Power station boiler main steam pipeline safety assessment method and system

Abstract

The application discloses a power station boiler main steam pipeline safety evaluation method and system, and the method comprises the following steps: obtaining material information of a power station boiler main steam pipeline, wherein the material information comprises crack length and cycle load times of the material; a nonlinear creep damage model for describing material creep is set, and according to the material information, a material creep rate index of the power station boiler main steam pipeline is calculated, and a creep rate threshold is set; when the material creep rate index exceeds the creep rate threshold, an alarm information is sent; or a nonlinear crack growth model for describing material crack growth is set, and according to the material information, a crack growth situation of the material is simulated; when the crack growth exceeds a preset crack growth threshold, an alarm information is sent; or a material failure probability calculation model for describing material failure is set, and according to the material information, a material failure probability is calculated; when the material failure probability exceeds a preset material failure probability threshold, an alarm information is sent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of material safety evaluation of power station boiler main steam pipeline, and more particularly to a power station boiler main steam pipeline safety evaluation method and system. BACKGROUND

[0002] The power station boiler main steam pipeline is one of the most important pressure-bearing components in the boiler system, which is long-term operated in a high-temperature and high-pressure environment, and has a very high safety risk. At present, the domestic DCS system of thermal power generating units mainly focuses on the parameters and operation of the medium in the steam pipeline, and the real-time monitoring of the steam temperature, pressure, flow and the like, which mainly stays at the system level. There is no monitoring and safety evaluation means for the material state of the equipment body, especially the material state of the main steam pipeline in the operation process and the essential safety of the pipeline equipment. It mainly relies on professional personnel and inspection agencies to detect the material state under the condition of stopping the boiler to find out whether there is a problem, which causes the material state feedback to be not timely and not comprehensive. At the same time, with the increase of the service time of the unit, the stress concentration parts such as the weld of the steam pipeline are prone to crack defects under the long-term high-temperature and high-pressure operating environment, the wall thickness of the elbow part is thinned under the high-pressure steam scouring, the whole pipeline will produce creep damage, and the microstructure will cause material degradation with the extension of the operation time.

[0003] Therefore, a technical scheme is needed to evaluate the safety of the material of the power station boiler main steam pipeline, so as to avoid safety risks. SUMMARY

[0004] To solve the above technical problems, the present application provides a power station boiler main steam pipeline safety evaluation method, which comprises:

[0005] Obtaining material information of the power station boiler main steam pipeline, wherein the material information comprises stress, material temperature, microstructure degradation degree, crack length and cycle load number of the power station boiler main steam pipeline;

[0006] Setting a nonlinear creep damage model for describing material creep, and calculating a material creep rate index of the power station boiler main steam pipeline according to the material information, and setting a creep rate threshold, when the material creep rate index exceeds the creep rate threshold, an alarm information is sent out;

[0007] or setting a nonlinear crack growth model for describing material crack growth, and simulating the crack growth of the material according to the material information, when the crack growth exceeds a preset crack growth threshold, an alarm information is sent out;

[0008] or a material failure probability calculation model for describing material failure is set, and a material failure probability is calculated according to the material information, and when the material failure probability exceeds a preset material failure probability threshold, an alarm information is sent out.

[0009] Further, the nonlinear creep damage model comprises:

[0010]

[0011] wherein, is a material creep rate index of the power plant boiler main steam pipeline at time T, A is a material constant of the power plant boiler main steam pipeline creep rate, σ(t) is a stress borne by the power plant boiler main steam pipeline at time t, n is a first adjustment factor of creep, Q c is a creep activation energy, R is a gas constant, T(t) is a material temperature at time t, ξ is a second adjustment factor of creep, φ(t) is a microstructure degradation degree of the material at time t, k is a third adjustment factor of creep, ρ is a fourth adjustment factor of creep, σ(t') is a stress borne by the power plant boiler main steam pipeline at time t', κ(t-t') is a decay rate of material memory effect within time t-t'.

[0012] Further, the nonlinear crack growth model comprises:

[0013]

[0014] wherein, a is a crack length of the material, N is a cyclic load number, C1 is a material constant of crack propagation rate, ΔK(t) is a stress intensity change at the crack tip at time t, ζ is a first adjustment factor of crack growth, T is a temperature of the material, x is a position of the material, m is a second adjustment factor of crack growth, γ is a third adjustment factor of crack growth, η is a fourth adjustment factor of crack growth, and ω is a loading frequency.

[0015] Further, the material failure probability calculation model comprises:

[0016]

[0017] wherein, P fail (t) is a material failure probability at time t, σ(t) is a stress borne by the power plant boiler main steam pipeline at time t, σ avg is an average stress borne by the material, γ is a first adjustment factor of failure probability, T(t) is a temperature of the material at time t, δ is a second adjustment factor of failure probability, is a material temperature gradient at the position x of the material at time t, v is a third adjustment factor of failure probability, h(∈ inhom ) is an influence function of the material heterogeneous strain ∈ inhom .inhom is the heterogeneous strain of the material, which represents the local strain distribution of the material under a complex stress field.

[0018] Furthermore, the material inhomogeneous strain ∈ inhom The influence function h(∈ inhom )include:

[0019]

[0020] Among them, α1 is the first adjustment factor of material heterogeneous strain, β1 is the second adjustment factor of material heterogeneous strain, α2 is the third adjustment factor of material heterogeneous strain, γ′ is the fourth adjustment factor of material heterogeneous strain, α3 is the fifth adjustment factor of material heterogeneous strain, and δ′ is the sixth adjustment factor of material heterogeneous strain.

[0021] The present invention also proposes a power plant boiler main steam pipeline safety assessment system, comprising:

[0022] An information acquisition module is used to acquire material information of a main steam pipe of a power station boiler, wherein the material information includes: stress, material temperature, microstructure degradation degree, crack length of the material, and number of cyclic loads on the main steam pipe of the power station boiler;

[0023] a creep analysis module, configured to set a nonlinear creep damage model for describing material creep, calculate a material creep rate index of a main steam pipe of a power plant boiler based on the material information, and set a creep rate threshold. When the material creep rate index exceeds the creep rate threshold, an alarm is issued;

[0024] Alternatively, a crack growth analysis module is provided for simulating the crack growth of the material according to a nonlinear crack growth model that is set to describe the crack growth of the material and according to the material information, and issuing an alarm message when the crack growth exceeds a preset crack growth threshold;

[0025] Or a material failure analysis module is set up to calculate the material failure probability according to a set material failure probability calculation model describing material failure and the material information, and issue an alarm message when the material failure probability exceeds a preset material failure probability threshold.

[0026] Furthermore, the nonlinear creep damage model includes:

[0027]

[0028] in, is the material creep rate index of the power plant boiler main steam pipe at time t, A is the material constant of the power plant boiler main steam pipe creep rate, σ(t) is the stress received by the power plant boiler main steam pipe at time t, n is the first creep adjustment factor, Q c is the creep activation energy, R is the gas constant, T(t) is the material temperature at time t, ξ is the second creep adjustment factor, φ(t) is the microstructure degradation degree of the material at time t, k is the third creep adjustment factor, ρ is the fourth creep adjustment factor, σ(t') is the stress received by the power plant boiler main steam pipe at time t', κ(t-t') is the decay rate of the material memory effect within time t-t'.

[0029] Further, the nonlinear crack growth model comprises:

[0030]

[0031] wherein a is the crack length of the material, N is the number of cyclic loads, C1 is the material constant of the crack propagation rate, ΔK(t) is the stress intensity change at the crack tip at time t, ζ is the first crack growth adjustment factor, T is the temperature of the material, x is the position of the material, m is the second crack growth adjustment factor, γ is the third crack growth adjustment factor, η is the fourth crack growth adjustment factor, and ω is the loading frequency.

[0032] Further, the material failure probability calculation model comprises:

[0033]

[0034] wherein P fail (t) is the material failure probability at time t, σ(t) is the stress received by the power plant boiler main steam pipe at time t, σ avg is the average stress received by the material, γ is the first failure probability adjustment factor, T(t) is the temperature of the material at time t, δ is the second failure probability adjustment factor, is the material temperature gradient at position x of the material at time t, ν is the third failure probability adjustment factor, h(∈ inhom ) is the influence function of the material heterogeneous strain ∈ inhom , ∈ inhom is the material heterogeneous strain, and represents the local strain distribution of the material under a complex stress field.

[0035] Further, the influence function h(∈ inhom ) of the material heterogeneous strain ∈ inhom comprises:

[0036]

[0037] Wherein, alpha 1 is the first adjustment factor of material inhomogeneous strain, beta 1 is the second adjustment factor of material inhomogeneous strain, alpha 2 is the third adjustment factor of material inhomogeneous strain, gamma' is the fourth adjustment factor of material inhomogeneous strain, alpha 3 is the fifth adjustment factor of material inhomogeneous strain, and delta' is the sixth adjustment factor of material inhomogeneous strain.

[0038] Overall, compared with the prior art, the above technical solutions conceived by the present application have the following beneficial effects:

[0039] The present application can accurately evaluate the safety of the main steam pipeline of the power plant boiler, thereby effectively avoiding the probability of safety accidents and ensuring production safety. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a flow chart of the method of embodiment 1 of the present application;

[0041] Figure 2 is a structural diagram of the system of embodiment 2 of the present application. DETAILED DESCRIPTION

[0042] In order to better understand the above technical solutions, the above technical solutions will be described in detail below in conjunction with the drawings and specific embodiments of the specification.

[0043] The method provided by the present application can be implemented in a terminal environment, which can include one or more of the following components: a processor, a storage medium and a display screen. The storage medium stores at least one instruction, which is loaded and executed by the processor to implement the method described in the following embodiments.

[0044] The processor can include one or more processing cores. The processor connects various parts in the entire terminal through various interfaces and lines, executes the instructions, programs, code sets or instruction sets stored in the storage medium, and calls the data stored in the storage medium to perform various functions and process data of the terminal.

[0045] The storage medium can include random access memory (RAM) and read-only memory (ROM). The storage medium can be used to store instructions, programs, codes, code sets or instructions.

[0046] The display screen is used to display the user interface of each application program.

[0047] In addition, those skilled in the art can understand that the structure of the terminal described above does not constitute a limitation on the terminal, and the terminal can include more or fewer components, or combine certain components, or different component arrangements. For example, the terminal also includes radio frequency circuitry, an input unit, a sensor, audio circuitry, a power supply, and the like, which are not described here.

[0048] Embodiment 1

[0049] As shown in the figure, the embodiment of the application provides a power station boiler main steam pipeline safety assessment method, comprising: Figure 1

[0050] Step 101, obtaining material information of the power station boiler main steam pipeline, wherein the material information includes stress, material temperature, microstructure degradation, crack length and cycle load times of the power station boiler main steam pipeline;

[0051] Step 102, setting a nonlinear creep damage model for describing material creep, and calculating a material creep rate index of the power station boiler main steam pipeline according to the material information, and setting a creep rate threshold, when the material creep rate index exceeds the creep rate threshold, an alarm information is issued;

[0052] Specifically, the nonlinear creep damage model includes:

[0053]

[0054] wherein, is the material creep rate index of the power station boiler main steam pipeline at time t, A is the material constant of the power station boiler main steam pipeline creep rate, σ(t) is the stress of the power station boiler main steam pipeline at time t, n is the first adjustment factor of creep, Q c is the creep activation energy, R is the gas constant, T(t) is the material temperature at time t, ξ is the second adjustment factor of creep, φ(t) is the microstructure degradation of the material at time t, k is the third adjustment factor of creep, ρ is the fourth adjustment factor of creep, σ(t') is the stress of the power station boiler main steam pipeline at time t', κ(t-t') is the decay rate of material memory effect within time t-t'.

[0055] Step 103, or setting a nonlinear crack growth model for describing material crack growth, and simulating the crack growth of the material according to the material information, when the crack growth exceeds a preset crack growth threshold, an alarm information is issued;

[0056] Specifically, the nonlinear crack growth model includes:

[0057] ​

[0058] wherein a is the crack length of the material, N is the number of cyclic loadings, C1 is a material constant of the crack growth rate, ΔK(t) is the stress intensity variation at the crack tip at time t, ζ is a first adjustment factor of the crack growth, T is the temperature of the material, x is the location of the material, m is a second adjustment factor of the crack growth, γ is a third adjustment factor of the crack growth, η is a fourth adjustment factor of the crack growth, and ω is the loading frequency.

[0059] Step 104, or setting a material failure probability calculation model for describing material failure, and calculating the material failure probability according to the material information, and issuing an alarm information when the material failure probability exceeds a preset material failure probability threshold.

[0060] Specifically, the material failure probability calculation model comprises:

[0061]

[0062] wherein P fail (t) is the material failure probability at time t, σ(t) is the stress received by the main steam pipe of the power plant boiler at time t, σ avg is the average stress received by the material, γ is a first adjustment factor of the failure probability, T(t) is the material temperature at time t, δ is a second adjustment factor of the failure probability, is the material temperature gradient at the location x of the material at time t, v is a third adjustment factor of the failure probability, h(∈ inhom ) is the influence function of the material inhomogeneous strain ∈ inhom , and ∈ inhom is the material inhomogeneous strain, indicating the local strain distribution of the material under a complex stress field.

[0063] Specifically, the influence function h(∈ inhom ) of the material inhomogeneous strain ∈ inhom comprises:

[0064]

[0065] wherein α1 is a first adjustment factor of the material inhomogeneous strain, β1 is a second adjustment factor of the material inhomogeneous strain, α2 is a third adjustment factor of the material inhomogeneous strain, γ' is a fourth adjustment factor of the material inhomogeneous strain, α3 is a fifth adjustment factor of the material inhomogeneous strain, and δ' is a sixth adjustment factor of the material inhomogeneous strain.

[0066] Specifically, all the adjustment factors are fitted by a gradient descent method or an ant colony algorithm.

[0067] Embodiment 2

[0068] As Figure 2As shown, the embodiment of the present application also provides a power station boiler main steam pipeline safety assessment system, comprising:

[0069] an information acquisition module configured to acquire material information of the power station boiler main steam pipeline, wherein the material information comprises stress, material temperature, microstructure degradation, crack length and cyclic load number of the power station boiler main steam pipeline;

[0070] a creep analysis module configured to set a nonlinear creep damage model for describing material creep, and calculate a material creep rate index of the power station boiler main steam pipeline according to the material information, and set a creep rate threshold, and when the material creep rate index exceeds the creep rate threshold, an alarm information is sent out;

[0071] Specifically, the nonlinear creep damage model comprises:

[0072]

[0073] wherein, is the material creep rate index of the power station boiler main steam pipeline at time T, A is a material constant of the power station boiler main steam pipeline creep rate, σ(t) is the stress of the power station boiler main steam pipeline at time t, n is a first adjustment factor of creep, Q c is a creep activation energy, R is a gas constant, T(t) is the material temperature at time t, ξ is a second adjustment factor of creep, φ(t) is the microstructure degradation of the material at time t, k is a third adjustment factor of creep, ρ is a fourth adjustment factor of creep, σ(t') is the stress of the power station boiler main steam pipeline at time t', κ(t-t') is the decay rate of material memory effect within time t-t'.

[0074] or a crack growth analysis module is set, configured to simulate crack growth of the material according to a set nonlinear crack growth model for describing material crack growth, and when the crack growth exceeds a preset crack growth threshold, an alarm information is sent out;

[0075] Specifically, the nonlinear crack growth model comprises:

[0076]

[0077] wherein, a is the crack length of the material, N is the cyclic load number, C1 is a material constant of crack propagation rate, ΔK(t) is the stress intensity change at the crack tip at time t, ζ is a first adjustment factor of crack growth, T is the material temperature, x is the position of the material, m is a second adjustment factor of crack growth, γ is a third adjustment factor of crack growth, η is a fourth adjustment factor of crack growth, and ω is the loading frequency.

[0078] or set a material failure analysis module, for calculating the material failure probability according to the set material failure probability calculation model describing the material failure, and calculating the material failure probability according to the material information, and issuing an alarm information when the material failure probability exceeds a preset material failure probability threshold.

[0079] Specifically, the material failure probability calculation model comprises:

[0080]

[0081] Wherein, P fail (t) is the material failure probability at time t, σ(t) is the stress suffered by the main steam pipe of the power plant boiler at time t, σ avg is the average stress suffered by the material, γ is the first adjustment factor of the failure probability, T(t) is the material temperature at time t, δ is the second adjustment factor of the failure probability, is the material temperature gradient at position x of the material at time t, ν is the third adjustment factor of the failure probability, h(∈ inhom ) is the influence function of the material heterogeneous strain ∈ inhom , ∈ inhom is the material heterogeneous strain, and represents the local strain distribution of the material under a complex stress field.

[0082] Specifically, the influence function h(∈ inhom ) of the material heterogeneous strain ∈ inhom comprises:

[0083]

[0084] Wherein, α1 is the first adjustment factor of the material heterogeneous strain, β1 is the second adjustment factor of the material heterogeneous strain, α2 is the third adjustment factor of the material heterogeneous strain, γ' is the fourth adjustment factor of the material heterogeneous strain, α3 is the fifth adjustment factor of the material heterogeneous strain, and δ' is the sixth adjustment factor of the material heterogeneous strain.

[0085] Embodiment 3

[0086] The embodiment of the application further provides a storage medium which stores a plurality of instructions for implementing the power plant boiler main steam pipe safety assessment method.

[0087] Optionally, in the embodiment, the storage medium can be located in any one of computer terminals in a computer terminal group in a computer network, or in any one of mobile terminals in a mobile terminal group.

[0088] Optionally, in the embodiment, the storage medium is configured to store program code for performing the following steps: step 101, obtaining material information of a power plant boiler main steam pipeline, wherein the material information comprises stress borne by the power plant boiler main steam pipeline, material temperature, microstructure degradation degree, crack length of the material, and cycle load number;

[0089] Step 102, setting a nonlinear creep damage model for describing material creep, and calculating a material creep rate index of the power plant boiler main steam pipeline according to the material information, and setting a creep rate threshold, when the material creep rate index exceeds the creep rate threshold, issuing an alarm information;

[0090] Specifically, the nonlinear creep damage model comprises:

[0091]

[0092] wherein, is a material creep rate index of the power plant boiler main steam pipeline at time t, A is a material constant of the power plant boiler main steam pipeline creep rate, σ(t) is stress borne by the power plant boiler main steam pipeline at time t, n is a first adjustment factor of creep, Q c is a creep activation energy, R is a gas constant, T(t) is a material temperature at time t, ξ is a second adjustment factor of creep, φ(t) is a microstructure degradation degree of the material at time t, k is a third adjustment factor of creep, ρ is a fourth adjustment factor of creep, σ(t') is stress borne by the power plant boiler main steam pipeline at time t', κ(t-t') is an attenuation rate of material memory effect within time t-t'.

[0093] Step 103, or setting a nonlinear crack growth model for describing material crack growth, and simulating crack growth of the material according to the material information, when the crack growth exceeds a preset crack growth threshold, issuing an alarm information;

[0094] Specifically, the nonlinear crack growth model comprises:

[0095]

[0096] wherein, a is a crack length of the material, N is a cycle load number, C1 is a material constant of crack propagation rate, ΔK(t) is a stress intensity change at crack tip at time t, ζ is a first adjustment factor of crack growth, T is a material temperature, x is a position of the material, m is a second adjustment factor of crack growth, γ is a third adjustment factor of crack growth, η is a fourth adjustment factor of crack growth, and ω is a loading frequency.

[0097] In step 104, a material failure probability calculation model for describing material failure is set, and a material failure probability is calculated according to the material information; when the material failure probability exceeds a preset material failure probability threshold, an alarm information is sent.

[0098] Specifically, the material failure probability calculation model comprises:

[0099]

[0100] wherein P fail (t) is a material failure probability at time t, σ(t) is a stress received by a main steam pipe of a power station boiler at time t, σ avg is an average stress received by the material, γ is a first adjustment factor of the failure probability, T(t) is a material temperature at time t, δ is a second adjustment factor of the failure probability, is a material temperature gradient at a position x of the material at time t, v is a third adjustment factor of the failure probability, h(∈ inhom ) is an influence function of a material inhomogeneous strain ∈ inhom , and ∈ inhom is the material inhomogeneous strain, representing a local strain distribution of the material under a complex stress field.

[0101] Specifically, the influence function h(∈ inhom ) of the material inhomogeneous strain ∈ inhom comprises:

[0102]

[0103] wherein α1 is a first adjustment factor of the material inhomogeneous strain, β1 is a second adjustment factor of the material inhomogeneous strain, α2 is a third adjustment factor of the material inhomogeneous strain, γ' is a fourth adjustment factor of the material inhomogeneous strain, α3 is a fifth adjustment factor of the material inhomogeneous strain, and δ' is a sixth adjustment factor of the material inhomogeneous strain.

[0104] Embodiment 4

[0105] The embodiment of the present application also provides an electronic device, comprising a processor and a storage medium connected with the processor, wherein the storage medium stores a plurality of instructions, the instructions can be loaded and executed by the processor, so that the processor can execute the power station boiler main steam pipe safety evaluation method.

[0106] Specifically, the electronic device of the embodiment can be a computer terminal, which can comprise one or more processors and a storage medium.

[0107] The storage medium can be used to store software programs and modules, such as the power station boiler main steam pipeline safety evaluation method in the embodiment of the present application, and the corresponding program instructions / modules. The processor executes various functions and data processing by running the software programs and modules stored in the storage medium, that is, the power station boiler main steam pipeline safety evaluation method described above is realized. The storage medium can include a high-speed random storage medium, and can also include a non-volatile storage medium, such as one or more magnetic storage systems, flash memories, or other non-volatile solid-state storage media. In some examples, the storage medium can further include storage media remotely arranged with respect to the processor, and the remote storage media can be connected to the terminal through a network. Examples of the above network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0108] The processor can call the information and application programs stored in the storage medium through the transmission system to execute the following steps: step 101, obtaining material information of the power station boiler main steam pipeline, wherein the material information includes stress, material temperature, microstructure degradation, crack length and cycle load number of the power station boiler main steam pipeline;

[0109] Step 102, setting a nonlinear creep damage model for describing material creep, and calculating a material creep rate index of the power station boiler main steam pipeline according to the material information, and setting a creep rate threshold, and issuing an alarm information when the material creep rate index exceeds the creep rate threshold;

[0110] Specifically, the nonlinear creep damage model includes:

[0111]

[0112] wherein, is the material creep rate index of the power station boiler main steam pipeline at time t, A is the material constant of the creep rate of the power station boiler main steam pipeline, σ(t) is the stress of the power station boiler main steam pipeline at time t, n is the first adjustment factor of creep, Q c is the creep activation energy, R is the gas constant, T(t) is the material temperature at time t, ξ is the second adjustment factor of creep, φ(t) is the microstructure degradation of the material at time t, k is the third adjustment factor of creep, ρ is the fourth adjustment factor of creep, σ(t') is the stress of the power station boiler main steam pipeline at time t', κ(t-t') is the decay rate of the material memory effect within time t-t'.

[0113] Step 103, or setting a nonlinear crack growth model for describing material crack growth, and simulating the crack growth of the material according to the material information, and issuing an alarm information when the crack growth exceeds a preset crack growth threshold.

[0114] Specifically, the nonlinear crack growth model comprises:

[0115]

[0116] wherein a is crack length of the material, N is cycle load number, C1 is material constant of crack propagation rate, ΔK(t) is stress intensity variation at crack tip at time t, ζ is first adjustment factor of crack growth, T is temperature of the material, x is position of the material, m is second adjustment factor of crack growth, γ is third adjustment factor of crack growth, η is fourth adjustment factor of crack growth, and ω is loading frequency.

[0117] Step 104, or setting a material failure probability calculation model for describing material failure, and calculating material failure probability according to the material information, and issuing an alarm information when the material failure probability exceeds a preset material failure probability threshold.

[0118] Specifically, the material failure probability calculation model comprises:

[0119]

[0120] wherein P fail (t) is material failure probability at time t, σ(t) is stress received by the main steam pipe of the power plant boiler at time t, σ avg is average stress received by the material, γ is first adjustment factor of failure probability, T(t) is temperature of the material at time t, δ is second adjustment factor of failure probability, is temperature gradient of the material at position x of the material at time t, v is third adjustment factor of failure probability, h(∈ inhom ) is influence function of material inhomogeneous strain ∈ inhom , and ∈ inhom is material inhomogeneous strain, indicating local strain distribution of the material under complex stress field.

[0121] Specifically, the influence function h(∈ inhom ) of material inhomogeneous strain ∈ inhom comprises:

[0122]

[0123] wherein α1 is first adjustment factor of material inhomogeneous strain, β1 is second adjustment factor of material inhomogeneous strain, α2 is third adjustment factor of material inhomogeneous strain, γ' is fourth adjustment factor of material inhomogeneous strain, α3 is fifth adjustment factor of material inhomogeneous strain, and δ' is sixth adjustment factor of material inhomogeneous strain.

[0124] Embodiment 5

[0125] Embodiment 5 is a supplement to Embodiments 1-4, specifically including: the main steam pipeline safety assessment is evaluated from the aspects of 6 dimensions, 19 indexes, and 5 grades. The 6 dimensions and 19 indexes are as shown in Table 1.

[0126] Table 1: Comprehensive safety assessment table

[0127]

[0128] The influence factors of the 6 dimensions are respectively given different weight factors according to the importance of the influence as shown in Table 2, and the average comprehensive evaluation grade calculation formula 1 is as follows.

[0129] Table 2: Weight factors of influence factors of 6 different dimensions

[0130] Influencing factors Foundation Maintenance Management Operation Monitoring Inspection Weight factor 0.05 0.05 0.1 0.35 0.1 0.35

[0131] Average comprehensive evaluation grade:

[0132] M = ΣL i ×n i (1)

[0133] M—comprehensive safety evaluation grade of main steam pipeline

[0134] L—grade score of influence factor

[0135] n—weight factor

[0136] i-th influence factor

[0137] The influence factors of the 19 indexes are respectively given different weight factors according to the importance of the influence as shown in Table 3, and the average comprehensive evaluation grade calculation formula 1 is as follows.

[0138] Table 3: Weight factors of influence factors of 19 indexes

[0139]

[0140]

[0141] Each of the 19 indexes is given a 5-level score, and then a final comprehensive score is obtained through the weight factor. Finally, the safety state of the pipeline is analyzed through the comprehensive evaluation radar chart.

[0142] The above embodiment numbers of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0143] In the above embodiments of the present application, the description of each embodiment has its own emphasis, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0144] In several embodiments provided by the present application, it should be understood that the disclosed technology can be implemented in other ways. Among them, the above-mentioned system embodiments are only illustrative, for example, the division of the units is only a logical function division, and actual implementation can have another division mode, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units or modules shown or discussed can be indirect coupling or communication connection between the units or modules through some interfaces, and can be electrical or other forms.

[0145] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place or distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0146] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0147] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part of the prior art or the whole or part of the technical solutions can be embodied in the form of a software product, and the computer software product stored in a storage medium includes a plurality of instructions for making a computer device (which can be a personal computer, a server or a network device, etc.) execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes: a U disk, a read-only storage medium (ROM, Read-Only Memory), a random access storage medium (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, and various storage program codes.

[0148] Obviously, the above-mentioned embodiments are only examples for clear illustration, and not limitation of the embodiments. For ordinary skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments need not and cannot be exhausted. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for safety assessment of main steam pipelines of power plant boilers, characterized in that: include: Obtaining material information of a main steam pipe of a power plant boiler, wherein the material information includes: stress, material temperature, microstructure degradation degree, material crack length, and number of cyclic loads on the main steam pipe of the power plant boiler; A nonlinear creep damage model is set for describing material creep, and based on the material information, a material creep rate index of a main steam pipe of a power plant boiler is calculated, and a creep rate threshold is set. When the material creep rate index exceeds the creep rate threshold, an alarm message is issued; The nonlinear creep damage model includes: in, is the material creep rate index of the main steam pipe of the power station boiler at time t, A is the material constant of the creep rate of the main steam pipe of the power station boiler, σ(t) is the stress on the main steam pipe of the power station boiler at time t, n is the first creep adjustment factor, Q c is the creep activation energy, R is the gas constant, T(t) is the material temperature at time t, ξ is the second creep adjustment factor, φ(t) is the microstructural degradation degree of the material at time t, k is the third creep adjustment factor, ρ is the fourth creep adjustment factor, σ(t′) is the stress on the main steam pipe of the power plant boiler at time t′, and κ(tt′) is the decay rate of the material memory effect within time tt′; or setting a nonlinear crack growth model for describing material crack growth, and simulating the crack growth of the material based on the material information, and issuing an alarm message when the crack growth exceeds a preset crack growth threshold; The nonlinear crack growth model includes: Where a is the crack length of the material, N is the number of cyclic loading, C1 is the material constant of the crack growth rate, ΔK(t) is the stress intensity change at the crack tip at time t, ζ is the first adjustment factor for crack growth, T is the temperature of the material, x is the position of the material, m is the second adjustment factor for crack growth, γ is the third adjustment factor for crack growth, η is the fourth adjustment factor for crack growth, and ω is the loading frequency; or setting a material failure probability calculation model for describing material failure, and calculating the material failure probability based on the material information, and issuing an alarm message when the material failure probability exceeds a preset material failure probability threshold; The material failure probability calculation model includes: Among them, P fail (t) is the probability of material failure at time t, σ(t) is the stress on the main steam pipe of the power plant boiler at time t, σ avg is the average stress on the material, γ is the first adjustment factor of the failure probability, T(t) is the material temperature at time t, δ is the second adjustment factor of the failure probability, is the material temperature gradient at the material position x at time t, ν is the third adjustment factor of the failure probability, h(∈ inhom ) is the material inhomogeneous strain ∈ inhom The influence function of inhom is the heterogeneous strain of the material, which represents the local strain distribution of the material under a complex stress field.

2. A method for safety assessment of a main steam pipeline of a power plant boiler according to claim 1, characterized in that: Material inhomogeneous strain ∈ inhom The influence function h(∈ inhom )include: Among them, α1 is the first adjustment factor of material heterogeneous strain, β1 is the second adjustment factor of material heterogeneous strain, α2 is the third adjustment factor of material heterogeneous strain, γ′ is the fourth adjustment factor of material heterogeneous strain, α3 is the fifth adjustment factor of material heterogeneous strain, and δ′ is the sixth adjustment factor of material heterogeneous strain.

3. A power plant boiler main steam pipeline safety assessment system, characterized in that: include: An information acquisition module is used to acquire material information of a main steam pipe of a power station boiler, wherein the material information includes: stress, material temperature, microstructure degradation degree, crack length of the material, and number of cyclic loads on the main steam pipe of the power station boiler; a creep analysis module, configured to set a nonlinear creep damage model for describing material creep, calculate a material creep rate index of a main steam pipe of a power plant boiler based on the material information, and set a creep rate threshold. When the material creep rate index exceeds the creep rate threshold, an alarm is issued; The nonlinear creep damage model includes: in, is the material creep rate index of the main steam pipe of the power station boiler at time t, A is the material constant of the creep rate of the main steam pipe of the power station boiler, σ(t) is the stress on the main steam pipe of the power station boiler at time t, n is the first creep adjustment factor, Q c is the creep activation energy, R is the gas constant, T(t) is the material temperature at time t, ξ is the second creep adjustment factor, φ(t) is the microstructural degradation degree of the material at time t, k is the third creep adjustment factor, ρ is the fourth creep adjustment factor, σ(t′) is the stress on the main steam pipe of the power plant boiler at time t′, and κ(tt′) is the decay rate of the material memory effect within time tt′; Alternatively, a crack growth analysis module is provided for simulating the crack growth of the material according to a nonlinear crack growth model that is set to describe the crack growth of the material and according to the material information, and issuing an alarm message when the crack growth exceeds a preset crack growth threshold; The nonlinear crack growth model includes: Where a is the crack length of the material, N is the number of cyclic loading, C1 is the material constant of the crack growth rate, ΔK(t) is the stress intensity change at the crack tip at time t, ζ is the first adjustment factor for crack growth, T is the temperature of the material, x is the position of the material, m is the second adjustment factor for crack growth, γ is the third adjustment factor for crack growth, η is the fourth adjustment factor for crack growth, and ω is the loading frequency; or setting a material failure analysis module for calculating the material failure probability based on a set material failure probability calculation model describing material failure and the material information, and issuing an alarm message when the material failure probability exceeds a preset material failure probability threshold; The material failure probability calculation model includes: Among them, P fail (t) is the probability of material failure at time t, σ(t) is the stress on the main steam pipe of the power plant boiler at time t, σ avg is the average stress on the material, γ is the first adjustment factor of the failure probability, T(t) is the material temperature at time t, δ is the second adjustment factor of the failure probability, is the material temperature gradient at the material position x at time t, v is the third adjustment factor of the failure probability, h(∈ inhom ) is the material inhomogeneous strain ∈ inhom The influence function of inhom is the heterogeneous strain of the material, which represents the local strain distribution of the material under a complex stress field.

4. A power plant boiler main steam pipeline safety assessment system according to claim 3, characterized in that: Material inhomogeneous strain ∈ inhom The influence function h(∈ inhom )include: Among them, α1 is the first adjustment factor of material heterogeneous strain, β1 is the second adjustment factor of material heterogeneous strain, α2 is the third adjustment factor of material heterogeneous strain, γ′ is the fourth adjustment factor of material heterogeneous strain, α3 is the fifth adjustment factor of material heterogeneous strain, and δ′ is the sixth adjustment factor of material heterogeneous strain.

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