 1 1 0.767 Motor vibration is too large C5 1 0.534 0.767

[0096] In this embodiment, the smaller the clear value of the risk factor after defuzzification is, the smaller the risk is, and the safer the quay crane hoisting mechanism is (that is, the smaller the value in Table 8, the safer it is).

[0097] Step 5. Similarly, after the subjective weight trapezoidal fuzzy number is defuzzified, the results are shown in Table 10.

[0098] Table 10

[0099] Occurrence rate (O) Severity Difficulty of detection (D) Subjective Weight Deblurring 4.5 6.5 6.5

[0100] In step 6, the explicit values ​​of the subjective weights are normalized and the results are shown in Table 11.

[0101] Table 11

[0102] Occurrence rate (O) Severity Difficulty of detection (D) Subjective weight normalization 0.26 0.37 0.37

[0103] Step 7: Based on the risk factor matrix R and the reference sequence (1,1,1), calculate the grey correlation coefficient matrix ξ=(ξ ij ) 5×3 , as shown in Table 12 below.

[0104] Table 12

[0105] Occurrence rate (O) Severity Difficulty of detection (D) Wire rope diameter becomes thinner C1 0.333 0.518 0.333 Wire rope broken strand C2 0.418 0.333 0.483 Cracks on the reel C3 0.452 0.518 1 Motor insulation reduction C4 1 1 0.682 Motor vibration is too large C5 1 0.518 0.682

[0106] Step 8: Based on the grey correlation coefficient matrix and the entropy weight method, calculate the objective weights of the risk factors as shown in Table 13.

[0107] Table 13

[0108] Occurrence rate (O) Severity Difficulty of detection (D) Objective weight 0.445 0.289 0.265

[0109] Step 9: Based on the improved game theory combined weighting method, the subjective weight and objective weight coefficients are 0.495 and 0.505 respectively. The combined weight vector of the risk factors is shown in Table 14.

[0110] Table 14

[0111] Occurrence rate (O) Severity Difficulty of detection (D) Combination weight 0.36 0.33 0.31

[0112] Step 10, calculate the grey correlation degree of the quay crane failure mode as follows:

[0113] B=w 1×3 ×(ξ 5×3 ) T

[0114] =(0.394, 0.411, 0.646, 0.9, 0.741)

[0115] According to the gray correlation degree, the ranking result of the risk of failure mode of the quay crane lifting mechanism can be known. The smaller the gray correlation degree, the greater the risk. The risk assessment results of the failure mode of the quay crane lifting mechanism are shown in Table 15. Corresponding safety prevention and control measures should be taken for the quay crane lifting mechanism according to the ranking of the risk degree.

[0116] Table 15

[0117] Grey relational degree Risk ranking Wire rope diameter becomes thinner C1 0.394 1 Wire rope broken strand C2 0.411 2 Cracks on the reel C3 0.646 3 Motor insulation reduction C4 0.900 5 Motor vibration is too large C5 0.741 4

[0118] The evaluation method of the present invention and CN110766248A use weighted operators to combine weights and evaluate according to the relative closeness ranking. This patent uses the improved game theory combined weighting method to combine weights and uses gray correlation to perform sorting. Specifically, CN110766248A uses interval intuitive fuzzy numbers, which seem similar in process but different in method. Traditional closeness may cause the problem of reverse order, but the closeness in patent CN110766248A is different from the traditional one, and is not comparable to the present invention in terms of accuracy.

[0119] The above is only a preferred specific implementation manner of the present invention, and the protection scope of the present invention is not limited thereto. Any simple change or equivalent replacement of the technical solution that can be obviously obtained by any technician familiar with the technical field within the technical scope disclosed in the present invention falls within the protection scope of the present invention.

Claims

1. A risk assessment method for quay crane failure mode based on fuzzy grey correlation is characterized by: The steps include: Step 1: Establish a quay crane risk model assessment team to determine the risk model, as well as the fuzzy comment set and fuzzy weight set of risk factors. The elements in the fuzzy comment set are trapezoidal fuzzy numbers, and the elements in the fuzzy weight set are trapezoidal fuzzy numbers. The members of the assessment team are no less than three people; the risk factors are occurrence, severity and detection, and the trapezoidal fuzzy numbers in the fuzzy weight set of risk factors are expressed as In j =(in j(1) ,In j(2) ,In j(3) ,In j(4) ); In the formula, w j Represents the trapezoidal fuzzy weight value of the risk factor, w j(1) is the first number of the weight value of the trapezoidal fuzzy number, w j(2) is the second number that makes up the weight value of the trapezoidal fuzzy number, w j(3) is the third number that makes up the weight value of the trapezoidal fuzzy number, w j(4) is the fourth number that makes up the weight value of the trapezoidal fuzzy number, where the risk factors are occurrence, severity and detection; j represents the serial number of the risk factor, w j When the subscript j is 1, 2, or 3, w1 represents the trapezoidal fuzzy weight value of the occurrence degree, w2 represents the trapezoidal fuzzy weight value of the severity degree, and w3 represents the trapezoidal fuzzy weight value of the detection degree; Step 2: Aggregate the evaluation information of the risk factors by the evaluation team to determine the subjective weights of the risk factors. The calculation method of the subjective weights is as follows: Assume that there are K experts, the number of risk failure modes is M, and the number of risk factors is N. Each expert evaluates all failure modes according to the comment set, and obtains the matrix E (k) for AND (k) =[and (k) ij ] M×N , Where i is the serial number mark of the failure mode, where the value range of i is 1-M, j is the serial number mark of the risk factor, where the value range of j is 1-N, and k is the serial number mark of different experts; the failure modes include thinning of the wire rope diameter, broken wire rope strands, cracks on the drum, reduced insulation of the motor and excessive vibration of the motor; the element e in the matrix (k) ij is the trapezoidal fuzzy number of the risk factor, expressed as: in, Refers to the first to fourth numbers of the trapezoidal fuzzy evaluation value of the jth risk factor of the ith failure mode given by the kth expert; The aggregation function formula for aggregating K expert evaluation information is: Add(e) ij )=Add(e) (1) ij ,And (2) ij ,…,And (k) ij ), Among them, e (1) ij , e (2) ij ,…,e (k) ij is the trapezoidal fuzzy evaluation value of the risk factor of the i-th failure mode j by K experts; Agg(.) is the aggregation function, e ij is the explicit value after defuzzification of the trapezoidal fuzzy number; and Step 3: Defuzzify the trapezoidal fuzzy numbers in the fuzzy comment set of the risk factor. The processing formula is: Among them, e ij(1) , e ij(2) , e ij(3) , e ij(4) are the first to fourth numbers of the trapezoidal fuzzy evaluation values ​​of the risk factor of the i-th failure mode j obtained after aggregating the evaluation information of K experts; e ij is the clear value after defuzzification of the trapezoidal fuzzy number; Step 4: normalize the clear values ​​obtained in step 3 to obtain the matrix R = (r ij ), where the normalized formula for the larger the better risk factor is as follows Among them, mine ij It refers to the minimum value of the clear values ​​after defuzzification of the trapezoidal fuzzy evaluation values ​​of M (i=1, 2, 3, ..., M) failure modes for the jth risk factor; maxe ij It refers to the maximum value among the clear values ​​after defuzzification of the trapezoidal fuzzy evaluation values ​​of M (i=1, 2, 3, ..., M) failure modes for the j-th risk factor; The normalized formula for the smaller the better risk factor is as follows: Step 5, defuzzify the trapezoidal fuzzy number of the subjective weight, and the processing method is the same as step 3; Step 6: normalize the clear value after defuzzification in step 5. The processing formula is: w (1) j is the normalized risk factor weight, which is the subjective weight assigned to the risk factor by experts; Step 7: Based on the risk factor matrix R, the following grey correlation coefficient matrix is ​​calculated as follows: ξ=(ξ ij ) M×N ; The calculation formula of the grey correlation coefficient in the grey correlation coefficient matrix in step 7 is as follows Among them, the gray relational resolution coefficient ζ is taken as 0.5, r oj is the reference value, r ij is the element in the risk factor matrix R; Step 8: Calculate the objective weight of the risk factor based on the grey correlation coefficient matrix. The calculation steps are as follows: Step 8.1, calculate the ratio of the grey correlation coefficient of the i-th risk failure mode under the j-th risk factor: Step 8.2, calculate the entropy of the j-th risk factor Step 8.3, calculate the entropy weight of the j-th risk factor Step 9: Based on the improved game theory combined weighting method, determine the combined weight vector of risk factors: In the formula Among them, w (i) refers to the risk factor weight vector obtained by the ith method, w (i)T w (i) The transpose of (j) refers to the risk factor weight vector obtained by the jth method, w (j)T w (j) The transpose of γ * j is the combination weight coefficient; Step 10: Calculate the grey correlation degree of the failure mode of the quay crane: B=w 1×j ×(ξ ij ) T =(b1,b2,…,b i ,…,b M ), Among them, w 1Xj is a row vector with 1 row and j columns, i.e., the combined weight vector w of risk factors * ; b1, b2, …, b i ,…,b M They refer to the grey relational degree of the first failure mode, the grey relational degree of the second failure mode, the grey relational degree of the ith failure mode, and the grey relational degree of the Mth failure mode respectively; Arrange the elements in vector B in descending order to obtain the risk ranking result of quay crane failure mode. The smaller the grey correlation degree, the greater the risk.

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