Metal roof performance evaluation method and system based on hierarchical analysis and fuzzy evaluation

Abstract

The present invention discloses a metal roof performance evaluation method and system based on hierarchical analysis and fuzzy evaluation, the method comprising: collecting monitoring index data of the metal roof in different distribution areas of the metal roof, including longitudinal plastic strain value, transverse plastic deformation value, fatigue damage value and historical failure rate; taking the location factor of the distribution area where the metal roof is located as the regional layer index, taking the monitoring index data of the metal roof as the criterion layer factor, and determining the index weight affecting the status evaluation of the metal roof based on the hierarchical analysis method; and determining the metal roof performance evaluation level based on the fuzzy comprehensive evaluation method. The present invention integrates the information of the area where the metal roof is located and the information of the data collected by the monitoring system to realize the comprehensive evaluation of the metal roof in different regions.

Description

Technical Field

[0001] The invention relates to the technical field of metal roof performance evaluation, and more particularly to a metal roof performance evaluation method and system based on hierarchical analysis and fuzzy evaluation. Background Art

[0002] As a new type of building material, metal roofing is widely used in large-span buildings such as stadiums, airports, and industrial plants. The materials used in the metal roof maintenance system are mostly cold-bent thin-walled alloy materials, which integrate various functions such as thermal insulation, sound absorption and sound insulation, waterproof and windproof. At the same time, it has the advantages of light weight, high strength, convenient and flexible construction, etc. It is an emerging building material.

[0003] However, in actual use, metal roofs are more susceptible to various complex weather conditions and pose safety hazards. A comprehensive analysis of the common types of failures currently shows that the main causes of metal roof failures are the following two aspects: The causes of various failures and damage accidents of metal roofs are summarized: On the one hand, there are defects in the specifications and procedures for design, verification and construction of the domestic metal roofing industry, and there is no unified standard to constrain them, resulting in uneven quality of metal roof products. Some metal roof panels are of poor quality and have certain safety hazards. At the same time, there are no standardized construction methods and detection methods in construction, resulting in endless quality accidents of metal roofs. On the other hand, metal roof buildings have been in a complex natural environment for a long time. Natural factors such as wind, rain, and snow have caused long-term corrosion damage and alternating loads, which can easily cause plastic deformation, loose bolts and fatigue effects on metal roofs, which reduces the wind resistance, thermal insulation and waterproofing performance of the metal roof system.

[0004] Therefore, it is of great significance to carry out real-time monitoring of the health status of metal roofs, and it is also crucial to scientifically evaluate the current health status and future remaining life of metal roofs based on monitoring data. Summary of the invention

[0005] In view of this, the present invention provides a metal roof performance evaluation method and system based on hierarchical analysis and fuzzy evaluation, which integrates the information of the area where the metal roof is located and the information of data collected by the monitoring system to conduct a comprehensive evaluation of the metal roof in different regions.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] The metal roof performance evaluation method based on hierarchical analysis and fuzzy evaluation includes:

[0008] The monitoring index data of the metal roof are collected in different distribution areas of the metal roof, including longitudinal plastic strain value, transverse plastic deformation value, fatigue damage value and historical failure rate;

[0009] The location factor of the distribution area of ​​metal roofs is used as the regional layer index, and the monitoring index data of metal roofs is used as the criterion layer factor. The weight of the index affecting the status assessment of metal roofs is determined based on the hierarchical analysis method.

[0010] The performance evaluation grade of metal roof is determined by fuzzy comprehensive evaluation method based on index weights.

[0011] Preferably, the different distribution areas of the metal roof include a general area, a building edge area and a windward area, wherein the general area is the center of the roof and is less affected by weather factors, while the building edge area and the windward area are increasingly affected by weather factors.

[0012] Preferably, the specific steps of collecting the longitudinal plastic strain value are:

[0013] The strain data of the metal roof is collected by n strain gauge sensors arranged in the same distribution area. The data is weighted and summed according to the pasting position of the metal roof strain gauge as the longitudinal plastic strain value of the area. The calculation formula is:

[0014] Y=a1Y1+a2Y2+…+a n Y n

[0015] Where, Y1, Y2, ....., Y n is the strain data time series collected by n strain gauge sensors, a1, a2, ..., a n are the weights of n regions, and the sum of the total weights is 1.

[0016] Preferably, the specific steps of collecting the transverse plastic deformation value are:

[0017] The displacement data of the metal roof is collected by n displacement sensors arranged in the same distribution area. The data is weighted and summed according to the pasting position of the metal roof strain gauge as the lateral plastic strain value of the area. The calculation formula is:

[0018] Z=b1Z1+b2Z2+…+b n Z n

[0019] Where Z1, Z2, ....., Z n is the strain data time series collected by n displacement sensors, b1, b2, ..., b n are the weights of n regions, and the sum of the total weights is 1.

[0020] Preferably, the fatigue damage value calculation formula is:

[0021]

[0022] In the formula, k represents the number of cycles of cyclic loads on the metal roof, H D Indicates the cumulative effect of each cyclic stress on the performance of the metal roof, β i is the weight of the damage amount corresponding to the i-th deformation. The larger the stress amplitude, the larger the corresponding weight. i The magnitude is σ i The corresponding material fatigue life under the continuous action of symmetrical cyclic stress, that is, the number of stress cycles at which damage occurs, σ u Set according to engineering experience.

[0023] Preferably, the historical failure rate calculation formula is:

[0024]

[0025] In the formula, T represents the time period, F i Indicates the number of fault warnings that occurred.

[0026] Preferably, the location factor of the distribution area where the metal roof is located is used as the regional layer indicator, and the monitoring index data of the metal roof is used as the criterion layer factor. The weight of the indicator affecting the status assessment of the metal roof is determined based on the hierarchical analysis method, which specifically includes:

[0027] 1) Establish a hierarchical analysis model: take the location factors of the distribution area of ​​the metal roof as the regional layer indicators, including the general area, the outer edge area of ​​the building and the windward area, take the monitoring index data of the metal roof as the criterion layer factors, including the longitudinal plastic strain value, the transverse plastic deformation value, the fatigue damage value and the historical failure rate, and take the comprehensive performance evaluation results of the metal roof as the target layer;

[0028] 2) Establish factor set and judgment set:

[0029] Calculate the factor set based on the number of monitoring indicators in the distribution area;

[0030] The comprehensive performance evaluation results of metal roofs were divided into five levels as the evaluation set;

[0031] 3) Determine the indicator weights: Establish a comparison matrix based on the monitoring indicator data of the metal roof corresponding to each distribution area, and determine the weights of the longitudinal plastic strain value, transverse plastic deformation value, fatigue damage value and historical failure rate.

[0032] Preferably, determining the metal roof performance evaluation grade based on the fuzzy comprehensive evaluation method specifically includes:

[0033] Determine the specific levels of longitudinal plastic strain value, transverse plastic deformation value, fatigue damage value and historical failure rate of different distribution areas of metal roofs, define scores for each level, and establish a membership matrix;

[0034] The metal roof performance evaluation grade is determined by multiplying the membership matrix and the index weight.

[0035] The metal roof performance evaluation system based on hierarchical analysis and fuzzy evaluation includes: data acquisition module, data processing module and performance evaluation module;

[0036] The data acquisition module is used to collect monitoring data of the metal roof in different distribution areas of the metal roof, including longitudinal plastic strain value, transverse plastic deformation value, fatigue damage value and historical failure rate;

[0037] The data processing module is used to take the location factor of the distribution area where the metal roof is located as the regional layer index, take the monitoring data of the metal roof as the criterion layer factor, and determine the index weight affecting the status assessment of the metal roof based on the hierarchical analysis method;

[0038] The performance evaluation module determines the metal roof performance evaluation grade based on the fuzzy comprehensive evaluation method.

[0039] Through the above technical solutions, it can be known that compared with the prior art, the present invention discloses a metal roof performance evaluation method and system based on hierarchical analysis and fuzzy evaluation. The hierarchical analysis method is combined with the fuzzy comprehensive evaluation method to combine the location factor of the metal roof area with the monitoring quantity collected by the metal roof monitoring system, and the heterogeneity and distribution characteristics of the sensor are fully considered. In the process of utilizing heterogeneous information, the longitudinal strain information, lateral displacement information, fault alarm number and fatigue cumulative damage of the metal roof collected by the heterogeneous sensor are used as the main factors for evaluating the degradation process of the metal roof, and the performance of the metal roof is comprehensively evaluated. In terms of the health assessment of the metal roof system, the hierarchical analysis method can better utilize multiple indicators, including all sensor information in the entire monitoring system, to evaluate the health status of the metal roof system. At the same time, the method integrates fuzzy evaluation, which can solve the problem that some factors cannot be quantified in the actual use process, and is convenient for converting qualitative problems in the metal roof system into quantitative problems for analysis, making the evaluation results clearer and more convenient for us to intuitively obtain the real-time performance status of the current metal roof system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0041] Figure 1The accompanying drawing is a schematic flow chart of a metal roof performance evaluation method based on hierarchical analysis and fuzzy evaluation provided by the present invention.

[0042] Figure 2 The accompanying drawing is a schematic diagram of the hierarchical analysis model provided by the present invention. DETAILED DESCRIPTION

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The embodiment of the present invention discloses a metal roof performance evaluation method based on hierarchical analysis and fuzzy evaluation, such as Figure 1 As shown, including:

[0045] Step 1: Determine the evaluation index of the metal roof, and then collect the monitoring data of the metal roof in different distribution areas of the metal roof.

[0046] In the process of building the metal roof online monitoring system, strain gauges and displacement sensors are installed in different areas of the metal roof to measure the strain and displacement information of different parts of the metal roof enclosure system to reflect the performance indicators of different areas of the metal roof and establish the fatigue performance indicators of the metal roof. While considering the performance indicators, the distribution area of ​​the metal roof is also one of the factors to be considered. The distribution area of ​​the metal roof can be divided into three parts: the ordinary area, the outer edge area of ​​the building and the windward area. The ordinary area is the center of the roof and is less affected by weather factors. The outer edge area of ​​the building and the windward area are affected by weather factors in turn. When dividing the degradation level of the metal roof, the monitoring data and location factors of the metal roof should be fully considered. The metal roof rating is determined by two indicators. When the metal roof rating is low, the areas where the metal roof performance is severely degraded can be repaired and replaced in a targeted manner.

[0047] According to the distribution of monitoring systems in actual use, the following metal roof evaluation indicators are generally defined in combination with the data that can be collected:

[0048] (1) Longitudinal plastic strain of metal roof

[0049] Strain gauges are arranged on the surface of the metal roof to measure the longitudinal strain of the metal roof panel. The strain of the metal roof in a static state is the plastic strain of the metal roof. The plastic strain reflects the plastic deformation of the metal roof. Under normal circumstances, since the metal roof is a linear elastic material, the metal roof can return to its original state after external loads such as wind loads, that is, there is no plastic strain. When the metal roof is under long-term alternating load conditions, the metal roof will undergo plastic deformation and cannot return to its initial state, resulting in a decrease in the metal roof's ability to resist external loads. Therefore, the plastic strain residual of the strain gauge is selected as one of the criteria for measuring the degradation performance of the metal roof.

[0050] The plastic strain of the metal roof is calculated by collecting data from strain gauges. The evaluation of the metal roof is carried out in different areas. n strain gauges are arranged in the same area to collect the strain of the metal roof. During the collection process, the data is weighted and summed according to the location of the metal roof strain gauges as the longitudinal plastic strain value of the area. The data measured on the windward side and the outer edge of the building have a higher weight because the load on this area is larger. At the same time, it should be ensured that data from sunny weather is selected for evaluation during the data collection process to prevent large-scale data fluctuations caused by weather conditions. For the strain data time series Y1, Y2,....., Y collected by multiple sensors in general, n , then the calculation formula for the comprehensive longitudinal plastic strain value of this area is as follows:

[0051]

[0052] a1,a2,......,a n are the weights of n areas. The weights are divided according to the different collection areas. Key monitoring areas can adjust higher weights. The sum of the total weights is 1.

[0053] The present invention calculates the difference between the time series obtained at the end of the evaluation period and the beginning of the evaluation period to obtain the difference time series of the plastic deformation of the metal roof within the evaluation period, and evaluates the plastic strain of the metal roof by calculating the average value of the difference time series as the plastic strain value.

[0054] According to some studies, metal roofs can be considered to have failed when their strain value exceeds 0.05. Therefore, the longitudinal plastic strain state of metal roofs can be divided into level 1: 0-0.01, level 2: 0.01-0.02, level 3: 0.02-0.03, level 4: 0.03-0.04, and level 5: above 0.04 based on the calculated longitudinal plastic strain value data. It is generally believed that the higher the level, the higher the degree of degradation of the metal roof. The plastic deformation of metal roofs above level 5 will seriously reduce the wind resistance and other performance of the metal roof, and it is necessary to consider repair and replacement.

[0055] (2) Transverse plastic deformation of metal roof

[0056] In the metal roof online monitoring system, the transverse plastic deformation of the metal roof is also an important indicator for metal roof online monitoring. At the same time, as the metal roof is used for a longer time, the transverse plastic deformation of the metal roof can also be used as an important reference indicator for evaluating the metal roof performance degradation model, which has an important impact on the performance degradation of the metal roof. Similar to the longitudinal plastic strain, excessive transverse plastic deformation will also affect the metal roof's ability to resist external loads. According to current research, the generally allowed plastic deformation in engineering is 10% of the material's service length, so 10% of the length of the metal roof panel is selected as the failure threshold.

[0057] When analyzing the plastic deformation of the metal roof, the weighted average value of the displacement sensor data collected in the evaluation area is also selected as the evaluation data. The calculation formula is:

[0058] Z=b1Z1+b2Z2+…+b n Z n

[0059] Where Z1, Z2, ....., Z n is the strain data time series collected by n displacement sensors, b1, b2, ..., b n is the weight of n areas, the total weight sum is 1, and Z is the weight of the strain data collected by the displacement sensor.

[0060] The present invention calculates the average value of the time series difference of the transverse plastic displacement of the metal roof at the end and the beginning of the evaluation period, and performs a graded evaluation on the transverse plastic displacement of the metal roof. The specific grading situation can be analyzed according to the failure ratio in combination with the actual plate length.

[0061] (3) Fatigue damage

[0062] In the process of selecting fatigue damage index, the fatigue damage accumulation value H can be used. D As the evaluation standard, according to the linear damage accumulation criterion, the following formula is used for calculation:

[0063]

[0064] Where k represents the number of cycles of cyclic loads on the metal roof, H D It indicates the cumulative effect of each cyclic stress on the performance of the metal roof. i is the weight of the damage amount corresponding to the i-th deformation. The larger the stress amplitude, the larger the corresponding weight. N i The magnitude is σ iThe fatigue life of the material under the continuous action of symmetrical cyclic stress, that is, the number of stress cycles at which damage occurs. u According to engineering experience, it is usually set to 200kPa. The fatigue damage of metal roofs can be classified into level 1: 0-0.2, level 2: 0.2-0.4, level 3: 0.4-0.6, level 4: 0.6-0.8, and level 5: 0.8-1.

[0065] (4) Historical failure rate

[0066] Usually, the faults encountered during the metal roof monitoring process are recorded to facilitate the subsequent tracing of the fault type and fault occurrence time. Therefore, the failure rate of the monitored area can be selected as one of the indicators for evaluating the health status of the metal roof.

[0067] The historical failure rate is defined as H p , the definition is:

[0068]

[0069] The historical failure rate indicates the number of failure warnings F that occurred within a time period T. i , and according to F i The size of H is used to classify the historical failure rate of metal roofs. p <1 / month is level 1, when 1 / month <H p <1 / week is level 2, when 1 / week <H p <1 / month is level 3, when 1 / day <H p <1 / is level 4, when H p >1 / hour is level 5.

[0070] Step 2: Determine indicator weights based on analytic hierarchy process

[0071] (1) Establishing a hierarchical analysis model

[0072] The purpose of using the analytic hierarchy process to evaluate the performance of metal roofs is to give the weights of each indicator that affects the metal roof under the premise of artificially determining the importance of each indicator, so as to comprehensively consider the various factors that affect the performance of the metal roof and conduct a comprehensive evaluation of the status of the metal roof. In the process of hierarchical analysis, it is necessary to divide the various indicators that affect the performance evaluation results of the metal roof into the target layer, the regional layer, and the criterion layer. The location factor of the area where the metal roof is located is used as the regional layer indicator, which includes the ordinary area D1, the outer edge area of ​​the building D2, and the windward area D3. The evaluation indicators based on monitoring data are used as criterion layer factors, including the plastic strain y of the metal roof. z , transverse plastic deformation y h , fatigue damage D And the fault alarm rate H p .

[0073] (2) Establish factor set and judgment set

[0074] Factor set: determined according to the number of indicators in the region. The present invention is divided into three regions, each with four indicators, for a total of 12 indicators.

[0075] Evaluation set: The comprehensive performance evaluation results of metal roofs are divided into five levels. As the level increases, the performance gradually decreases, so Level I has the best performance and Level V is the lowest.

[0076] (3) Determine indicator weights

[0077] The use of the analytic hierarchy process can quantitatively calculate the influence of each factor on the evaluation result under the condition of adding human factors, and give the influence weight of each factor on the evaluation result, so as to make decisions on complex problems that are difficult to solve with quantitative methods. When evaluating the performance indicators of the metal roof, the present invention needs to comprehensively consider the location of the metal roof and the various monitoring indicators of the metal roof.

[0078] In order to determine the indicator weights, we first need to construct a comparison matrix and define the matrix scale, where scale 1 represents that the two factors are equally important, scale 3 represents that the two factors are slightly more important than the latter, scale 5 represents that the two factors are significantly more important than the latter, scale 7 represents that the two factors are strongly more important than the latter, scale 9 represents that the two factors are extremely important than the latter, and 2, 4, 6, and 8 represent the importance levels between the above judgments. There are four corresponding monitoring indicators for each area, and there are three roof distribution areas. Their importance scales are shown in Tables 1 and 2 respectively:

[0079] Table 1 Importance scale of layer evaluation indicators

[0080]

[0081] Table 2 Roof location importance scale

[0082]

[0083] According to the above table, we can get the comparison matrix A, and according to the properties of the matrix, we can get AW = λ max W,λ max Represents the maximum eigenvalue, and then determines the weight of each indicator. The total weight of each factor can be obtained by multiplying the weights of the two levels, that is, the importance scale matrix of the target layer to the regional layer is obtained. and the importance scale matrix of the regional layer to the criterion layer After that, the weight index of the target layer for the criterion layer can be obtained by calculating the product of the two-layer weight index; the weight vector W can be normalized to obtain the weights of each index that ultimately affects the performance evaluation of the metal roof.

[0084] Combining the above table with the eigenvalue calculation method of the matrix, we can obtain the weight index of the impact of different fault forms in different areas of the metal roof on the status assessment of the metal roof. This index is a quantitative description of the influencing factors.

[0085] Step 3: Determine the evaluation level using fuzzy comprehensive evaluation method

[0086] In order to combine the evaluation results of multiple evaluation indicators to obtain the final evaluation result, the fuzzy comprehensive evaluation method is used to make a final evaluation of the status of the metal roof. Each monitoring indicator of the metal roof has been divided into five levels. In order to facilitate the fuzzy evaluation of the metal roof, the five levels are respectively corresponding to 0.1-0.9 points, and the final rating of the metal roof is determined by the score. Level 1 is defined as 0.9 points, level 2 is defined as 0.7 points, level 3 is defined as 0.5 points, level 4 is defined as 0.3 points, and level 5 is defined as 0.1 points.

[0087] According to the indicators, the membership function is established:

[0088]

[0089] Where n is an evaluation factor. In the present invention, it includes a common area, a building outer edge area and a windward area. Each area has 4 evaluation indicators, so n=12, and m is the number of evaluation levels.

[0090] The comprehensive evaluation grade B of the metal roof is obtained by multiplying the weight factor W and the membership matrix, B=WR, and the grade with the highest proportion in grade B is the final evaluation result of the metal roof.

[0091] The final evaluation grade of the metal roof is obtained through calculation and comprehensive comparison.

[0092] In an embodiment, a performance evaluation system corresponding to the above-mentioned metal roofing performance evaluation method based on hierarchical analysis and fuzzy evaluation is disclosed, including: a data acquisition module, a data processing module and a performance evaluation module;

[0093] The data acquisition module is used to collect monitoring data of the metal roof in different distribution areas of the metal roof, including longitudinal plastic strain value, transverse plastic deformation value, fatigue damage value and historical failure rate;

[0094] The data processing module is used to take the location factor of the distribution area where the metal roof is located as the regional layer index, take the monitoring data of the metal roof as the criterion layer factor, and determine the index weight affecting the status assessment of the metal roof based on the hierarchical analysis method;

[0095] The performance evaluation module determines the metal roof performance evaluation grade based on the fuzzy comprehensive evaluation method.

[0096] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0097] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A metal roof performance evaluation method based on hierarchical analysis and fuzzy evaluation, characterized in that: include: The monitoring index data of the metal roof are collected in different distribution areas of the metal roof, including longitudinal plastic strain value, transverse plastic deformation value, fatigue damage value and historical failure rate; The location factor of the distribution area of ​​metal roofs is used as the regional layer index, and the monitoring index data of metal roofs is used as the criterion layer factor. The weight of the index affecting the status assessment of metal roofs is determined based on the hierarchical analysis method. The metal roof performance evaluation grade is determined by fuzzy comprehensive evaluation method based on index weights; The specific steps for collecting longitudinal plastic strain values ​​are as follows: The strain data of the metal roof is collected by n strain gauge sensors arranged in the same distribution area. The data is weighted and summed according to the pasting position of the metal roof strain gauge as the longitudinal plastic strain value of the area. The calculation formula is: In the formula, is the strain data time series collected by n strain gauge sensors, is the weight of n regions, and the sum of the total weights is 1; The specific steps for collecting transverse plastic deformation values ​​are as follows: The displacement data of the metal roof is collected by n displacement sensors arranged in the same distribution area. The data is weighted and summed according to the pasting position of the metal roof strain gauge as the lateral plastic strain value of the area. The calculation formula is: In the formula, is the strain data time series collected by n displacement sensors, is the weight of n regions, and the total weight sum is 1; the location factor of the distribution area where the metal roof is located is used as the regional layer indicator, and the monitoring index data of the metal roof is used as the criterion layer factor. The weight of the indicator affecting the status assessment of the metal roof is determined based on the hierarchical analysis method, which specifically includes: 1) Establish a hierarchical analysis model: take the location factors of the distribution area of ​​the metal roof as the regional layer indicators, including the general area, the outer edge area of ​​the building and the windward area; take the monitoring index data of the metal roof as the criterion layer factors, including the longitudinal plastic strain value, the transverse plastic deformation value, the fatigue damage value and the historical failure rate; take the comprehensive performance evaluation results of the metal roof as the target layer; 2) Establish factor set and judgment set: Calculate the factor set based on the number of monitoring indicators in the distribution area; The comprehensive performance evaluation results of metal roofs were divided into five levels as the evaluation set; 3) Determine the indicator weights: Establish a comparison matrix based on the monitoring indicator data of the metal roof corresponding to each distribution area, and determine the weights of the longitudinal plastic strain value, transverse plastic deformation value, fatigue damage value and historical failure rate.

2. The metal roof performance evaluation method based on hierarchical analysis and fuzzy evaluation according to claim 1 is characterized in that: The different distribution areas of metal roofs include ordinary areas, building edge areas and windward areas. The ordinary area is the center of the roof and is less affected by weather factors. The building edge areas and windward areas are affected by weather factors more and more.

3. The metal roof performance evaluation method based on hierarchical analysis and fuzzy evaluation according to claim 1 is characterized in that: The fatigue damage value calculation formula is: In the formula, k represents the number of cycles of cyclic loads on the metal roof, H D It indicates the cumulative effect of each cyclic stress on the performance of the metal roof. is the weight of the damage amount corresponding to the i-th deformation. The larger the stress amplitude, the larger the corresponding weight. is the cyclic stress amplitude, Set according to engineering experience.

4. The metal roof performance evaluation method based on hierarchical analysis and fuzzy evaluation according to claim 1 is characterized in that: The historical failure rate is calculated as follows: In the formula, T represents the time period, F i Indicates the number of fault warnings that occurred.

5. The metal roof performance evaluation method based on hierarchical analysis and fuzzy evaluation according to claim 1 is characterized in that: The performance evaluation level of metal roofing determined based on the fuzzy comprehensive evaluation method includes: Determine the specific levels of longitudinal plastic strain value, transverse plastic deformation value, fatigue damage value and historical failure rate of different distribution areas of metal roofs, define scores for each level, and establish a membership matrix; The metal roof performance evaluation grade is determined by multiplying the membership matrix and the index weight.

6. A metal roof performance evaluation system based on hierarchical analysis and fuzzy evaluation, the system being used to implement any of the methods described in claims 1-5, characterized in that: include: Data acquisition module, data processing module and performance evaluation module; The data acquisition module is used to collect monitoring data of the metal roof in different distribution areas of the metal roof, including longitudinal plastic strain value, transverse plastic deformation value, fatigue damage value and historical failure rate; The data processing module is used to take the location factor of the distribution area where the metal roof is located as the regional layer index, take the monitoring data of the metal roof as the criterion layer factor, and determine the index weight affecting the status assessment of the metal roof based on the hierarchical analysis method; The performance evaluation module determines the metal roof performance evaluation grade based on the fuzzy comprehensive evaluation method.

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