Method for analyzing fatigue life of tower footing of floating type wind-light-fish equipment

Abstract

The invention provides a tower footing fatigue life analysis method for floating type wind-light-fish equipment, which comprises the following steps of: acquiring wind wave parameters and tower footing parameters of a place where the wind-light-fish equipment is to be put, and constructing a tower footing stress time history of the wind-light-fish equipment; substituting the tower footing stress time history into a rain flow algorithm to obtain equivalent stress amplitude; according to the equivalent stress amplitude, the number of times of bearable cyclic action of the tower footing is determined; and substituting the bearable cycle action times of the tower footing into the linear fatigue accumulated damage model to obtain the fatigue life of the tower footing. According to the tower footing fatigue life analysis method of the floating type wind-light-fishing equipment, the durability and the service life of the tower footing structure of the floating type wind-light-fishing equipment can be predicted in a complex marine environment, and safe and stable operation of the equipment is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of design and safety assessment of offshore floating structures, and in particular relates to a tower base fatigue life analysis method for floating wind, light and fishing equipment. Background Art

[0002] In the overall structure of the floating wind, solar and fishing equipment, the tower base, as the supporting structure of the entire equipment, not only bears the weight of the upper wind turbines, solar photovoltaic panels and fishery breeding facilities, but also needs to maintain sufficient stability and durability in the complex and changeable marine environment.

[0003] However, in actual applications, the marine environment in which floating wind and light fishing equipment is located is often very harsh. Due to the randomness and uncertainty of wind and waves, the tower base is very likely to become the area with the most concentrated stress in the entire equipment under the action of long-term dynamic loads, which will not only accelerate the fatigue damage process of the tower base material, but also may lead to a gradual decrease in structural strength, and then cause serious safety accidents, such as equipment overturning, breakage, etc.; which will in turn affect the service life of the entire equipment and seriously affect the economic benefits of energy production and fishery farming. Summary of the invention

[0004] The present invention is based on the inventor's discovery and understanding of the following facts and problems:

[0005] In floating wind and solar fishing equipment, the tower base not only bears the weight of the wind turbine rotor and solar panels, but also plays a key role in stabilizing the entire equipment in the complex and changing marine environment. The length of its fatigue life is directly related to whether the equipment can operate continuously and stably under harsh natural conditions, thereby ensuring efficient energy conversion and smooth fishery production.

[0006] Under the continuous action of random wind and waves, the floating structure as a whole will be affected by a variety of dynamic loads such as wind, waves and possible ocean currents. These loads are not only unpredictable, but also often have large amplitudes and frequencies, which pose a severe challenge to the structural strength of the equipment. In particular, under the effect of wind shear, the wind speed gradually increases with the increase in height, so that the wind turbine rotor located at high altitude needs to withstand huge wind loads that far exceed the ground wind speed. These wind loads are transmitted to the tower base through the tower structure and produce a significant bending moment effect at the bottom of the tower, causing the tower base to become the area with the highest stress level in the entire equipment. This stress concentration phenomenon not only increases the risk of fatigue damage at the tower base, but may also cause its bearing capacity to decrease, thereby threatening the safety and stability of the entire equipment.

[0007] In addition, the high-frequency starting load generated by the wind turbine rotor during rotation is also one of the important factors affecting the fatigue life of the tower base. This effect will produce a severe impact load on the tower base in a short period of time, causing it to be subjected to additional dynamic stress. This stress effect is superimposed on the bending moment effect generated by the wind load, further exacerbating the risk of fatigue damage to the tower base. Over a long period of time, the fatigue accumulation of the tower base will gradually accumulate, eventually leading to a significant shortening of its fatigue life, and may even cause structural failure, posing a serious threat to the safe operation of the equipment.

[0008] To this end, an embodiment of the present invention proposes a tower base fatigue life analysis method for floating wind and solar fishing equipment, which includes the following steps:

[0009] Obtain the wind and wave parameters and tower foundation parameters of the site where the wind and light fishing equipment is to be deployed, and construct the tower foundation stress time history of the wind and light fishing equipment;

[0010] Substituting the tower foundation stress time history into the rain flow algorithm to obtain the equivalent stress amplitude;

[0011] According to the equivalent stress amplitude, determine the number of cyclic actions that the tower foundation can withstand;

[0012] The number of cyclic actions that the tower foundation can withstand is substituted into a linear fatigue cumulative damage model to obtain the fatigue life of the tower foundation.

[0013] In summary, the tower base fatigue life analysis method of the floating wind-powered fishing equipment provided in the embodiment of the present invention can predict the durability and service life of the tower base structure of the floating wind-powered fishing equipment in a complex marine environment, thereby ensuring the safe and stable operation of the equipment.

[0014] In some embodiments, the step of obtaining wind and wave parameters and tower foundation parameters of the site where the wind and light fishing equipment is to be deployed, and constructing the tower foundation stress time history of the wind and light fishing equipment includes:

[0015] Obtain wind and wave parameters and tower base parameters of the site where the wind and light fishing equipment is to be deployed;

[0016] Substituting the wind and wave parameters and tower foundation parameters into a preset bending moment transport model to obtain a tower foundation bending moment time history under the i-th working condition;

[0017] Substitute the tower foundation bending moment time history into the stress calculation model to obtain the tower foundation stress time history of the wind and light fishing equipment.

[0018] In some embodiments, the tower foundation parameters include the tower foundation section inertia moment and the tower foundation diameter; the tower foundation stress time history formula is provided in the stress calculation model:

[0019]

[0020] Where: I tower is the moment of inertia of the tower base section; Dtower is the tower base diameter; M i (t) is the time history of the tower foundation bending moment under the i-th working condition.

[0021] In some embodiments, the step of substituting the tower foundation stress time history into a rain flow algorithm to obtain an equivalent stress amplitude comprises:

[0022] Substituting the tower foundation stress time history into the rain flow algorithm to obtain the number of stress cycles, the amplitude corresponding to each stress cycle and the average value;

[0023] Constructing a rain flow matrix according to the number of stress cycles, the amplitude and the average value corresponding to each stress cycle;

[0024] According to the rain flow matrix, the occurrence probability of each stress cycle amplitude is obtained;

[0025] The equivalent stress amplitude is calculated according to the stress amplitude and the probability of occurrence of the stress amplitude.

[0026] In some embodiments, the number of cycles that the tower foundation can withstand includes the number of cycles that the tower foundation can withstand in the crack initiation stage and the number of cycles that the tower foundation can withstand in the crack extension stage;

[0027] The step of determining the number of cyclic actions that the tower foundation can withstand according to the equivalent stress amplitude comprises:

[0028] Substituting the equivalent stress amplitude into the fatigue-life model, the number of cycles that the tower foundation can withstand in the crack initiation stage is obtained;

[0029] Obtaining a preset initial crack length and a preset critical crack length;

[0030] Substituting the initial crack length and the critical crack length into the crack library extension model, the number of cyclic actions that the tower foundation can withstand during the crack extension stage is obtained.

[0031] In some embodiments, the fatigue life of the tower foundation includes the fatigue life of the tower foundation in the crack initiation stage and the fatigue life of the tower foundation in the crack extension stage;

[0032] The step of substituting the number of cyclic actions that the tower foundation can withstand into a linear fatigue cumulative damage model to obtain the fatigue life of the tower foundation includes:

[0033] Substitute the number of cycles that the tower foundation can withstand at the crack initiation stage into the fatigue life calculation model to obtain the fatigue life of the tower foundation at the crack initiation stage;

[0034] Substitute the number of cycles that the tower foundation can withstand during the crack propagation stage into the fatigue life calculation model to obtain the fatigue life of the tower foundation during the crack propagation stage.

[0035] The fatigue life of the tower foundation in the crack initiation stage and the fatigue life of the tower foundation in the crack extension stage are superimposed to obtain the fatigue life of the tower foundation.

[0036] In some embodiments, the fatigue-life model has a formula:

[0037]

[0038] Where: N i A is the number of cycles that the tower foundation can withstand during the crack initiation stage; f is the material parameter of the tower base; S reff is the equivalent stress amplitude;

[0039] And / or, the crack library growth model is provided with a formula:

[0040]

[0041] Where: N ic is the number of cycles that the tower foundation can withstand during the crack expansion stage; G is the crack growth rate coefficient; a d is the initial crack length; a c is the critical crack length; S reff is the equivalent stress amplitude; m f is the material constant.

[0042] In some embodiments, the fatigue life calculation model is provided with a formula:

[0043]

[0044] Where: FL i The unit is year; T0 is the simulation time, and the unit of T0 is hour; N0 is the number of stress cycles within T0, and N is the number of cycles that the tower base can withstand.

[0045] In some embodiments, if there are n working conditions acting on the wind-light fishing device throughout the year, the probability of the occurrence of the i-th working condition is P i , the working condition includes wind speed; then the fatigue life calculation model also has a formula:

[0046]

[0047] Where: D i =1FL i .

[0048] In some embodiments, the steps include:

[0049] Obtain the annual average wind speed of the site where the wind and light fishing equipment is to be deployed, and construct a wind speed probability density function curve;

[0050] The wind speed probability density function curve is divided into i intervals, i>0;

[0051] The median of the ith interval is set as the wind speed U at the reference height, and the area enclosed by the ith small interval and the wind speed probability density function curve is set as the probability P of wind speed U occurring in one year. i . BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a flow chart of a tower base fatigue life analysis method of a floating wind-light fishing equipment provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0054] like Figure 1 As shown, an embodiment of the present invention provides a tower base fatigue life analysis method for floating wind and light fishing equipment, which includes the following steps:

[0055] S10, obtain the wind and wave parameters and tower base parameters of the site where the wind and light fishing equipment is to be deployed, and construct the tower base stress time history of the wind and light fishing equipment. That is, it is necessary to obtain the wind and wave parameters of the scheduled deployment site of the wind and light fishing equipment, which include but are not limited to key marine meteorological data such as wind speed distribution, wave height, period and direction. At the same time, accurately measure and record the geometric parameters of the tower base structure such as the tower base section inertia moment and tower base diameter; then construct the tower base stress time history curve of the floating wind and light fishing equipment tower base in the real marine environment, which can dynamically reflect the stress state of the tower base structure changing with time.

[0056] S20, substituting the tower foundation stress time history into the rain flow algorithm to obtain an equivalent stress pair. The tower foundation stress time history data obtained in the previous step is input into the rain flow algorithm. The rain flow algorithm is a data processing technology widely used in fatigue analysis, which can effectively extract stress-strain cycles from complex stress-time history and calculate the equivalent stress amplitude of each cycle.

[0057] S30, determining the number of cycles that the tower foundation can withstand based on the equivalent stress amplitude. That is, based on the fatigue characteristic curve of the tower foundation material, that is, the relationship between the stress amplitude and the number of cycles that can be sustained, combined with the equivalent stress amplitude obtained in step S20, determine the number of cycles that the tower foundation can safely withstand under a given stress level.

[0058] S40, substitute the number of cycles that the tower base can withstand into the linear fatigue cumulative damage model to obtain the fatigue life of the tower base. That is, substitute the number of cycles that the tower base can withstand into the linear fatigue cumulative damage model. This model assumes that fatigue damage is linearly cumulative, that is, each stress cycle will cause a certain amount of damage to the structure. When the cumulative damage reaches a certain critical value, fatigue failure occurs in the structure. Through calculation, the fatigue life of the tower base under the expected use conditions can be obtained, that is, the total time or number of cycles required from the initial state to reach the fatigue failure point, which provides a scientific basis for equipment maintenance plans, replacement strategies and long-term safe operation.

[0059] In summary, the tower base fatigue life analysis method of the floating wind and fishing equipment provided in the embodiment of the present invention can predict the durability and service life of the tower base structure of the floating wind and fishing equipment in a complex marine environment, thereby ensuring the safe and stable operation of the equipment.

[0060] In some embodiments, step S10 obtains wind and wave parameters and tower foundation parameters of the site where the wind and light fishing equipment is to be deployed, and constructs the tower foundation stress time history of the wind and light fishing equipment, including:

[0061] Obtain wind and wave parameters and tower base parameters of the site where the wind and light fishing equipment is to be deployed;

[0062] Substituting the wind and wave parameters and tower foundation parameters into a preset bending moment transport model to obtain a tower foundation bending moment time history under the i-th working condition;

[0063] Substitute the tower foundation bending moment time history into the stress calculation model to obtain the tower foundation stress time history of the wind and light fishing equipment.

[0064] In other words, by dividing the wind and wave parameters into multiple working conditions, analyzing the tower foundation bending moment time history under different working conditions, and then calculating the tower foundation stress time history of the wind, light and fishing equipment, we can comprehensively analyze the stress conditions of the tower foundation under different environments and dynamically reflect the stress state of the tower foundation structure at different time points. The results of this step provide key data support for subsequent fatigue life prediction.

[0065] The tower foundation parameters include the tower foundation section inertia moment and tower foundation diameter; the tower foundation stress time history formula is provided in the stress calculation model:

[0066]

[0067] Where: I tower is the moment of inertia of the tower base section; D tower is the tower base diameter; M i (t) is the time history of the tower foundation bending moment under the i-th working condition.

[0068] In some embodiments, the step of substituting the tower foundation stress time history into a rain flow algorithm to obtain an equivalent stress amplitude comprises:

[0069] Substituting the tower foundation stress time history into the rain flow algorithm to obtain the number of stress cycles, the amplitude corresponding to each stress cycle and the average value;

[0070] Constructing a rain flow matrix according to the number of stress cycles, the amplitude and the average value corresponding to each stress cycle;

[0071] According to the rain flow matrix, the occurrence probability of each stress cycle amplitude is obtained;

[0072] The equivalent stress amplitude is calculated according to the stress amplitude and the probability of occurrence of the stress amplitude.

[0073] Specifically, the previously calculated tower foundation stress time history data is used as input and processed by the Rainflow algorithm. The Rainflow algorithm is an effective tool for extracting stress-strain cycles from complex stress-time histories. It can identify and record the start and end points of each stress cycle, as well as the amplitude and average value of each cycle. In this step, the Rainflow algorithm traverses the entire stress time history data and extracts the number of all stress cycles, as well as the amplitude and average value corresponding to each cycle.

[0074] Next, a rainflow matrix is ​​constructed based on the number of extracted stress cycles, the amplitude and average value corresponding to each cycle. This matrix records the detailed information of all stress cycles with the amplitude of the stress cycle as the row and the order or time of the cycle as the column.

[0075] Then, according to the constructed rain flow matrix, the probability of occurrence of each stress cycle amplitude is calculated. This step is obtained by counting the number of times each amplitude appears in the rain flow matrix and then dividing it by the total number of cycles, which helps to understand the proportion of stress cycles of different amplitudes in the overall stress history.

[0076] Finally, the equivalent stress amplitude is calculated based on the calculated stress amplitude and its corresponding occurrence probability. The equivalent stress amplitude is an indicator that can reflect the degree of fatigue damage accumulation of the tower foundation structure under complex stress history. It obtains a single stress value by weighted summing stress cycles of different amplitudes according to their occurrence probability and corresponding damage contribution, which is used for subsequent fatigue life prediction.

[0077] The calculation formula of the effective force amplitude is:

[0078]

[0079] Where: S reff is the equivalent stress amplitude; S rk is the kth stress cycle amplitude; f k For S rk Probability of occurrence.

[0080] In some embodiments, the number of cycles that the tower foundation can withstand includes the number of cycles that the tower foundation can withstand in the crack initiation stage and the number of cycles that the tower foundation can withstand in the crack extension stage;

[0081] In some embodiments, the step of determining the number of cyclic actions that the tower foundation can withstand based on the equivalent stress amplitude comprises:

[0082] Substituting the equivalent stress amplitude into the fatigue-life model, the number of cycles that the tower foundation can withstand in the crack initiation stage is obtained;

[0083] Obtaining a preset initial crack length and a preset critical crack length;

[0084] Substituting the initial crack length and the critical crack length into the crack library extension model, the number of cyclic actions that the tower foundation can withstand during the crack extension stage is obtained.

[0085] Specifically, first, the equivalent stress amplitude calculated previously is used as input and substituted into the fatigue-life model. The fatigue-life model contains a mathematical expression based on the mechanical properties of the material and the stress-strain relationship, which can predict the number of cycles that the structure can safely withstand at a given stress level. In this step, the fatigue-life model takes into account the fatigue characteristic curve (SN curve) of the tower base material and the size of the equivalent stress amplitude, and calculates the number of cycles that the tower base can withstand during the crack initiation stage. This value reflects the ability of the tower base structure to resist fatigue damage in the initial stage.

[0086] Next, in order to evaluate the fatigue life of the tower foundation during the crack propagation stage, it is necessary to obtain the preset initial crack length and the preset critical crack length. The initial crack length is usually determined based on the quality control during the manufacturing and installation of the tower foundation structure, while the critical crack length is set based on the fracture mechanics properties of the tower foundation material and the safety requirements of the structure. These two parameters are key inputs to the crack propagation model.

[0087] Then, the initial crack length and critical crack length are substituted into the crack growth model. The crack growth model is a mathematical model that describes the gradual growth of cracks under stress. It can predict the number of cycles that the structure can withstand during the crack growth stage. In this step, the crack growth model takes into account factors such as the crack growth rate, the fracture toughness of the material, and the stress level, and calculates the number of cycles that the tower foundation can withstand during the crack growth stage. This value reflects the ability of the tower foundation structure to continue to resist fatigue damage after the crack appears.

[0088] The fatigue-life model has a formula:

[0089]

[0090] Where: N i A is the number of cycles that the tower foundation can withstand during the crack initiation stage; f is the material parameter of the tower base; S reff is the equivalent stress amplitude.

[0091] Furthermore, the crack library extension model is provided with a formula:

[0092]

[0093] Where: N ic is the number of cycles that the tower foundation can withstand during the crack expansion stage; G is the crack growth rate coefficient; a d is the initial crack length; a c is the critical crack length; S reff is the equivalent stress amplitude; m f is the material constant.

[0094] In some embodiments, the fatigue life of the tower foundation includes the fatigue life of the tower foundation in the crack initiation stage and the fatigue life of the tower foundation in the crack extension stage;

[0095] The step of substituting the number of cyclic actions that the tower foundation can withstand into a linear fatigue cumulative damage model to obtain the fatigue life of the tower foundation includes:

[0096] Substitute the number of cycles that the tower foundation can withstand at the crack initiation stage into the fatigue life calculation model to obtain the fatigue life of the tower foundation at the crack initiation stage;

[0097] Substitute the number of cycles that the tower foundation can withstand during the crack propagation stage into the fatigue life calculation model to obtain the fatigue life of the tower foundation during the crack propagation stage.

[0098] The fatigue life of the tower foundation in the crack initiation stage and the fatigue life of the tower foundation in the crack extension stage are superimposed to obtain the fatigue life of the tower foundation.

[0099] In this embodiment, the number of cycles that the tower foundation can withstand, which was previously calculated at the crack initiation stage, is substituted into the fatigue life calculation model. This model is usually constructed based on the fatigue cumulative damage theory, which can predict the number of cycles required for the structure to reach fatigue failure at a given stress level. Through this step, we can obtain the fatigue life of the tower foundation at the crack initiation stage, that is, the time or number of cycles required for the tower foundation to resist fatigue damage in the initial stage and reach fatigue failure.

[0100] We then substituted the number of cycles that the tower foundation could withstand, which we calculated earlier during the crack propagation phase, into the same fatigue life calculation model. The purpose of this step is to estimate the time or number of cycles required for the tower foundation to continue to withstand cyclic loads and reach final failure after the crack appears. By considering factors such as the crack propagation rate, the fracture toughness of the material, and the stress level, we can derive the fatigue life of the tower foundation during the crack propagation phase.

[0101] Finally, we superimpose the fatigue life of the freehub during the crack initiation stage and the crack propagation stage to obtain the total fatigue life of the freehub. This step is to add the fatigue life of the two stages to obtain a single indicator that reflects the overall fatigue performance of the freehub.

[0102] Furthermore, the fatigue life calculation model is provided with a formula:

[0103]

[0104] Where: FL i The unit is year; T0 is the simulation time, and the unit of T0 is hour; N0 is the number of stress cycles within T0, and N is the number of cycles that the tower base can withstand.

[0105] Furthermore, if there are n working conditions acting on the wind-solar fishing equipment throughout the year, the probability of the occurrence of the i-th working condition is P i , the working condition includes wind speed; then the fatigue life calculation model also has a formula:

[0106]

[0107] Where: D i =1FL i .

[0108] In some embodiments, the tower base fatigue life analysis method of the floating wind and light fishing equipment further includes the steps of:

[0109] Obtain the annual average wind speed of the site where the wind and light fishing equipment is to be deployed, and construct a wind speed probability density function curve;

[0110] The wind speed probability density function curve is divided into i intervals, i>0;

[0111] The median of the ith interval is set as the wind speed U at the reference height, and the area enclosed by the ith small interval and the wind speed probability density function curve is set as the probability P of wind speed U occurring in one year. i .

[0112] In this embodiment, the annual average wind speed of the wind and light fishing equipment to be deployed is the basis for the subsequent construction of the wind speed probability density function curve, which reflects the overall level and distribution of wind speed in the area. We can accurately obtain this data by consulting historical meteorological data, real-time monitoring data or using professional meteorological forecast models.

[0113] Next, we construct a wind speed probability density function curve. This curve describes the probability density of wind speed under different wind speeds. Through this curve, we can intuitively understand the distribution of wind speed in the area, including the concentrated area of ​​wind speed, the degree of dispersion, and the probability of occurrence of extreme wind speeds. The method of constructing a wind speed probability density function curve usually includes parameter estimation and non-parametric estimation.

[0114] Then, we divide the constructed wind speed probability density function curve into i intervals, where i is an integer greater than 0. The purpose of this step is to discretize the continuous wind speed distribution into a series of wind speed intervals for subsequent analysis and calculation. The division of intervals can be determined according to actual needs and accuracy requirements, usually considering factors such as the degree of wind speed discreteness, the purpose of analysis, and the limitation of computing resources.

[0115] After dividing the intervals, we set the median of the ith interval as the wind speed U at the reference height. This step is to determine the specific wind speed value represented by each interval, so as to facilitate the subsequent connection between the wind speed and the fatigue life of the tower foundation. The reference height is usually determined based on factors such as the height of the tower foundation, the diameter of the wind rotor, and the measurement height of the meteorological data.

[0116] Finally, we calculate the area enclosed by the i-th small interval and the wind speed probability density function curve, which represents the probability of wind speed U occurring within a year. Each small interval corresponds to a working condition, and the probability of the wind speed occurring is also the probability of the working condition occurring.

[0117] Various embodiments of the methods described above herein may be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include: being implemented in one or more computer programs, which may be executed and / or interpreted on a programmable system including at least one programmable processing module, which may be a dedicated or general programmable processing module, which may receive data and instructions from a storage module, at least one input device, and at least one output device, and transmit data and instructions to the storage module, the at least one input device, and the at least one output device.

[0118] The program code for implementing the method itself can be written in any combination of one or more programming languages. These program codes can be provided to a processing module or control unit of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code, when executed by the processing module or control unit, causes the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code can be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0119] To provide interaction with a user, the methods described herein may be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0120] The methods described herein may be implemented in a computing system that includes a backend component (e.g., as a data server), or a computing system that includes a middleware component (e.g., an application server), or a computing system that includes a frontend component (e.g., a user computer with a graphical user interface or a grid browser through which a user can interact with an implementation of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication grid). Examples of communication grids include: a local area network (LAN), a wide area network (WAN), the Internet, and a blockchain grid.

[0121] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication grid. The relationship between the client and the server is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services ("Virtual Private Server", or "VPS" for short). The server may also be a server for a distributed system, or a server combined with a blockchain.

[0122] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0123] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0124] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0125] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, apparatus or device (such as a computer-based system, a system including a processing module, or other system that can fetch instructions from an instruction execution system, apparatus or device and execute instructions), or used in combination with these instruction execution systems, apparatuses or devices.

[0126] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a storage module and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0127] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0128] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0129] The storage medium mentioned above may be a read-only storage unit, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0130] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0131] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A tower base fatigue life analysis method for floating wind and light fishing equipment, characterized in that: The steps include: Obtain the wind and wave parameters and tower foundation parameters of the site where the wind and light fishing equipment is to be deployed, and construct the tower foundation stress time history of the wind and light fishing equipment; Substituting the tower foundation stress time history into the rain flow algorithm to obtain the equivalent stress amplitude; According to the equivalent stress amplitude, determine the number of cyclic actions that the tower foundation can withstand; The number of cyclic actions that the tower foundation can withstand is substituted into a linear fatigue cumulative damage model to obtain the fatigue life of the tower foundation.

2. The tower base fatigue life analysis method of floating wind and light fishing equipment according to claim 1 is characterized in that: The steps of obtaining the wind and wave parameters and tower foundation parameters of the site where the wind and light fishing equipment is to be deployed, and constructing the tower foundation stress time history of the wind and light fishing equipment include: Obtain wind and wave parameters and tower base parameters of the site where the wind and light fishing equipment is to be deployed; Substituting the wind and wave parameters and tower foundation parameters into a preset bending moment transport model to obtain a tower foundation bending moment time history under the i-th working condition; Substitute the tower foundation bending moment time history into the stress calculation model to obtain the tower foundation stress time history of the wind and light fishing equipment.

3. The tower base fatigue life analysis method of floating wind and light fishing equipment according to claim 2 is characterized in that: The tower foundation parameters include the tower foundation section inertia moment and tower foundation diameter; the tower foundation stress time history formula is provided in the stress calculation model: Where: I tower is the moment of inertia of the tower base section; D tower is the tower base diameter; M i (t) is the time history of the tower foundation bending moment under the i-th working condition.

4. The tower base fatigue life analysis method of floating wind and light fishing equipment according to claim 1 is characterized in that: Step 1: Substituting the tower foundation stress time history into the rain flow algorithm to obtain the equivalent stress amplitude includes: Substituting the tower foundation stress time history into the rain flow algorithm to obtain the number of stress cycles, the amplitude corresponding to each stress cycle and the average value; Constructing a rain flow matrix according to the number of stress cycles, the amplitude and the average value corresponding to each stress cycle; According to the rain flow matrix, the occurrence probability of each stress cycle amplitude is obtained; The equivalent stress amplitude is calculated according to the stress amplitude and the probability of occurrence of the stress amplitude.

5. The tower base fatigue life analysis method of floating wind and light fishing equipment according to claim 1 is characterized in that: The number of cycles that the tower foundation can withstand includes the number of cycles that the tower foundation can withstand in the crack initiation stage and the number of cycles that the tower foundation can withstand in the crack expansion stage; The step of determining the number of cycles that the tower foundation can withstand according to the equivalent stress amplitude includes: Substituting the equivalent stress amplitude into the fatigue-life model, the number of cycles that the tower foundation can withstand in the crack initiation stage is obtained; Obtaining a preset initial crack length and a preset critical crack length; Substituting the initial crack length and the critical crack length into the crack library extension model, the number of cyclic actions that the tower foundation can withstand during the crack extension stage is obtained.

6. The tower base fatigue life analysis method of floating wind and light fishing equipment according to claim 5 is characterized in that: The fatigue life of the tower foundation includes the fatigue life of the tower foundation in the crack initiation stage and the fatigue life of the tower foundation in the crack extension stage; The step of substituting the number of cyclic actions that the tower foundation can withstand into a linear fatigue cumulative damage model to obtain the fatigue life of the tower foundation includes: Substitute the number of cycles that the tower foundation can withstand at the crack initiation stage into the fatigue life calculation model to obtain the fatigue life of the tower foundation at the crack initiation stage; Substitute the number of cycles that the tower foundation can withstand during the crack propagation stage into the fatigue life calculation model to obtain the fatigue life of the tower foundation during the crack propagation stage. The fatigue life of the tower foundation in the crack initiation stage and the fatigue life of the tower foundation in the crack extension stage are superimposed to obtain the fatigue life of the tower foundation.

7. The tower base fatigue life analysis method of floating wind and light fishing equipment according to claim 5 is characterized in that: The fatigue-life model has the formula: Where: N i A is the number of cycles that the tower foundation can withstand during the crack initiation stage; f is the material parameter of the tower base; S reff is the equivalent stress amplitude; And / or, the crack library growth model is provided with a formula: Where: N ic is the number of cycles that the tower foundation can withstand during the crack expansion stage; G is the crack growth rate coefficient; a d is the initial crack length; a c is the critical crack length; S reff is the equivalent stress amplitude; m f is the material constant.

8. The tower base fatigue life analysis method of floating wind and light fishing equipment according to claim 6 is characterized in that: The fatigue life calculation model has a formula: Where: FL i The unit is year; T0 is the simulation time, and the unit of T0 is hour; N0 is the number of stress cycles within T0, and N is the number of cycles that the tower base can withstand.

9. The tower base fatigue life analysis method of floating wind and light fishing equipment according to claim 8 is characterized in that: If there are n working conditions acting on the wind and solar fishing equipment throughout the year, the probability of the occurrence of the i-th working condition is P i , the working condition includes wind speed; then the fatigue life calculation model also has a formula: Where: D i =1FL i .

10. The tower base fatigue life analysis method of floating wind and light fishing equipment according to claim 9 is characterized in that: Also includes the steps: Obtain the annual average wind speed of the site where the wind and light fishing equipment is to be deployed, and construct a wind speed probability density function curve; The wind speed probability density function curve is divided into i intervals, i>0; The median of the ith interval is set as the wind speed U at the reference height, and the area enclosed by the ith small interval and the wind speed probability density function curve is set as the probability P of wind speed U occurring in one year. i .

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