A method, device, medium and equipment for assessing the remaining life of a jacket platform

Abstract

The present invention discloses a method, device, medium and equipment for assessing the remaining life of a jacket platform, and relates to the technical field of marine platform structural safety assessment. The method comprises: establishing a multi-fidelity digital model of the jacket platform structure; identifying the marine environmental load of the overall finite element model; correcting the boundary conditions of the overall finite element model based on measured acceleration data to obtain an overall corrected model; correcting the local finite element correction model in the overall corrected model based on measured local strain response data to obtain a local corrected model; correcting the load parameters in the marine environmental load calculation formula to obtain a corrected multi-fidelity digital model; establishing a load prediction model; using the output of the load prediction model as a force boundary input, performing fatigue analysis on the overall digital model in the corrected multi-fidelity digital model to obtain accumulated damage, and calculating the remaining fatigue life. The present invention can improve the accuracy of jacket platform life prediction.

Description

Technical Field

[0001] The present application relates to the technical field of offshore platform structure safety assessment, and in particular to a method, device, medium and equipment for assessing the remaining life of a jacket platform. Background Art

[0002] Research on condition assessment and remaining life prediction for aging, in-service offshore platform structures has become a hot topic within the industry. Accurately assessing the current condition of a platform structure is fundamental to subsequent remaining life prediction. Currently, remaining life prediction for aging jacket platform structures is mostly based on calculations performed during the design phase, lacking an accurate description of the platform's current state, resulting in insufficient remaining life prediction accuracy. For example, patent publication number CN118395808 A discloses a "jacket platform digital twin method and apparatus." The inventors of this disclosure discovered that this method and apparatus primarily reflects the actual conditions of the platform structure through load inversion. Patent publication number CN116108726 A discloses a "fixed-offshore platform inspection method, apparatus, and device." This method assesses the structural condition of the digital twin model using the fixed platform's real-time marine environment, but fails to consider the impact of structural parameter changes on the platform's structure, which in turn affects the remaining life. Furthermore, domestic and international patents for assessing aging jacket platform structures still rely on monitoring systems or detection methods, with limited research on remaining life prediction.

[0003] In summary, the accuracy of the remaining life prediction of an aging jacket platform structure in the prior art is relatively low. Summary of the Invention

[0004] Based on this, it is necessary to provide a method, device, medium and equipment for assessing the remaining life of a jacket platform in response to the above technical problems.

[0005] This manual adopts the following technical solutions:

[0006] A method for assessing the remaining life of a jacket platform, comprising:

[0007] Establish a multi-fidelity digital model of the jacket platform structure; the multi-fidelity digital model includes an overall finite element model and an overall digital model;

[0008] Determine the local finite element model of the jacket platform from the overall finite element model, and identify the marine environmental loads of the overall finite element model based on the measured local strain response data of the local finite element model;

[0009] Based on the measured acceleration data of the overall finite element model, the boundary conditions of the overall finite element model are corrected to obtain the overall corrected model;

[0010] The local finite element correction model in the overall correction model is corrected based on the measured local strain response data to obtain a local correction model; wherein the local finite element correction model is obtained by correcting the boundary conditions of the local finite element model;

[0011] Based on the local correction model and the time-varying curve of the ocean environmental load, combined with the measured local strain response data and wave meter test data, the load parameters in the ocean environmental load calculation formula are corrected to obtain a corrected multi-fidelity digital model; among which the wave meter test data is data obtained using a wave meter;

[0012] Based on historical load identification data, a load prediction model considering the impact of uncertainty is established;

[0013] The output of the load prediction model is used as the force boundary input to perform fatigue analysis on the overall digital model in the modified multi-fidelity digital model to obtain the accumulated damage and calculate the remaining fatigue life.

[0014] Acquire measured acceleration data and perform preprocessing to obtain preprocessed measured acceleration data;

[0015] The random subspace method is used to calculate the modal parameters of the jacket platform structure and obtain the test mode;

[0016] Use ANSYS solver to solve the modes of the overall finite element model and obtain the calculated modes;

[0017] Based on the test mode, the parameters to be corrected are selected through sensitivity analysis, and the overall finite element model is corrected to obtain the overall corrected model; wherein, the convergence judgment condition of the correction is that the relative error between the test mode and the calculated mode is less than a first preset error threshold.

[0018] Optionally, an overall finite element model of the jacket platform structure is established, specifically including:

[0019] The beam188 element was used to establish the finite element model of the pile legs, struts, chords, cross braces, and diagonal braces. The shell181 element was used to establish the finite element model of the main deck, production deck, bottom deck, and spider deck. The combine39 nonlinear spring element was used at the bottom of the pile legs to simulate the nonlinear boundary of the pile foundation inserted into the seabed. This resulted in a finite element model of the bottom of the pile legs and the overall finite element model.

[0020] Determine the local finite element model of the jacket platform from the overall finite element model, including:

[0021] The long-term distribution of fatigue stress range is simulated by two-parameter Weibull distribution, and the allowable stress range method is used to perform simplified fatigue analysis on the overall finite element model to determine the local finite element model.

[0022] Optionally, based on the measured local strain response data of the local finite element model, identifying the marine environmental load of the overall finite element model specifically includes:

[0023] Perform stress analysis on the local finite element model to determine the load form of the local finite element model and decompose the load on the local finite element model in the nodal coordinate system;

[0024] Analyze the local finite element model under the action of the decomposed load alone to obtain the strain mode of the local finite element model under each load;

[0025] The strain sensor layout positions of the local finite element model are determined by combining the D optimization algorithm with the greedy algorithm, and sensors are installed at the strain sensor layout positions to obtain the measured local strain response data of the local finite element model;

[0026] According to the strain mode and measured local strain response data, the load coefficient matrix is ​​obtained by numerical method.

[0027] The external load matrix of the local finite element model is obtained by solving the load coefficient matrix;

[0028] Based on the external load matrix, the marine environmental load is derived.

[0029] Optionally, the local finite element correction model in the overall correction model is corrected based on the measured local strain response data to obtain the local correction model, specifically including:

[0030] Acquiring strain sensor test data and performing preprocessing to obtain preprocessed strain sensor test data;

[0031] The local finite element modified model was calculated using the ANSYS solver to obtain the time-varying strain curve of the local finite element modified model under the action of marine environmental loads.

[0032] Based on the time-varying strain curve, the physical parameters to be corrected of the local finite element correction model are determined through sensitivity analysis and correction is performed to obtain the local correction model; wherein, the convergence judgment condition of the correction is that the relative error between the strain test value and the finite element calculation value is less than a second preset error threshold.

[0033] Optionally, based on the local correction model and the time-varying curve of the ocean environmental load, combined with the measured local strain response data and wave meter test data, the load parameters in the ocean environmental load calculation formula are corrected, specifically including:

[0034] Acquire and process wave meter test data to obtain the equivalent wave height time-varying curve;

[0035] Based on the measured local strain response data and the time-varying curve of equivalent wave height, the load parameters in the marine environmental load are corrected.

[0036] Optionally, a load prediction model that takes uncertainty into account is established based on historical load identification data, specifically including:

[0037] A Gaussian regression model is established based on historical load identification data and embedded into the Morrison equation to obtain the load prediction model.

[0038] This specification provides a device for assessing the remaining life of a jacket platform, including:

[0039] The model building module is specifically used to establish a multi-fidelity digital model of the jacket platform structure; the multi-fidelity digital model includes an overall finite element model and an overall digital model; a local finite element model of the jacket platform of particular interest is determined from the overall finite element model; and the marine environmental loads of the overall finite element model are identified based on the measured local strain response data of the local finite element model;

[0040] The model correction module is specifically used to correct the boundary conditions of the overall finite element model based on the measured acceleration data of the overall finite element model to obtain the overall corrected model; correct the local finite element correction model in the overall corrected model based on the measured local strain response data to obtain the local corrected model; wherein the local finite element correction model is obtained by correcting the boundary conditions of the local finite element model; based on the local corrected model and the time-varying curve of the marine environmental load, combined with the measured local strain response data and the wave meter test data, the load parameters in the marine environmental load calculation formula are corrected to obtain a corrected multi-fidelity digital model; wherein the wave meter test data is data obtained using a wave meter;

[0041] The life prediction module is specifically used to establish a load prediction model that takes into account the influence of uncertainty based on historical load identification data; the output results of the load prediction model are used as force boundary input to perform fatigue analysis on the overall digital model in the revised multi-fidelity digital model to obtain the cumulative damage and calculate the remaining fatigue life.

[0042] This specification provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the aforementioned method for assessing the remaining life of a jacket platform is implemented.

[0043] At least one of the above technical solutions adopted in this specification can achieve the following beneficial effects:

[0044] In the remaining life assessment method of the jacket platform provided in this specification, a multi-fidelity model including local high-risk areas is first established, environmental loads are identified based on measured strain data, the overall boundary conditions are corrected using acceleration data, and the local model boundaries are then corrected secondary with strain data; then, the environmental load calculation formula is optimized in combination with wave meter test data, and a probabilistic prediction model that takes uncertainty into account is established through historical data; finally, the load boundary output by the model is input into the corrected model for fatigue analysis, thereby achieving a high-precision quantitative assessment of the accumulated damage and remaining life. Predicting the remaining life of the jacket-type offshore platform structure based on the identified loads is more accurate than the prediction method based on the empirical formula. And considering the impact of structural damage on the remaining fatigue life, the remaining life can always be predicted based on the current state of the structure. Compared with the non-destructive structure calculation accuracy based on the design stage, it is more accurate, more in line with the actual on-site engineering conditions, and improves the accuracy of the jacket platform life prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0046] Figure 1 A schematic flow chart of a method for assessing the remaining life of a jacket platform provided in this specification;

[0047] Figure 2 A schematic diagram of a jacket platform remaining life assessment device provided in this specification;

[0048] Figure 3 This is a schematic diagram of a computer device for implementing a method for assessing the remaining life of a jacket platform provided in this specification. DETAILED DESCRIPTION

[0049] To make the purpose, technical solutions, and advantages of this specification more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this specification and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0050] The following describes in detail the technical solutions provided by various embodiments of the present application in conjunction with the accompanying drawings.

[0051] Figure 1 The following is a flow chart of a method for assessing the remaining life of a jacket platform in this specification, which specifically includes the following steps:

[0052] S101: Establish a multi-fidelity digital model of the jacket platform structure; wherein the multi-fidelity digital model includes an overall finite element model and an overall digital model.

[0053] In this embodiment, the overall finite element model of the jacket platform structure is established, specifically including:

[0054] The beam188 unit was used to establish the finite element model of the pile legs, struts, chords, cross braces, and diagonal braces. The shell181 unit was used to establish the finite element model of the main deck, production deck, bottom deck, and spider deck. The combine39 nonlinear spring unit was used at the bottom of the pile legs to simulate the nonlinear boundary of the pile foundation inserted into the seabed, thus obtaining the finite element model of the bottom of the pile legs and the overall finite element model.

[0055] Determine the local finite element model of the jacket platform from the overall finite element model, including:

[0056] The long-term distribution of fatigue stress range is simulated by two-parameter Weibull distribution, and the allowable stress range method is used to perform simplified fatigue analysis on the overall finite element model to determine the local finite element model.

[0057] For example, a finite element model of the jacket structure was constructed using the general-purpose finite element software ANSYS. Beam188 elements were used to model the legs, struts, chords, cross braces, and diagonal braces, with the upper portion of the splash zone being modeled using beam188 elements. Deck structures, including the main deck, production deck, bottom deck, and spider deck, were modeled using shell181 elements. Bound contact was used between shell and beam elements to simulate the effect of stiffeners. A nonlinear spring combine39 element was connected to the bottom of each leg in the X, Y, and Z directions of the global coordinate system to describe the nonlinear boundary between the leg and the sea sand. The other end of the spring element was fully constrained.

[0058] In a specific embodiment, shear flow loads are applied to underwater structures according to different depths, wave force loads and wind loads are applied to the splash zone using the Morrison equation, and wind loads are applied to the structure above the splash zone. The wind loads are applied according to average wind and pulsating wind respectively.

[0059] Optionally, solid185 units are used to establish local digital models of various types of pipe nodes in local areas, and loads such as normal force, tangential force, and moment are applied to the end faces of the local digital models of various pipe nodes to calculate the maximum value of the stress concentration factor KT and generate a large number of training samples.

[0060] Based on the training samples, a response surface model between the end node displacement and the maximum stress concentration factor is established (that is, the local numerical model corresponding to the local finite element model).

[0061] Optionally, the ocean loads in the sampled working conditions can be applied to the multi-fidelity digital model to calculate the nominal stress and the nodal displacement of the local digital model end face, thereby generating a large number of training samples.

[0062] A first response surface model is established with ocean load as input parameter and local digital model end node displacement and nominal stress as output.

[0063] The actual local stress of the structure is calculated based on the first response surface model and the digital fitting model or the finite element local model. Based on the local stress time-varying curve combined with the SN curve, the Miner linear cumulative damage criterion is used to predict the remaining life of the local multi-fidelity digital model.

[0064] The server mentioned in this specification can be a server set up on a business platform, or a device such as a desktop computer or a laptop computer that can execute the solution of this specification. For the sake of convenience, the following description will only take the server as the execution subject.

[0065] S102: Determine a local finite element model of the jacket platform of particular interest from the overall finite element model, and identify the marine environmental load of the overall finite element model based on measured local strain response data of the local finite element model.

[0066] In this embodiment, based on the measured local strain response data of the local finite element model, the marine environmental load of the overall finite element model is identified, specifically including:

[0067] Perform stress analysis on the local finite element model to determine the load form of the local finite element model and decompose the load on the local finite element model in the nodal coordinate system;

[0068] Analyze the local finite element model under the action of the decomposed load alone to obtain the strain mode of the local finite element model under each load;

[0069] The strain sensor layout positions of the local finite element model are determined by combining the D optimization algorithm with the greedy algorithm, and sensors are installed at the strain sensor layout positions to obtain the measured local strain response data of the local finite element model;

[0070] According to the strain mode and measured local strain response data, the load coefficient matrix is ​​obtained by numerical method.

[0071] The external load matrix of the local finite element model is obtained by solving the load coefficient matrix;

[0072] Based on the external load matrix, the marine environmental load is derived.

[0073] For example, the loads acting on the local finite element model are decomposed in a nodal coordinate system: loads in the form of force rectangles are decomposed using a Cartesian coordinate system, while force loads are decomposed using a cylindrical coordinate system.

[0074] In a specific embodiment, the ocean environment load may be derived according to the external load matrix by: deducing the ocean environment load on the entire model according to the identified local model external load and the distribution relationship of wind load, wave load, and current load.

[0075] For example, the specific process of derivation can be:

[0076] 1) Understand the physical meaning of the external load matrix:

[0077] Through the previous steps (D optimization algorithm to determine sensor locations, measured strain responses, modal analysis and solution), the external load matrix (e.g., F_local) of the local finite element model is obtained. This matrix represents all external forces (or moments) applied to the key nodes of the local model during the identification time period. These forces are the effects of the actual marine environmental loads such as wind, waves, and currents acting on the structure in the local area.

[0078] 2) Establish load distribution relationship (key step):

[0079] This step is the foundation of the entire derivation. It requires prior knowledge or reasonable assumptions about the typical distribution patterns of wind, wave, and current loads across the entire structural space. These patterns are typically based on physical principles and empirical formulas.

[0080] Wind load distribution: Usually related to the windward area exposed to the wind, which may vary in height direction (such as the mean wind speed profile).

[0081] Wave load distribution: Complex and time-varying, primarily acting near and below the waterline. Typical distribution patterns may be based on wave theory (e.g., Morison equations, diffraction / radiation theory), showing a characteristic pressure decay with water depth (e.g., exponential decay).

[0082] Current load distribution: It mainly acts on the part below the waterline, and is usually based on equations similar to the Morison equation or simple resistance formulas. It is believed that the load is proportional to the square of the water flow, and the distribution along the water depth may be relatively uniform or have a gradient.

[0083] These load distribution patterns can be abstracted into a series of spatial distribution functions or basis functions, which describe the characteristics of each load type as it changes with position (x, y, z).

[0084] 3) Establish the relationship between local load and overall load distribution:

[0085] The external load matrix F_local of the local model contains information about the combined forces of wind, waves, and current in the local area. However, this external load matrix itself is a comprehensive reflection of the various environmental load components superimposed in space at the local node.

[0086] The goal of the derivation is to infer the wind, wave and current loads with spatial distribution characteristics that the entire structure is subjected to.

[0087] The basic idea is to regard the identified F_local as the projection or integration result of a known distribution pattern modulated by a set of unknown amplitude coefficients (such as C_wind, C_wave, C_current) on the local node.

[0088] 4) Extrapolate and solve for global load amplitude:

[0089] Using the distribution relationships and mathematical models established in step 2 (e.g., wind load on the entire structure = C_wind * f(wind distribution); wave load = C_wave * g(wave distribution); current load = C_current * h(current distribution)), calculate the load vector generated by each distribution mode on the entire structure.

[0090] Key Operation: Calculate the load vectors for these global distribution modes (e.g. F_local_wind_simulated, F_local_wave_simulated, F_local_current_simulated) at the nodes or sub-regions of the local model. This is equivalent to numerically integrating the distribution modes in the local region (finite element integration).

[0091] Assume that F_local is approximately equal to the linear combination of these local load vectors generated by the global distribution mode: F_local ≈ [F_local_wind_simulated | F_local_wave_simulated | F_local_current_simulated] * [C_wind; C_wave; C_current]. (Here [... | ... | ...] denotes the concatenation of matrices by column, and [C_wind; C_wave; C_current] is the coefficient vector).

[0092] This establishes a system of equations: measured local external load ≈ known local distributed load * unknown global load factor.

[0093] Numerical methods (such as the least squares method and optimization techniques) are used to solve this set of coefficients (C_wind, C_wave, C_current). These coefficients represent the equivalent intensity or main characteristic quantities of each environmental load (wind, wave, current) on the overall structure (such as the force coefficient related to the average wind speed, the force coefficient related to the significant wave height, and the force coefficient related to the average current velocity).

[0094] 5) Derivation of overall marine environmental loads:

[0095] Substitute the obtained load coefficients C_wind, C_wave, and C_current back into the overall load distribution model established in steps 2 and 3.

[0096] At this time, the overall wind load = C_wind * f (wind distribution), the overall wave load = C_wave * g (wave distribution), and the overall current load = C_current * h (current distribution).

[0097] In this way, the time history or equivalent description of the marine environmental loads such as wind, waves, and currents with spatial distribution characteristics that the entire (overall finite element model) structure is subjected to is obtained.

[0098] S103: Correcting the boundary conditions of the overall finite element model based on the measured acceleration data of the overall finite element model to obtain an overall corrected model.

[0099] In this embodiment, the boundary conditions of the overall finite element model are corrected based on the measured acceleration data of the overall finite element model to obtain the overall corrected model, specifically including:

[0100] Acquire measured acceleration data and perform preprocessing to obtain preprocessed measured acceleration data;

[0101] The random subspace method is used to calculate the modal parameters of the jacket platform structure and obtain the test mode;

[0102] Use ANSYS solver to solve the modes of the overall finite element model and obtain the calculated modes;

[0103] Based on the test mode, the parameters to be corrected are selected through sensitivity analysis, and the overall finite element model is corrected to obtain the overall corrected model; wherein, the convergence judgment condition of the correction is that the relative error between the test mode and the calculated mode is less than a first preset error threshold.

[0104] Optionally, the first preset error threshold may be 0.1% or 0.01%, and may be set according to actual needs, and is not specifically limited here.

[0105] In a specific embodiment, the modal of the overall finite element model is solved using the ANSYS solver to obtain the calculated modal. The calculated modal can be: a fixed constraint is applied to the lower spring unit of the overall structure finite element model of the jacket-type offshore platform, a gravity load is applied to the overall structure, and a modal analysis is performed using ANSYS software to obtain the main frequencies and vibration modes of the overall structure model of the jacket-type offshore platform to obtain the calculated modal.

[0106] Taking the main frequency of the experimental mode as the benchmark, the parameters with correction are selected from the physical parameters that have a greater impact on the main frequency calculation results through sensitivity analysis. After simulation calculation, it can be seen that the constraint has the greatest impact on the calculation results of the main frequency, so the stiffness coefficient of the spring unit fixed to the pile leg can be selected as the correction parameter.

[0107] S104: Correcting the local finite element correction model in the overall correction model based on the measured local strain response data to obtain a local correction model; wherein the local finite element correction model is obtained by correcting the boundary conditions of the local finite element model.

[0108] In this embodiment, the local finite element correction model in the overall correction model is corrected based on the measured local strain response data to obtain the local correction model, which specifically includes:

[0109] Acquiring strain sensor test data and performing preprocessing to obtain preprocessed strain sensor test data;

[0110] The local finite element modified model was calculated using the ANSYS solver to obtain the time-varying strain curve of the local finite element modified model under the action of marine environmental loads.

[0111] Based on the time-varying strain curve, the physical parameters to be corrected of the local finite element correction model are determined through sensitivity analysis and correction is performed to obtain the local correction model; wherein, the convergence judgment condition of the correction is that the relative error between the strain test value and the finite element calculation value is less than a second preset error threshold.

[0112] Optionally, the second preset error threshold may be 0.1% or 0.01%, and may be set according to actual needs, and is not specifically limited here.

[0113] In a specific embodiment, obtaining strain sensor test data and performing preprocessing can be as follows: for the overall finite element model of the jacket-type offshore platform, a fixed constraint is applied to the lower spring unit, a flow load is applied to the underwater structure portion of the upper overall structure in the form of a uniformly distributed force that varies with depth, a wind load is applied to the surface portion in the form of a uniformly distributed force, and a wave load is applied to the splash zone structure portion in the form of a uniformly distributed force and moment.

[0114] Optionally, the time-varying strain curve may be obtained by performing a dynamic analysis on the entire structure to obtain the time-varying strain curve of the local structure under the combined action of the ocean load.

[0115] Taking the time-varying strain curve as a benchmark, the parameters that have a greater impact on local strain are calculated through sensitivity analysis as the physical parameters to be corrected. The local model of the jacket-type offshore platform structure is corrected once. The convergence criterion is that the relative error between the strain test value and the finite element calculation value is less than 0.1%.

[0116] S105: Based on the local correction model and the time-varying curve of the ocean environmental load, combined with the measured local strain response data and the wave meter test data, the load parameters in the ocean environmental load calculation formula are corrected to obtain a corrected multi-fidelity digital model; wherein the wave meter test data is data obtained using a wave meter.

[0117] In this embodiment, based on the local correction model and the time-varying curve of the ocean environmental load, combined with the measured local strain response data and wave meter test data, the load parameters in the ocean environmental load calculation formula are corrected, specifically including:

[0118] Acquire and process wave meter test data to obtain the equivalent wave height time-varying curve;

[0119] Based on the measured local strain response data and the time-varying curve of equivalent wave height, the load parameters in the marine environmental load are corrected.

[0120] S106: Based on the historical load identification data, a load prediction model that takes into account the influence of uncertainty is established.

[0121] In this embodiment, based on historical load identification data, a load prediction model that takes uncertainty into account is established, specifically including:

[0122] A Gaussian regression model is established based on historical load identification data and embedded into the Morrison equation to obtain the load prediction model.

[0123] For example, a Gaussian regression model can be established based on historical test data of marine environmental loads such as wind, waves, and currents (i.e., historical load identification data), and the Morrison equation can be embedded to establish a prediction model for wind, wave, and current loads to obtain a load prediction model.

[0124] Optionally, the fatigue and corrosion damage of the jacket platform structure in the current state can be calculated based on the load prediction model and the empirical formulas for uniform corrosion and pitting corrosion, respectively, to obtain the state of the jacket platform structure in the current state. The remaining life of the jacket platform structure in the current state can then be predicted to obtain the remaining life of the jacket platform structure in the current state.

[0125]

[0126] Where, r (t) represents the corrosion rate function, mm / a; d ∞ Indicates the corrosion thickness limit, m; α Represents shape parameters, which are selected according to the specific conditions of the platform structure; η It represents the scale parameter, which is selected according to the specific situation of the platform structure; Indicates the time when platform corrosion begins, Indicates the design service life of the offshore platform, Indicates the current time point.

[0127] The long-term cumulative fatigue damage criterion can be expressed as follows:

[0128]

[0129] Where, Indicates cumulative fatigue damage; k Indicates the number of stress blocks; Indicates the i Number of stress cycles in a stress block; Indicates that the constant amplitude stress range The number of stress cycles under action until failure; Fatigue strength safety factor.

[0130] The long-term cumulative fatigue damage criterion should meet the following boundary conditions: .

[0131] Current fatigue damage It can be expressed as follows:

[0132]

[0133] Where, m Indicates the number of load cases for fatigue damage calculation during the service life of the structure; Indicates that the service period is i Fatigue damage of a certain calculation point in the structure under a certain working condition; Indicates the i The proportion of each working condition in the service life of the structure; Indicates the i The probability of a working condition occurring.

[0134] Subsequent cumulative fatigue damage to the platform structure It can be expressed as: .

[0135] The cumulative total damage calculation can be expressed as follows: .

[0136] S107: Using the output result of the load prediction model as the force boundary input, fatigue analysis is performed on the overall digital model in the modified multi-fidelity digital model to obtain the accumulated damage and calculate the remaining fatigue life.

[0137] For example, the current state of the offshore platform structure can be used as a new starting point for damage assessment, the output of the load prediction model can be used as the force boundary input, and fatigue analysis can be performed on the modified multi-fidelity digital model to obtain the cumulative damage. When the fatigue failure occurs, the structure can be considered to have occurred, and the remaining fatigue life under the current state can be obtained.

[0138] Optionally, in addition to calculating the accumulated damage to determine the remaining fatigue life of the current offshore platform structure, the residual strength safety factor of the current offshore platform structure can also be calculated to determine the residual capacity influence coefficient. Furthermore, the remaining fatigue life can be determined based on the minimum value of the accumulated fatigue damage and the residual capacity influence coefficient. When the accumulated fatigue damage is at its minimum value, the remaining fatigue life is determined based on the accumulated fatigue damage. When the residual capacity influence coefficient is at its minimum value, the remaining fatigue life is determined based on the residual capacity influence coefficient.

[0139] For example, the current state of the offshore platform structure can be used as a new starting point for damage assessment, and the extreme load of once in a hundred years can be used as the force boundary condition. The horizontal strength analysis of the modified multi-fidelity digital model can be performed, and the residual storage strength ratio of the structure can be calculated to obtain the residual strength safety factor. The residual capacity influence coefficient is obtained by dividing it with the structural reserve strength coefficient. If the residual capacity influence coefficient is not greater than 0.4 and is the minimum value of the cumulative fatigue damage and the residual capacity influence coefficient, it is considered that the jacket platform structure has a major safety hazard, that is, the residual fatigue life at the residual capacity strength level is short. The calculation process of the residual capacity strength safety factor can be as follows:

[0140]

[0141]

[0142]

[0143] Where, Indicates the reserve strength coefficient of the jacket platform structure; It indicates that the ultimate horizontal load of the damage-free platform structure can be obtained through ultimate strength analysis; Indicates the ultimate horizontal load of the jacket platform structure design; Indicates the residual reserve strength coefficient of the jacket platform structure; It indicates that the ultimate horizontal load of the current platform structure can be obtained through ultimate strength analysis; The residual capacity influence coefficient can be expressed as and Calculate the ratio of .

[0144] based on Figure 1 The present invention provides a method for assessing the remaining life of a jacket platform. The method proposes a method for identifying the marine environmental loads of the overall structure based on the strain test data of the local structure of the offshore platform. The remaining life prediction of the jacket offshore platform structure based on the identified load is more accurate than the prediction method based on the empirical formula.

[0145] The digital model in the remaining life prediction method proposed in the present invention can be continuously updated according to the test data of various sensors, taking into account the impact of structural damage on the remaining fatigue life. The remaining life can always be predicted based on the current state of the structure. Compared with the non-destructive structure calculation accuracy based on the design stage, it is more accurate and more in line with the actual on-site engineering conditions.

[0146] The present invention proposes a comprehensive online prediction method for the remaining life of an aging jacket-type offshore platform structure. Based on the comprehensive prediction of the residual strength ratio calculation and fatigue calculation results, the prediction results are more accurate and the factors considered are more comprehensive. Compared with traditional fatigue calculations, the established online prediction model greatly reduces the amount of calculation, while ensuring accuracy and improving calculation efficiency.

[0147] When applying the remaining life assessment method for jacket platforms provided in this manual, it is not necessary to Figure 1 The steps are executed in the order shown. The specific execution order of the steps can be determined according to needs and this manual does not limit this.

[0148] The above is a method for assessing the remaining life of a jacket platform provided in one or more embodiments of this specification. Based on the same idea, this specification also provides a corresponding device for assessing the remaining life of a jacket platform, such as Figure 2 shown.

[0149] Figure 2 A schematic diagram of a jacket platform remaining life assessment device provided for this specification includes:

[0150] The model building module 201 is specifically configured to establish a multi-fidelity digital model of the jacket platform structure, wherein the multi-fidelity digital model includes an overall finite element model and an overall digital model; determine a local finite element model of the jacket platform of particular interest from the overall finite element model; and identify the marine environmental loads of the overall finite element model based on measured local strain response data of the local finite element model;

[0151] The model correction module 202 is specifically configured to correct the boundary conditions of the overall finite element model based on the measured acceleration data of the overall finite element model to obtain an overall corrected model; correct the local finite element correction model in the overall corrected model based on the measured local strain response data to obtain a local corrected model; wherein the local finite element correction model is obtained by correcting the boundary conditions of the local finite element model; based on the local corrected model and the time-varying curve of the marine environmental load, combined with the measured local strain response data and the wave meter test data, correct the load parameters in the marine environmental load calculation formula to obtain a corrected multi-fidelity digital model; wherein the wave meter test data is data obtained using a wave meter;

[0152] The life prediction module 203 is specifically used to establish a load prediction model that takes into account the influence of uncertainty based on historical load identification data; use the output results of the load prediction model as the force boundary input, perform fatigue analysis on the overall digital model in the modified multi-fidelity digital model, obtain cumulative damage, and calculate the remaining fatigue life.

[0153] The specific definitions of the jacket platform remaining life assessment device can be found in the definitions of the jacket platform remaining life assessment method described above and will not be further elaborated here. Each module within the aforementioned jacket platform remaining life assessment device can be implemented in whole or in part via software, hardware, or a combination thereof. Each of these modules can be embedded in or independent of a processor within a computer device in hardware form, or stored in a computer device memory in software form, allowing the processor to invoke and execute the corresponding operations of each module.

[0154] This specification also provides a computer-readable storage medium, which stores a computer program that can be used to execute the above Figure 1 A method for assessing the remaining life of a jacket platform is provided.

[0155] This manual also provides Figure 3 The structural diagram of the computer equipment shown in FIG. Figure 3 At the hardware level, the computer device includes a processor, an internal bus, a network interface, a memory, and a non-volatile memory. Of course, it may also include other hardware required for the business. The processor reads the corresponding computer program from the non-volatile memory into the memory and then runs it to achieve the above Figure 1 A method for assessing the remaining life of a jacket platform is provided.

[0156] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the above-described method embodiments. Any reference to memory, storage, database, or other media used in the embodiments provided herein may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0157] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for assessing the remaining life of a jacket platform, characterized in that: include: Establish a multi-fidelity digital model of the jacket platform structure, where the multi-fidelity digital model includes an overall finite element model and an overall digital model; Determine the local finite element model of the jacket platform from the overall finite element model, and identify the marine environmental loads of the overall finite element model based on the measured local strain response data of the local finite element model; Based on the measured acceleration data of the overall finite element model, the boundary conditions of the overall finite element model are corrected to obtain the overall corrected model; The local finite element correction model in the overall correction model is corrected based on the measured local strain response data to obtain a local correction model; wherein the local finite element correction model is obtained by correcting the boundary conditions of the local finite element model; Based on the local correction model and the time-varying curve of the ocean environmental load, combined with the measured local strain response data and wave meter test data, the load parameters in the ocean environmental load calculation formula are corrected to obtain a corrected multi-fidelity digital model; among which the wave meter test data is data obtained using a wave meter; Based on historical load identification data, a load prediction model considering the impact of uncertainty is established; The output of the load prediction model is used as the force boundary input to perform fatigue analysis on the overall digital model in the modified multi-fidelity digital model to obtain the accumulated damage and calculate the remaining fatigue life. Acquire measured acceleration data and perform preprocessing to obtain preprocessed measured acceleration data; The random subspace method is used to calculate the modal parameters of the jacket platform structure and obtain the test mode; Use ANSYS solver to solve the modes of the overall finite element model and obtain the calculated modes; Based on the test mode, the parameters to be corrected are selected through sensitivity analysis, and the overall finite element model is corrected to obtain the overall corrected model; wherein, the convergence judgment condition of the correction is that the relative error between the test mode and the calculated mode is less than a first preset error threshold.

2. The method for assessing the remaining life of a jacket platform according to claim 1, wherein: Establish an overall finite element model of the jacket platform structure, including: The beam188 element was used to establish the finite element model of the pile legs, struts, chords, cross braces, and diagonal braces. The shell181 element was used to establish the finite element model of the main deck, production deck, bottom deck, and spider deck. The combine39 nonlinear spring element was used at the bottom of the pile legs to simulate the nonlinear boundary of the pile foundation inserted into the seabed. This resulted in a finite element model of the bottom of the pile legs and the overall finite element model. Determine the local finite element model of the jacket platform from the overall finite element model, including: The long-term distribution of fatigue stress range is simulated by two-parameter Weibull distribution, and the allowable stress range method is used to perform simplified fatigue analysis on the overall finite element model to determine the local finite element model.

3. The method for assessing the remaining life of a jacket platform according to claim 1, wherein: Based on the measured local strain response data of the local finite element model, the marine environmental loads of the overall finite element model are identified, including: Perform stress analysis on the local finite element model to determine the load form of the local finite element model and decompose the load on the local finite element model in the nodal coordinate system; Analyze the local finite element model under the action of the decomposed load alone to obtain the strain mode of the local finite element model under each load; The strain sensor layout positions of the local finite element model are determined by combining the D optimization algorithm with the greedy algorithm, and sensors are installed at the strain sensor layout positions to obtain the measured local strain response data of the local finite element model; According to the strain mode and measured local strain response data, the load coefficient matrix is ​​obtained by numerical method. The external load matrix of the local finite element model is obtained by solving the load coefficient matrix; Based on the external load matrix, the marine environmental load is derived.

4. The method for assessing the remaining life of a jacket platform according to claim 1, wherein: The local finite element correction model in the overall correction model is corrected based on the measured local strain response data to obtain the local correction model, specifically including: Acquiring strain sensor test data and performing preprocessing to obtain preprocessed strain sensor test data; The local finite element modified model was calculated using the ANSYS solver to obtain the time-varying strain curve of the local finite element modified model under the action of marine environmental loads. Based on the time-varying strain curve, the physical parameters to be corrected of the local finite element correction model are determined through sensitivity analysis and correction is performed to obtain the local correction model; wherein, the convergence judgment condition of the correction is that the relative error between the strain test value and the finite element calculation value is less than a second preset error threshold.

5. The method for assessing the remaining life of a jacket platform according to claim 1, wherein: Based on the local correction model and the time-varying curve of the ocean environmental load, combined with the measured local strain response data and wave meter test data, the load parameters in the ocean environmental load calculation formula are corrected, including: Acquire and process wave meter test data to obtain the equivalent wave height time-varying curve; Based on the measured local strain response data and the time-varying curve of equivalent wave height, the load parameters in the marine environmental load are corrected.

6. The method for assessing the remaining life of a jacket platform according to claim 1, wherein: Based on historical load identification data, a load prediction model that takes into account the impact of uncertainty is established, including: A Gaussian regression model is established based on historical load identification data and embedded into the Morrison equation to obtain the load prediction model.

7. A jacket platform remaining life assessment device, characterized in that: include: The model building module is specifically used to establish a multi-fidelity digital model of the jacket platform structure; the multi-fidelity digital model includes an overall finite element model and an overall digital model; a local finite element model of the jacket platform of particular interest is determined from the overall finite element model; and based on the measured local strain response data of the local finite element model, the marine environmental loads of the overall finite element model are identified; The model correction module is specifically used to correct the boundary conditions of the overall finite element model based on the measured acceleration data of the overall finite element model to obtain the overall corrected model; correct the local finite element correction model in the overall corrected model based on the measured local strain response data to obtain the local corrected model; wherein the local finite element correction model is obtained by correcting the boundary conditions of the local finite element model; based on the local corrected model and the time-varying curve of the marine environmental load, combined with the measured local strain response data and the wave meter test data, the load parameters in the marine environmental load calculation formula are corrected to obtain a corrected multi-fidelity digital model; wherein the wave meter test data is data obtained using a wave meter; The life prediction module is specifically used to establish a load prediction model that takes into account the influence of uncertainty based on historical load identification data. The output of the load prediction model is used as the force boundary input to perform fatigue analysis on the overall digital model in the modified multi-fidelity digital model to obtain the accumulated damage and calculate the remaining fatigue life. Acquire measured acceleration data and perform preprocessing to obtain preprocessed measured acceleration data; The random subspace method is used to calculate the modal parameters of the jacket platform structure and obtain the test mode; Use ANSYS solver to solve the modes of the overall finite element model and obtain the calculated modes; Based on the test mode, the parameters to be corrected are selected through sensitivity analysis, and the overall finite element model is corrected to obtain the overall corrected model; wherein, the convergence judgment condition of the correction is that the relative error between the test mode and the calculated mode is less than a first preset error threshold.

8. A computer-readable storage medium, characterized in that The storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

9. A computer device, characterized in that: The method comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method according to any one of claims 1 to 6 is implemented.

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