Ocean truss type net cage structure stress fatigue evaluation method, device and equipment and storage medium

Abstract

The invention discloses an ocean truss type net cage structure stress fatigue evaluation method, device and equipment and a storage medium, and relates to the technical field of ocean engineering and structural mechanics, and the method comprises the steps: obtaining net cage structure load information and assembly matrix set information; static and dynamic coupling analysis is carried out based on the net cage structure load information and the assembly matrix set information, the total displacement of the net cage is determined, and the static and dynamic coupling analysis comprises net cage static analysis and net cage dynamic analysis; and calculating the stress of the net cage structure according to the total displacement of the net cage and the assembly matrix set information, and predicting the fatigue life of the net cage to complete the stress fatigue evaluation of the net cage structure. The total displacement of the net cage is calculated by combining static analysis and dynamic analysis of the net cage, and the structural stress of the net cage is calculated, so that the fatigue life of the net cage is predicted, the net cage performance is evaluated, the stress state of the net cage under complex working conditions is efficiently and accurately solved, fatigue weak rods are recognized in advance for optimization, and the service life of the net cage is remarkably prolonged.

Description

Technical Field

[0001] This application relates to the technical field of ocean engineering and structural mechanics, and particularly to a method, device, equipment and storage medium for fatigue assessment of the force on an ocean truss cage structure. Background Art

[0002] Ocean truss cages are the core equipment for deep - sea aquaculture, with advantages such as strong wave - and - wind resistance, large aquaculture capacity, and environmental friendliness. With the rapid development of the global ocean economy, deep - sea aquaculture has become an important way to solve the problems of land resource shortage and food safety. However, the complexity of the ocean environment poses a severe challenge to the structural design of cages. During the long - term service of the cage structure, it will be repeatedly affected by dynamic loads, resulting in the accumulation of material fatigue and ultimately may lead to structural failure. Therefore, accurately evaluating the fatigue life of the force on an ocean truss cage structure is of great significance for ensuring its safe operation, reducing maintenance costs, and extending its service life.

[0003] Currently, in the existing practices, the structural analysis of ocean truss cages mainly relies on simplified models and empirical formulas for analysis, or on some commercial finite - element analysis software such as ANSYS, ABAQUS, etc., which can provide a preliminary estimate of the structural force to a certain extent.

[0004] However, in the face of complex loads, complex boundary conditions, and material properties such as dynamic loads like wave forces, current forces, and wind forces, elastic supports, inclined supports, and the corrosion and fatigue effects of materials in the ocean environment, the existing practices are difficult to accurately reflect the actual force state and fatigue life of the cage structure. Moreover, the software in the existing practices is usually complex in function and high in learning cost, making it difficult to carry out customized development for the special needs of ocean truss cages. For specialized analysis tools in the field of ocean engineering, especially those that support elastic supports, inclined supports, and dynamic loads, they are still relatively scarce and cannot accurately solve the force and fatigue life of ocean truss cage structures under actual working conditions. Therefore, how to more efficiently and accurately solve the force on an ocean truss cage structure for fatigue assessment of the cage structure force has become an urgent problem to be solved.

[0005] The above content is only used to assist in understanding the technical solution of this application, and does not represent an admission that the above content is prior art. Summary of the Invention

[0006] The main purpose of this application is to provide a method, device, equipment and storage medium for fatigue assessment of the force on an ocean truss cage structure, aiming to solve the technical problem of how to more efficiently and accurately solve the force on an ocean truss cage structure for fatigue assessment of the cage structure force.

[0007] To achieve the above object, the present application proposes a method for stress fatigue assessment of an ocean truss-type cage structure, and the method includes:

[0008] Obtain the cage structure load information and the assembled matrix set information;

[0009] Based on the cage structure load information and the assembled matrix set information, perform static-dynamic coupling analysis to determine the total displacement of the cage. The static-dynamic coupling analysis includes cage static analysis and cage dynamic analysis;

[0010] Calculate the stress of the cage structure according to the total displacement of the cage and the assembled matrix set information, and predict the fatigue life of the cage to complete the stress fatigue assessment of the cage structure.

[0011] In one embodiment, the step of obtaining the cage structure load information and the assembled matrix set information includes:

[0012] Obtain the user configuration file and the initialization matrix set;

[0013] Call the programming function to read the user configuration file to obtain the cage structure load information, and the cage structure load information includes node coordinate information, element connection information, material parameter information, load information, support information, and specified displacement information;

[0014] Initialize the initialization matrix set to adjust the initial value, and transform the coordinate system for matrix assembly to obtain the assembled matrix set information. The assembled matrix set information includes the global stiffness matrix, the global mass matrix, and the global damping matrix.

[0015] In one embodiment, the step of performing static-dynamic coupling analysis based on the cage structure load information and the assembled matrix set information to determine the total displacement of the cage includes:

[0016] Based on the cage structure load information and the assembled matrix set information, perform cage static analysis to locate the load position and determine the cage static displacement;

[0017] Based on the assembled matrix set information and the cage static displacement, perform cage dynamic analysis to update and iterate the displacement to determine the cage dynamic displacement;

[0018] Based on the cage static displacement and the cage dynamic displacement, determine the total displacement of the cage.

[0019] In one embodiment, the step of performing cage static analysis based on the cage structure load information and the assembled matrix set information to locate the load position and determine the cage static displacement includes:

[0020] Obtain the support type information, and the support type information includes rigid support, elastic support, and inclined support;

[0021] Modify the global stiffness matrix in the assembled matrix set information based on the support type information to determine the modified stiffness matrix;

[0022] Locate the specified displacements of the nodes based on the cage structure load information and the modified stiffness matrix, and quantify the row and column values of the load contribution adjustment matrix to determine the updated load vector and the updated stiffness matrix;

[0023] Obtain the static displacement of the cage based on the updated load vector and the updated stiffness matrix.

[0024] In one embodiment, the step of performing dynamic analysis of the cage to update and iterate the displacement based on the assembled matrix set information and the static displacement of the cage to determine the dynamic displacement of the cage includes:

[0025] Obtain the time step, the initial time step displacement, the initial time step velocity, the wave force, the wind force, and the current force;

[0026] Determine the dynamic load of the cage based on the wave force, the wind force, and the current force;

[0027] Obtain the initial acceleration based on the dynamic load of the cage, the initial time step velocity, the static displacement of the cage, and the assembled matrix set information;

[0028] Determine the predicted displacement and the predicted velocity of the cage based on the time step, the initial time step displacement, the initial time step velocity, and the initial acceleration;

[0029] Determine the acceleration at the time step based on the dynamic load of the cage, the predicted displacement of the cage, the predicted velocity of the cage, the time step, and the assembled matrix set information, calculate the displacement and velocity at the time step according to the acceleration at the time step, and update the predicted displacement and the predicted velocity of the cage to obtain the dynamic displacement of the cage.

[0030] In one embodiment, the step of calculating the force on the cage structure based on the total displacement of the cage and the assembled matrix set information and predicting the fatigue life of the cage to complete the fatigue assessment of the cage structure includes:

[0031] Determine the reaction force of the support based on the total displacement of the cage and the global stiffness matrix in the assembled matrix set information;

[0032] Extract the node displacement vector based on the total displacement of the cage, and transform the global stiffness matrix in the assembled matrix set information to determine the set of axial forces of the members;

[0033] Calculate the set of member stresses based on the set of axial forces of the members and the cross-sectional areas of the members;

[0034] Extract the key members based on the set of member stresses to perform the fatigue life assessment of the cage, and determine the fatigue life assessment result of the cage;

[0035] Predict the fatigue life of the cage based on the total displacement of the cage, the reaction force of the support, the axial force set of the members, the stress set of the members, and the evaluation result of the fatigue life of the cage, and complete the fatigue assessment of the mechanical stress of the cage structure.

[0036] In one embodiment, the steps of extracting key members based on the stress set of the members for the fatigue life assessment of the cage and determining the evaluation result of the fatigue life of the cage include:

[0037] Extract the deformation degree of the key members based on the stress set of the members, and extract the length of the key members to calculate the stress time history of the members;

[0038] Analyze the stress time history of the members to extract the stress amplitude, and determine the number of cycles and the fatigue life;

[0039] Calculate the cumulative damage based on the number of cycles and the fatigue life, and conduct the fatigue life assessment of the cage based on the cumulative damage to obtain the evaluation result of the fatigue life of the cage.

[0040] In addition, to achieve the above object, the present application also proposes a device for the fatigue assessment of the mechanical stress of an offshore truss cage structure, and the device for the fatigue assessment of the mechanical stress of the offshore truss cage structure includes:

[0041] An acquisition module, configured to acquire the cage structure load information and the assembled matrix set information;

[0042] A processing module, configured to perform static-dynamic coupling analysis based on the cage structure load information and the assembled matrix set information to determine the total displacement of the cage, and the static-dynamic coupling analysis includes the static analysis of the cage and the dynamic analysis of the cage;

[0043] An execution module, configured to calculate the mechanical stress of the cage structure according to the total displacement of the cage and the assembled matrix set information, and predict the fatigue life of the cage to complete the fatigue assessment of the mechanical stress of the cage structure.

[0044] In addition, to achieve the above object, the present application also proposes a device for the fatigue assessment of the mechanical stress of an offshore truss cage structure, and the device includes: a memory, a processor, and a computer program stored on the memory and executable on the processor, and the computer program is configured to implement the steps of the method for the fatigue assessment of the mechanical stress of the offshore truss cage structure as described above.

[0045] In addition, to achieve the above object, the present application also proposes a storage medium, the storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium, and when the computer program is executed by a processor, it implements the steps of the method for the fatigue assessment of the mechanical stress of the offshore truss cage structure as described above.

[0046] One or more technical solutions proposed in this application have at least the following technical effects:

[0047] A method for evaluating the stress fatigue of an ocean truss-type cage structure proposed in this embodiment obtains the load information of the cage structure and the information of the assembly matrix set; performs static-dynamic coupling analysis based on the load information of the cage structure and the information of the assembly matrix set to determine the total displacement of the cage, and the static-dynamic coupling analysis includes the static analysis of the cage and the dynamic analysis of the cage; calculates the stress of the cage structure according to the total displacement of the cage and the information of the assembly matrix set, and predicts the fatigue life of the cage to complete the stress fatigue evaluation of the cage structure. By obtaining the load information of the cage structure and the information of the assembly matrix set, combining the static analysis and dynamic analysis of the cage to calculate the total displacement of the cage, and calculating the stress of the cage structure, this application can predict the fatigue life of the cage, evaluate the performance of the cage, solve the stress state of the cage under complex working conditions more efficiently and accurately, identify fatigue-weak members in advance and optimize them, extend the service life of the cage, and significantly improve the reliability and safety of the ocean truss-type cage in the complex ocean environment. Description of the Drawings

[0048] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0049] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0050] Figure 1 It is a schematic flow chart provided for Embodiment 1 of the method for evaluating the stress fatigue of the ocean truss-type cage structure of this application;

[0051] Figure 2 It is the initialization flow chart of the method for evaluating the stress fatigue of the ocean truss-type cage structure of this application;

[0052] Figure 3 It is the static analysis flow chart of the method for evaluating the stress fatigue of the ocean truss-type cage structure of this application;

[0053] Figure 4 It is the dynamic analysis flow chart of the method for evaluating the stress fatigue of the ocean truss-type cage structure of this application;

[0054] Figure 5 It is the result output flow chart of the method for evaluating the stress fatigue of the ocean truss-type cage structure of this application;

[0055] Figure 6It is a schematic flow chart provided for the second embodiment of the method for evaluating the mechanical fatigue of the marine truss-type cage structure of the present application;

[0056] Figure 7 It is a schematic module structure diagram of the device for evaluating the mechanical fatigue of the marine truss-type cage structure according to the embodiment of the present application;

[0057] Figure 8 It is a schematic device structure diagram of the hardware operating environment involved in the method for evaluating the mechanical fatigue of the marine truss-type cage structure according to the embodiment of the present application.

[0058] The realization of the purpose, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners

[0059] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0060] In order to better understand the technical solutions of the present application, the following will be described in detail in conjunction with the accompanying drawings of the specification and specific implementation manners.

[0061] The main solution of the embodiment of the present application is: obtaining the load information of the cage structure and the information of the assembly matrix set; performing static-dynamic coupling analysis based on the load information of the cage structure and the information of the assembly matrix set to determine the total displacement of the cage, and the static-dynamic coupling analysis includes the static analysis of the cage and the dynamic analysis of the cage; calculating the mechanical force of the cage structure according to the total displacement of the cage and the information of the assembly matrix set, and predicting the fatigue life of the cage to complete the evaluation of the mechanical fatigue of the cage structure.

[0062] In this embodiment, for the convenience of description, the following will be described with the device for evaluating the mechanical fatigue of the marine truss-type cage structure as the execution subject.

[0063] Due to the fact that in the prior art, in the face of complex loads, complex boundary conditions and material properties such as wave forces, flow forces, wind forces and other dynamic loads of the cage, elastic supports, inclined supports, and the corrosion and fatigue effects of materials in the marine environment, it is difficult to accurately reflect the actual mechanical state and fatigue life of the cage structure, and the software in the existing practices is usually complex in function and high in learning cost, and it is difficult to carry out customized development for the special needs of the marine truss-type cage. Moreover, for the special analysis tools in the field of marine engineering, especially the tools that support elastic supports, inclined supports and dynamic loads of the cage, they are still relatively scarce, and it is impossible to accurately solve the mechanical force and fatigue life of the marine truss-type cage structure under actual working conditions.

[0064] The present application provides a solution, which obtains the load information of the cage structure and the information of the assembly matrix set; performs static-dynamic coupling analysis based on the load information of the cage structure and the information of the assembly matrix set to determine the total displacement of the cage, and the static-dynamic coupling analysis includes the static analysis of the cage and the dynamic analysis of the cage; calculates the force on the cage structure according to the total displacement of the cage and the information of the assembly matrix set, and predicts the fatigue life of the cage to complete the fatigue assessment of the cage structure force.

[0065] As can be seen from the above embodiments, the present application obtains the load information of the cage structure and the information of the assembly matrix set, calculates the total displacement of the cage by combining the static analysis and the dynamic analysis of the cage, and calculates the force on the cage structure, so as to predict the fatigue life of the cage, evaluate the performance of the cage, solve the force state of the cage under complex working conditions more efficiently and accurately, identify the fatigue-weak members in advance and optimize them, extend the service life of the cage, and significantly improve the reliability and safety of the offshore truss cage in the complex marine environment.

[0066] Based on this, an embodiment of the present application provides a method for fatigue assessment of the force on an offshore truss cage structure, referring to Figure 1 , Figure 1 is a schematic flowchart of the first embodiment of the method for fatigue assessment of the force on the offshore truss cage structure of the present application.

[0067] In this embodiment, the method for fatigue assessment of the force on the offshore truss cage structure includes steps S10 to S30:

[0068] Step S10, obtaining the load information of the cage structure and the information of the assembly matrix set;

[0069] It should be noted that the load information of the cage structure reflects the characteristics of the actual external load parameters that the cage receives in the actual marine environment, and the information of the assembly matrix set reflects the characteristics of the matrix set that describes the mechanical and geometric characteristics of the cage structure when assembled.

[0070] It can be understood that the intersection points and constraint points of the members are nodes, and each member is a unit. When the user numbers the nodes and units of the truss structure to be solved, they need to be arranged in order without omission or repetition. In this way, the last node number of the structure is the total number of nodes, and the last unit number is the total number of units. The numbering of nodes and units is carried out separately.

[0071] In addition, it should be noted that the nodes in the truss structure are hinge joints, and the units intersecting at the nodes can rotate freely around the nodes. Such nodes can be idealized as a point geometrically. A point can have three independent movement modes in space, that is, there are three independent coordinates x, y, z that can be changed in the rectangular coordinate system, which are called three degrees of freedom. Therefore, in a space truss, a node has three degrees of freedom.

[0072] For the convenience of understanding, the acquisition of the load information of the cage structure and the information of the assembled matrix set is taken as an example for illustration. Among them, the information acquisition device is the information acquisition module, and the storage device is the memory.

[0073] The information acquisition module obtains the user configuration file and the initialization matrix set, that is, as Figure 2 shown, Figure 2 This is the initialization flowchart of the stress fatigue assessment method for the ocean truss cage structure of this application. It obtains the user-defined input file. If the user-defined input file is input_data.txt, it obtains the global stiffness matrix K, the mass matrix M, and the damping matrix C. It calls the programming function to read the user configuration file to obtain the load information of the cage structure. The load information of the cage structure includes node coordinate information, element connection information, material parameter information, load information, support information, and specified displacement information. That is, it calls the MATLAB function to read the input data from the user-defined input file, including node coordinates, element connections, material parameters (such as elastic modulus E), load information, support information, and specified displacements. Initialize the initialization matrix set to adjust the initial values, and transform the coordinate system for matrix assembly to obtain the information of the assembled matrix set. The information of the assembled matrix set includes the global stiffness matrix, the global mass matrix, and the global damping matrix. That is, initialize the global stiffness matrix K, the mass matrix M, and the damping matrix C, set the initial values of all matrices and vectors to 0, and then perform assembly respectively to obtain the information of the assembled matrix set.

[0074] Among them, calculating the element stiffness matrix K in the element coordinate system is required for assembling the global stiffness matrix e , where the stiffness equation of element e can be expressed as:

[0075] F e =K e U e

[0076] And define the coordinate transformation matrix T to transform the element stiffness matrix K in the element coordinate system e to the global coordinate system. The global stiffness equation can be expressed as:

[0077] KU = F

[0078] The element stiffness matrix in the global coordinate system is T T K e T. Thus, according to the node degree of freedom numbering method, the transformed element stiffness matrix T T K e T is added to the corresponding position of the global stiffness matrix K to obtain the assembled global stiffness matrix. The node degree of freedom numbering method can express the local or global degree of freedom number calculation formula as:

[0079] a = b(k - 1) + c

[0080] Among them, k represents the local or overall node number, a represents the local or overall degree of freedom number, and b and c respectively represent the number of node degrees of freedom and the node degree of freedom number.

[0081] And assembling the global mass matrix M requires calculating the mass of the bar element, which is expressed as:

[0082] m = ρAL

[0083] Where ρ is the material density of the bar element, A is the cross-sectional area of the bar element, and L is the length of the bar element.

[0084] And evenly distribute the mass of the bar element to the two end nodes of the element, and then add it to the corresponding position of the global mass matrix M according to the node degree of freedom numbering to obtain the assembled global mass matrix.

[0085] And assembling the global damping matrix can be expressed as:

[0086] C = αM + βK.

[0087] Where the damping coefficients α or β can be determined according to the damping characteristics of the actual structure to obtain the assembled global damping matrix.

[0088] In a feasible implementation manner, step S10 may include steps A11 to A13:

[0089] Step A11, obtain the user configuration file and the initialization matrix set;

[0090] It should be noted that the user configuration file reflects the characteristics of the personalized parameters set by the user for a specific ocean truss cage structure analysis task, and the initialization matrix set reflects the characteristics of a matrix set with the same row and column sizes and initial values of zero.

[0091] It can be understood that the user configuration file is the initial data file provided by the user when performing the force analysis of the ocean truss cage structure, which may include the geometric information, material properties, load conditions, and boundary conditions of the cage structure, and the initialization matrix set is the initial global stiffness matrix, global mass matrix, and global damping matrix generated according to the information in the user configuration file before performing the structural analysis.

[0092] Step A12, call the programming function to read the user configuration file to obtain the load information of the cage structure, and the load information of the cage structure includes node coordinate information, element connection information, material parameter information, load information, support information, and specified displacement information;

[0093] It should be noted that the node coordinate information reflects the characteristics of the specific positions of the nodes in the cage structure in space, the unit connection information reflects the characteristics of the connection relationships between the nodes in the cage structure, the material parameter information reflects the characteristics of the material parameters used in the cage structure, the load information reflects the characteristics of various external forces borne by the cage structure during actual use, the support information reflects the characteristics of the boundary conditions of the cage structure, and the specified displacement information reflects the characteristics of the displacement constraints or preset displacements of the nodes in specific directions.

[0094] It can be understood that the load information of the cage structure can be all the external forces related to the offshore truss cage structure, characterizing the nature and magnitude of the forces borne by the cage during actual use.

[0095] In addition, it should be noted that based on the load information of the cage structure, the actual working conditions of the offshore truss cage structure can be comprehensively and accurately described, so that the design of the cage structure can be optimized, its anti-wave and anti-wind ability and service life can be improved, the maintenance of the cage can be more convenient, the operation cost can be reduced, and the overall performance and economic benefits of the offshore aquaculture facilities can be significantly enhanced.

[0096] Step A13, initialize the initial values of the initialization matrix set and transform the coordinate system for matrix assembly to obtain the assembled matrix set information, where the assembled matrix set information includes the global stiffness matrix, the global mass matrix, and the global damping matrix.

[0097] It should be noted that the global stiffness matrix reflects the characteristics of the deformation ability of the cage structure under external loads, the global mass matrix reflects the characteristics of the mass distribution state of the cage structure, and the global damping matrix reflects the characteristics of the energy dissipation ability of the cage structure during movement.

[0098] It can be understood that through the transformation of the matrix form, the assembled matrix set information can be used to efficiently solve the force state and deformation of the cage structure by matrix operations. Among them, the global stiffness matrix is assembled by the stiffness matrices of each unit according to the node degrees of freedom, which determines the deformation degree and internal force distribution of the structure under loads; the global mass matrix is assembled by the masses of each unit according to the node degrees of freedom and is used to calculate the inertial force in dynamic analysis; the global damping matrix is assembled by the unit damping matrices and is used to describe the damping characteristics of the cage structure under the dynamic loads of the cage, that is, the damping matrix can be expressed as a linear combination of the mass matrix and the stiffness matrix and is determined according to the damping characteristics of the actual structure.

[0099] In addition, it should be noted that in order to facilitate the matrix analysis of the bar structure, two coordinate systems can be adopted, namely the global coordinate system and the element coordinate system. The coordinate system established for the entire discrete structure is the global coordinate system, and the physical quantities of all nodes and elements on the structure can be measured by this coordinate system. When examining a single discrete element alone, the coordinate system specially established for this element is the element coordinate system, and the physical quantities of this element and its two end nodes can be measured by the element coordinate system.

[0100] Step S20: Perform static-dynamic coupling analysis based on the cage structure load information and the assembled matrix set information to determine the total displacement of the cage. The static-dynamic coupling analysis includes static analysis of the cage and dynamic analysis of the cage.

[0101] It should be noted that the total displacement of the cage reflects the characteristics of the final deformation state of the cage structure under the combined action of static and dynamic loads.

[0102] It can be understood that the total displacement of the cage can characterize the displacement of the cage under static loads and the displacement change under the dynamic loads of the cage, and is used to evaluate the overall mechanical performance and deformation of the cage structure.

[0103] In addition, it should be noted that the static analysis of the cage is to analyze the stress and deformation of the cage structure under static loads without considering time factors, and the dynamic analysis of the cage is to analyze the stress and deformation of the cage structure under the dynamic loads of the cage considering time factors.

[0104] For easy understanding, taking the determination of the total displacement of the cage as an example for illustration, where the information acquisition device is the information acquisition module, the storage device is the memory, and the processing device is the processing module.

[0105] The information acquisition module obtains the cage structure load information and the assembled matrix set information, and obtains the support type information. The support type information includes rigid supports, elastic supports, and inclined supports. Based on the support type information, the global stiffness matrix in the assembled matrix set information is corrected to determine the corrected stiffness matrix, that is, as Figure 3 shown, Figure 3 This is the static analysis flowchart of the method for evaluating the mechanical fatigue of the offshore truss cage structure in this application. After assembling the global stiffness matrix, the global mass matrix, and the global damping matrix to obtain the assembled matrix set information, the global stiffness matrix is modified according to the support type to obtain the corrected stiffness matrix. If it is a rigid support, the row elimination correction method is used to process the global stiffness matrix, and the values other than the main diagonal elements in the rows and columns related to its corresponding nodes in the global stiffness matrix are set to 0, and then the load vector F _staticThe corresponding load value is 0. For an elastic support, the diagonal element superposition method is used to add the stiffness value of the elastic support at the position of the corresponding degree of freedom on the main diagonal of the global stiffness matrix. For an inclined support, the support direction vector is unitized, and the stiffness matrix of the inclined support in the element coordinate system is calculated according to the unitized support direction vector n and the stiffness value k of the inclined support, which is expressed as:

[0106] K support =kn T n

[0107] 0Convert the stiffness matrix of the inclined support in the element coordinate system to the global coordinate system, and then add the converted stiffness matrix T T K support T to the corresponding position in the global stiffness matrix.

[0108] Based on the load information of the net cage structure and the modified stiffness matrix, locate the specified displacements of the nodes, and quantify the row and column values of the load contribution adjustment matrix to determine the updated load vector and the updated stiffness matrix, that is, the specified displacements are processed by the row elimination correction method, and the updated load vector F_static and the global stiffness matrix K are updated.

[0109] For each node with a specified displacement, calculate its contribution to the load vector, so as to update the load vector, which is expressed as:

[0110] F _static =F _static -K·U node

[0111] where U node is the specified displacement of this node.

[0112] Updating the global stiffness matrix is to set the rows and columns related to this node in the global stiffness matrix to 0, and then set the diagonal element corresponding to this node to 1 to ensure that the displacement value of this node is the specified value, and directly assign the specified displacement value to the corresponding position of the load vector F _static of.

[0113] Based on the updated load vector and the updated stiffness matrix, the static displacement of the net cage is obtained, that is, the static displacement U_static is solved, which is expressed as:

[0114] U_static=K -1 F_static

[0115] Obtain the time step, the displacement at the initial time step, the velocity at the initial time step, the wave force, the wind force and the current force, and determine the dynamic load of the net cage based on the wave force, the wind force and the current force, that is, as Figure 4 shown Figure 4This is the dynamic analysis flowchart of the stress fatigue assessment method for the ocean truss-type cage structure in this application. Initialize the time vector and initial conditions for dynamic analysis. The displacement U0 at the initial time step is the static displacement U_static, the velocity V0 at the initial time step is 0, the wave force is F_wave, the wind force is F_wind, and the current force is F_current. Calculate the dynamic load of the cage at the current time step, expressed as:

[0116] F_dynamic = F_wave + F_wind + F_current

[0117] Among them, the wave force is calculated by the Morison equation using the Airy linear wave theory, the wind force is calculated using the square relationship with the Davenport wind speed spectrum, and the current force is calculated by the drag force formula with a constant flow velocity.

[0118] Based on the cage dynamic load, the initial time step velocity, the cage static displacement, and the information of the assembled matrix set, obtain the initial acceleration. That is, directly use the displacement U0 at the initial time step and the velocity V0 at the initial time step to calculate the initial acceleration, expressed as:

[0119] A = M -1 (F _dynamic - CV0 - KU0).

[0120] Based on the time step, the initial time step displacement, the initial time step velocity, and the initial acceleration, determine the predicted displacement and predicted velocity of the cage. That is, calculate the predicted displacement U pred , expressed as:

[0121] U pred = U t-1 + Δt·V t-1 +(0.5 - β)·Δt 2 ·A t-1

[0122] Among them, U t-1 represents the displacement at the previous time step, V t-1 represents the velocity at the previous time step, and Δt represents the time step.

[0123] Calculate the predicted velocity V pred , expressed as:

[0124] V pred = V t-1 +(1 - γ)·Δt·A t-1

[0125] Among them, A t-1 represents the acceleration at the previous time step.

[0126] At this time, the initial predicted displacement and predicted velocity of the cage are calculated.

[0127] After that, the acceleration at the time step can be determined based on the dynamic load of the cage, the predicted displacement of the cage, the predicted velocity of the cage, the time step, and the information of the assembled matrix set. The displacement and velocity at the time step are calculated according to the acceleration at the time step, and the predicted displacement and predicted velocity of the cage are updated to obtain the dynamic displacement U_dynamic of the cage.

[0128] The predicted displacement and predicted velocity of the cage can always be calculated by the above formula. However, the velocity, displacement, and acceleration at each time step are different. Therefore, the velocity, displacement, and acceleration at the time step can be updated by referring to the following method, and then calculated again to update the predicted displacement and predicted velocity of the cage and record them.

[0129] That is, solve the acceleration at the time step, expressed as:

[0130] A t =(M + γ·Δt·C + β·Δt 2 ·K) -1 ·(F _dynamic - C·V pred - K·U pred )

[0131] where β and γ are parameters of the Newmark-beta method, and usually β = 0.25 and γ = 0.5 are taken to ensure numerical stability. Calculate the displacement and velocity at the time step, expressed as:

[0132] U t = U pred + β·Δt 2 ·A t , V t = V pred + γ·Δt·A t

[0133] Store the displacement U t at each time step into the U_dynamic matrix.

[0134] Determine the total displacement of the cage based on the static displacement and the dynamic displacement of the cage, that is, add the static displacement and the dynamic displacement to obtain the total displacement U_total of the cage, expressed as:

[0135] U_total = U_static + U_dynamic

[0136] Step S30, calculate the force on the cage structure according to the total displacement of the cage and the information of the assembled matrix set, and predict the fatigue life of the cage to complete the fatigue assessment of the cage structure force.

[0137] It should be noted that the force on the cage structure reflects the force characteristics of the cage under various external loads and internal constraint conditions.

[0138] It can be understood that by calculating the force on the cage structure, the mechanical properties of the cage under actual working conditions can be comprehensively and accurately evaluated, which can be used for fatigue life assessment and safety analysis of the cage, identify the weak links of the cage structure, and take reinforcement or optimization measures in advance, so as to extend the service life of the cage, reduce maintenance costs, and improve the reliability and safety of the cage in complex marine environments.

[0139] For the convenience of understanding, taking the calculation of the force on the cage structure as an example, the information acquisition device is the information acquisition module, the storage device is the memory, and the execution device is the execution module.

[0140] The information acquisition module obtains the total displacement U_total of the cage and the information K of the assembled matrix set, and determines the support reaction force according to the total displacement of the cage and the global stiffness matrix in the information of the assembled matrix set, that is, as Figure 5 shown, Figure 5 This is the result output flow chart of the method for fatigue assessment of the force on the marine truss cage structure of the present application. According to the node displacement result, the support reaction force is calculated through matrix operation and mechanical formula, which is expressed as:

[0141] R = K * U_total

[0142] Based on the total displacement of the cage, the node displacement vector is extracted, and the global stiffness matrix in the information of the assembled matrix set is transformed to determine the axial force set of the members, that is, the displacement vectors u of the two end nodes of the member unit are extracted from the node displacement vector U_total [[ID=2,2]] e and then the corresponding axial force N of the member is calculated, which is expressed as:

[0143] N = T T K e u e

[0144] Based on the axial force set of the members and the cross-sectional area of the members, the stress set of the members is calculated, that is, after obtaining the axial force, the corresponding stress σ of the member is further calculated, which is expressed as:

[0145]

[0146] where A1 represents the cross-sectional area of the member.

[0147] Based on the stress set of the members, the deformation degree of the key members is extracted, and the length of the key members is extracted to calculate the stress time history of the members, that is, in the dynamic analysis part, the node displacement U_dynamic at each time step is calculated, and the stress time history of each member is calculated according to the node displacement, which is expressed as:

[0148]

[0149] Among them, δ(t) is the axial deformation of the rod member.

[0150] Analyze the stress time history of the rod member to extract the stress amplitude, determine the number of cycles and fatigue life, that is, extract the stress time history of the key rod members, such as the parts with the largest force or stress concentration. Use the Rainflow Counting method to analyze the stress time history, extract the stress amplitude Δσ and the number of cycles n, count the number of cycles corresponding to different stress amplitudes, and obtain the S-N curve data of the material. Look up the fatigue life N corresponding to each stress amplitude Δσ through the S-N curve. Among them, the S-N curve data of the material can be obtained from preset experiments.

[0151] Calculate the cumulative damage based on the number of cycles and the fatigue life, and evaluate the fatigue life of the fish cage based on the cumulative damage to obtain the fish cage fatigue life evaluation result, that is, calculate the damage D corresponding to each stress amplitude i , expressed as:

[0152]

[0153] Among them, n i is the number of cycles of the stress amplitude Δσ i , N i is the fatigue life of the stress amplitude Δσ i .

[0154] Then calculate the total cumulative damage D total , expressed as:

[0155] D total = ∑D i

[0156] If D total ≥1, the fish cage fatigue life evaluation result indicates that the structure has reached the fatigue life. If D total 5]<1, the fish cage fatigue life evaluation result indicates that the structure still has a certain fatigue life.

[0157] Predict the fish cage fatigue life based on the total displacement of the fish cage, the support reaction force, the axial force set of the rod members, the stress set of the rod members, and the fish cage fatigue life evaluation result to complete the fatigue assessment of the fish cage structure's force, that is, call the MATLAB function to write the node displacement, support reaction force, internal force and stress of the rod members, and the fish cage fatigue life evaluation result into the result output file specified by the user, such as output_data.txt, for the user to view.

[0158] In a feasible implementation, step S30 may include steps B11 to B16:

[0159] Step B11, obtaining the cross-sectional area of the rod;

[0160] It should be noted that the cross-sectional area of the rod reflects the characteristics of the cross-sectional area of the rod perpendicular to its axis direction.

[0161] It can be understood that the cross-sectional area of the rod can be used to describe the size of the rod in the direction perpendicular to the axis. The axis of the rod is a straight line passing through the center in the length direction of the rod. The geometric shape of the rod is symmetric along the axis, and the cross-section is a section perpendicular to the axis of the rod. For example, for a straight rod, the cross-section is a plane perpendicular to the length direction of the rod, and the cross-sectional area is the area size of the cross-section, which can be obtained by measuring the dimensions of the cross-section or by calculation.

[0162] Step B12, determining the support reaction force according to the total displacement of the net cage and the global stiffness matrix in the assembled matrix set information;

[0163] It should be noted that the support reaction force reflects the characteristics of the reaction force generated by the support on the structure when the net cage structure is subjected to external loads.

[0164] It can be understood that the support reaction force can characterize the constraint effect of the support on the net cage structure and the stress state of the structure at the support. By calculating the support reaction force, the stress condition of the net cage structure at the support under actual working conditions can be clarified, the mechanical properties of the net cage structure under actual working conditions can be comprehensively and accurately evaluated, the weak links of the net cage structure can be identified, and reinforcement or optimization measures can be taken in advance.

[0165] Step B13, extracting the node displacement vector based on the total displacement of the net cage, and transforming the global stiffness matrix in the assembled matrix set information to determine the axial force set of the rods;

[0166] It should be noted that the axial force set of the rods reflects the characteristics of the set of axial forces borne by all the rods in the net cage structure under the stress state.

[0167] It can be understood that the axial force set of the rods can characterize the stress state of each rod in the net cage structure under actual loads, so as to facilitate the maintenance of the rods, effectively extend the service life of the net cage, reduce the maintenance cost, and improve the reliability and safety of the net cage in complex marine environments.

[0168] Step B14, calculating the stress set of the rods based on the axial force set of the rods and the cross-sectional area of the rods;

[0169] It should be noted that the stress set of the rods reflects the characteristics of the set of stresses borne by all the rods in the net cage structure under the stress state.

[0170] It can be understood that the stress set of the rods can characterize the stress distribution of each rod in the cage structure under actual loads, measure whether the rod materials will deform, fatigue or be damaged, so as to facilitate the maintenance of the rods and effectively extend the service life of the cage.

[0171] Step B15: Based on the stress set of the rods, extract key rods for fatigue life assessment of the cage, and determine the fatigue life assessment result of the cage;

[0172] It should be noted that the fatigue life assessment result of the cage reflects the characteristics of the assessment result of the cage life obtained by assessing the fatigue life of the cage structure under actual working conditions.

[0173] It can be understood that the fatigue life assessment result of the cage can evaluate the continuous use state of the cage structure, clarify the fatigue cumulative damage degree of each key rod in the cage structure under actual working conditions, and whether the overall structure reaches the fatigue life limit, so as to timely maintain the cage or replace the cage, significantly improving the reliability and safety of the cage in the complex marine environment.

[0174] In a feasible implementation, step B14 may include steps C11 to C13:

[0175] Step C11: Based on the stress set of the rods, extract the deformation degree of the key rods, and extract the key rod lengths to calculate the stress time history of the rods;

[0176] It should be noted that the stress time history of the rods reflects the characteristics of the stress change of the rods in the cage structure under the dynamic load of the cage over time.

[0177] It can be understood that the stress time history of the rods can clarify the stress state of the rods at different time points. Especially for the rods with large stress or stress concentration, the stress time history can reveal the fatigue characteristics of the rods under the dynamic load of the cage, so as to identify the stress concentration parts and key rods with large stress to evaluate the actual life of the cage.

[0178] Step C12: Analyze the stress time history of the rods to extract the stress amplitude, and determine the number of cycles and fatigue life;

[0179] It should be noted that the number of cycles reflects the characteristics of the number of times the stress cycles within a certain specific stress amplitude range in the stress time history of the rods, and the fatigue life reflects the characteristics of the limit that the material can withstand without fatigue failure under a given stress amplitude.

[0180] It can be understood that the number of cycles can characterize the repetition frequency and cumulative degree of stress changes of the rod under the dynamic load of the net cage. A higher number of cycles means that the rod has experienced more repeated loadings at this stress level, resulting in more serious fatigue accumulation and causing fatigue loss of the material. The fatigue life characterizes the durability of the material under the dynamic load of the net cage and can be determined using the S-N curve of the material. Each point on the curve corresponds to a stress amplitude and the corresponding fatigue life.

[0181] Step C13: Calculate the cumulative damage based on the number of cycles and the fatigue life, and conduct a fatigue life assessment of the net cage based on the cumulative damage to obtain the fatigue life assessment result of the net cage.

[0182] It should be noted that the cumulative damage reflects the characteristics of the cumulative fatigue damage degree of the key rods in the net cage structure under the action of various stress amplitudes and the corresponding number of cycles.

[0183] It can be understood that the cumulative damage can characterize the fatigue cumulative effect of the rod under actual working conditions due to repeated loadings. The higher the cumulative damage value, the more serious the fatigue cumulative effect of the rod, and the closer the fatigue life of the structure is to the limit.

[0184] Step B16: Predict the fatigue life of the net cage based on the total displacement of the net cage, the support reaction force, the set of axial forces of the rods, the set of rod stresses, and the fatigue life assessment result of the net cage to complete the fatigue assessment of the mechanical stress of the net cage structure.

[0185] It can be understood that by predicting the fatigue life of the net cage structure, fatigue weak links can be identified in advance, the net cage structure can be optimized specifically, the service life of the net cage can be extended, the maintenance cost can be reduced, and the reliability and safety of the net cage in a complex marine environment can be significantly improved.

[0186] A method for evaluating the mechanical fatigue of an ocean truss-type cage structure proposed in this embodiment obtains the load information and the assembly matrix set information of the cage structure; performs static-dynamic coupling analysis based on the load information of the cage structure and the assembly matrix set information to determine the total displacement of the cage, and the static-dynamic coupling analysis includes static analysis of the cage and dynamic analysis of the cage; calculates the mechanical stress of the cage structure according to the total displacement of the cage and the assembly matrix set information, and predicts the fatigue life of the cage to complete the evaluation of the mechanical fatigue of the cage structure. It solves the technical problem of how to more efficiently and accurately solve the mechanical stress of the ocean truss-type cage structure for the evaluation of the mechanical fatigue of the cage structure. Compared with the prior art, this application obtains the load information and the assembly matrix set information of the cage structure, and performs static analysis and dynamic analysis to calculate the total displacement of the cage, thereby calculating the mechanical stress of the cage structure and predicting the fatigue life of the cage, evaluating the mechanical fatigue of the cage, realizing the accurate analysis of the cage structure under complex working conditions, solving the nodal displacement, support reaction and internal force of the truss-type cage structure under various support types and specified displacement conditions, and the calculation results can be used as a reference for the optimization design of the cage structure, reducing material costs and construction difficulties, extending the service life, and significantly improving the reliability and safety of the cage in the complex marine environment.

[0187] Based on the first embodiment of the present application, in the second embodiment of the present application, the same or similar content as in the above-mentioned embodiment 1 can be referred to the above introduction and will not be repeated hereinafter.

[0188] In this embodiment, refer to Figure 6 , Figure 6 FIG. is a schematic flow chart provided for the second embodiment of the method for evaluating the mechanical fatigue of the ocean truss-type cage structure of the present application. Step S20 specifically includes steps S21 to S23:

[0189] Step S21, perform static analysis of the cage based on the load information of the cage structure and the assembly matrix set information to locate the load position and determine the static displacement of the cage;

[0190] It should be noted that the static displacement of the cage reflects the characteristics of the deformation degree of the cage structure under the action of static loads.

[0191] For easy understanding, taking the determination of the static displacement of the cage as an example for illustration, where the information acquisition device is the information acquisition module, the storage device is the memory, and the processing device is the processing module.

[0192] The information acquisition module obtains the information of the cage structure load and the assembly matrix set, and obtains the bearing type information, where the bearing type information includes rigid bearings, elastic bearings, and inclined bearings. Based on the bearing type information, the global stiffness matrix in the assembly matrix set information is corrected to determine the corrected stiffness matrix, that is, the global stiffness matrix is modified according to the bearing type to obtain the corrected stiffness matrix. If it is a rigid bearing, the row elimination correction method is used to process the global stiffness matrix, and the values other than the main diagonal elements in the rows and columns related to its corresponding nodes in the global stiffness matrix are set to 0, and then the load vector F _static in the corresponding load value is set to 0. If it is an elastic bearing, the diagonal element superposition method is used, and the stiffness value of the elastic bearing is added to the position corresponding to the degree of freedom on the main diagonal of the global stiffness matrix. If it is an inclined bearing, the bearing direction vector is unitized, and the stiffness matrix of the inclined bearing in the element coordinate system is calculated according to the unitized bearing direction vector n and the stiffness value k of the inclined bearing, which is expressed as:

[0193] K support =kn T n

[0194] The stiffness matrix of the inclined bearing in the element coordinate system is transformed to the global coordinate system, and then the transformed stiffness matrix T T K support T of the inclined bearing is added to the corresponding position in the global stiffness matrix.

[0195] Based on the cage structure load information and the corrected stiffness matrix, the specified displacements of the nodes are located, and the row and column values of the load contribution adjustment matrix are quantified to determine the updated load vector and the updated stiffness matrix, that is, the row elimination correction method is used to process the specified displacements, and the load vector F_static and the global stiffness matrix K are updated.

[0196] For each specified displacement node, calculate its contribution to the load vector, so as to update the load vector, which is expressed as:

[0197] F _static =F _static -K·U node

[0198] where U node is the specified displacement of this node.

[0199] Updating the global stiffness matrix is to set the rows and columns related to this node in the global stiffness matrix to 0, and then set the diagonal element corresponding to this node to 1 to ensure that the displacement value of this node is the specified value, and directly assign the specified displacement value to the corresponding position of the load vector F _static .

[0200] Based on the updated load vector and the updated stiffness matrix, the static displacement of the cage is obtained, that is, the static displacement U_static is solved, which is expressed as:

[0201] U_static = K -1 F_static

[0202] Perform subsequent processing based on the static displacement.

[0203] In a feasible implementation, step S21 may include steps D11 to D14:

[0204] Step D11, obtain the support type information, where the support type information includes rigid supports, elastic supports, and inclined supports;

[0205] It should be noted that the support type information reflects the characteristics of the specific type of support in the cage structure.

[0206] It can be understood that the support type information can characterize the boundary conditions and constraint characteristics of the cage structure under actual working conditions. Different support types will result in significant differences in the force and deformation behaviors of the cage structure under load, effectively avoiding analysis errors caused by improper handling of boundary conditions and ensuring the reliability and safety of the cage structure in complex marine environments.

[0207] Step D12, based on the support type information, correct the global stiffness matrix in the assembled matrix set information to determine the corrected stiffness matrix;

[0208] [[ID=z5]]It should be noted that the corrected stiffness matrix reflects the characteristics of the matrix after adjusting the global stiffness matrix of the cage structure considering the support type information.

[0209] It can be understood that the corrected stiffness matrix can characterize the overall stiffness characteristics of the cage structure under actual working conditions considering the support constraint conditions, thus more accurately describing the deformation and force behaviors of the cage structure under load.

[0210] Step D13, based on the cage structure load information and the corrected stiffness matrix, locate the specified displacements of the nodes, and quantify the row and column values of the load contribution adjustment matrix to determine the updated load vector and the updated stiffness matrix;

[0211] It should be noted that the updated load vector reflects the characteristics of the load distribution actually acting on the structure of the cage structure considering the support type and the specified displacements, and the updated stiffness matrix reflects the characteristics of the change in the overall stiffness characteristics of the cage structure considering the support constraints and the specified displacements.

[0212] It can be understood that the updated load vector can characterize the influence of the support on load transfer and the adjustment of the specified displacement on the load distribution, so as to more accurately describe the stress state of the cage structure under actual working conditions, while the updated stiffness matrix can more accurately describe the mechanical behavior of the structure by adjusting the row and column values of the global stiffness matrix.

[0213] Step D14, obtain the static displacement of the cage based on the updated load vector and the updated stiffness matrix.

[0214] It can be understood that the static displacement of the cage can comprehensively evaluate the deformation and stress state of the cage structure under static loads, identify possible areas with excessive deformation or stress concentration, so as to optimize the design of the cage structure, improve its anti-deformation ability and stability, and by identifying static deformation problems in advance, corresponding reinforcement measures can be taken to reduce maintenance costs, extend the service life of the cage, and improve the reliability and safety of the cage in complex marine environments.

[0215] Step S22, perform iterative update of the dynamic analysis of the cage based on the information of the assembly matrix set and the static displacement of the cage to determine the dynamic displacement of the cage;

[0216] It should be noted that the dynamic displacement of the cage reflects the characteristics of the displacement change of the cage structure under dynamic loads of the cage.

[0217] For the convenience of understanding, taking the determination of the dynamic displacement of the cage as an example, the information acquisition device is the information acquisition module, the storage device is the memory, and the processing device is the processing module.

[0218] The information acquisition module obtains the time step, the displacement at the initial time step, the velocity at the initial time step, the wave force, the wind force, and the current force, and determines the dynamic load of the cage based on the wave force, the wind force, and the current force, that is, initializes the time vector and the initial conditions of the dynamic analysis. The displacement U0 at the initial time step is the static displacement U_static, the velocity V0 at the initial time step is 0, the wave force is F_wave, the wind force is F_wind, and the current force is F_current. Calculate the dynamic load of the cage at the current time step, expressed as:

[0219] F_dynamic = F_wave + F_wind + F_current

[0220] Among them, the wave force is calculated by the Morison equation using the Airy linear wave theory, the wind force is calculated using the square relationship with the Davenport wind speed spectrum, and the current force is calculated by the drag force formula with a constant flow velocity.

[0221] The initial acceleration is obtained based on the cage dynamic load, the initial time step velocity, the cage static displacement, and the assembled matrix set information. That is, directly using the initial time step displacement U0 and the initial time step velocity V0, the initial acceleration is calculated and expressed as:

[0222] A = M -1 (F _dynamic - CV0 - KU0).

[0223] The cage predicted displacement and the cage predicted velocity are determined based on the time step, the initial time step displacement, the initial time step velocity, and the initial acceleration. That is, the predicted displacement U pred is calculated and expressed as:

[0224] U pred = U t-1 + Δt·V t-1 +(0.5 - β)·Δt 2 ·A t-1

[0225] where U t-1 represents the displacement at the previous time step, V t-1 represents the velocity at the previous time step, and Δt represents the time step.

[0226] The predicted velocity V pred is calculated and expressed as:

[0227] V pred = V t-1 +(1 - γ)·Δt·A t-1

[0228] where A t-1 represents the acceleration at the previous time step.

[0229] At this time, the initial cage predicted displacement and the cage predicted velocity are calculated.

[0230] After that, the time step acceleration can be determined based on the cage dynamic load, the cage predicted displacement, the cage predicted velocity, the time step, and the assembled matrix set information. The time step displacement and the time step velocity are calculated according to the time step acceleration, and the cage predicted displacement and the cage predicted velocity are updated to obtain the cage dynamic displacement U_dynamic.

[0231] The cage predicted displacement and the cage predicted velocity can always be calculated by the above formulas. However, the velocity, displacement, and acceleration at each time step are different. Therefore, the time step velocity, the time step displacement, and the time step acceleration can be updated by referring to the following method, and then recalculated to update the cage predicted displacement and the cage predicted velocity and record them.

[0232] That is, to solve the acceleration at the time step, which is expressed as:

[0233] A t =(M + γ·Δt·C + β·Δt 2 ·K) -1 ·(F _dynamic -C·V pred -K·U pred )

[0234] where β and γ are parameters of the Newmark-beta method. Usually, β = 0.25 and γ = 0.5 are taken to ensure numerical stability. Calculate the displacement and velocity at the time step, which are expressed as:

[0235] U t = U pred + β·Δt 2 ·A t , V t = V pred + γ·Δt·A t

[0236] Store the displacement U t at each time step into the U_dynamic matrix to obtain the dynamic displacement of the net cage.

[0237] In a feasible implementation manner, step S22 may include steps E11 to E15:

[0238] Step E11, obtain the time step, the initial displacement at the time step, the initial velocity at the time step, the wave force, the wind force, and the current force;

[0239] It should be noted that the initial velocity at the time step reflects the characteristics of the motion state of the net cage structure at the initial moment of dynamic analysis, the time step reflects the characteristics of the time period divided in dynamic analysis, the initial displacement at the time step reflects the characteristics of the displacement change of the net cage structure within the initial time step, the initial velocity at the time step reflects the characteristics of the velocity change of the net cage structure within the initial time step, the wave force reflects the characteristics of the force exerted by the wave on the net cage structure, the wind force reflects the characteristics of the force exerted by the wind on the net cage structure, and the current force reflects the characteristics of the force exerted by the water flow on the net cage structure.

[0240] It is understandable that the initial time-step velocity can characterize the initial motion trend of the cage structure at the start of the action of the cage dynamic load. The time step can characterize the degree of time discretization in the dynamic analysis, that is, the size of each time step. A smaller time step can improve the analysis accuracy but increase the computational amount. The initial time-step displacement can characterize the deformation of the cage structure under the action of the cage dynamic load at the initial time step. The initial time-step velocity can characterize the motion velocity of the cage structure under the action of the cage dynamic load at the initial time step. The wave force, the wind force, and the flow force all characterize the actual cage dynamic load suffered by the cage structure in the marine environment, and their magnitudes and directions change with time.

[0241] In addition, it should be noted that based on the initial time-step velocity, the initial conditions of the dynamic analysis can conform to the actual situation, thereby improving the accuracy of the dynamic response analysis. Reasonably selecting the time step can achieve a balance between computational accuracy and computational efficiency, ensuring the high efficiency and reliability of the dynamic analysis, and comprehensively evaluating the motion state of the cage structure under the action of the cage dynamic load. By accurately calculating the wave force, the wind force, and the flow force, the dynamic response of the cage structure in a complex marine environment can be comprehensively evaluated, and areas with excessive deformation or stress concentration that may occur can be identified. This helps to optimize the design of the cage structure, improve its ability to resist the cage dynamic load, extend the service life, reduce the maintenance cost, and enhance the overall economic benefits of the marine aquaculture facilities.

[0242] Step E12: Determine the cage dynamic load based on the wave force, the wind force, and the flow force;

[0243] It should be noted that the cage dynamic load reflects the characteristics of the external force acting on the cage structure in the marine environment that changes with time.

[0244] It is understandable that the cage dynamic load acts on the cage structure. By reasonably dealing with the cage dynamic load, the mechanical properties of the cage structure can be optimized, the material cost can be reduced, and the overall economic benefits of the marine aquaculture facilities can be significantly improved.

[0245] Step E13: Obtain the initial acceleration based on the cage dynamic load, the initial time-step velocity, the cage static displacement, and the information of the assembly matrix set;

[0246] It is understandable that the initial acceleration can characterize the response of the cage structure to start moving under the action of the cage dynamic load at the initial time step, reflecting the motion trend of the structure at the initial stage of the dynamic analysis.

[0247] Step E14: Determine the cage predicted displacement and the cage predicted velocity based on the time step, the initial time-step displacement, the initial time-step velocity, and the initial acceleration;

[0248] It should be noted that the predicted displacement of the cage reflects the characteristics of the displacement lengths that each node of the cage structure is expected to reach at the current time step, and the predicted velocity of the cage reflects the characteristics of the predicted movement velocities of each node of the cage structure at the current time step.

[0249] It can be understood that using the predicted displacement of the cage and the predicted velocity of the cage can effectively predict the movement state of the cage structure under the action of the cage dynamic load, and identify in advance the areas where excessive deformation or stress concentration may occur.

[0250] Step E15: Determine the time-step acceleration based on the cage dynamic load, the predicted displacement of the cage, the predicted velocity of the cage, the time step, and the information of the assembly matrix set. Calculate the time-step displacement and the time-step velocity according to the time-step acceleration, and update the predicted displacement of the cage and the predicted velocity of the cage to obtain the cage dynamic displacement.

[0251] It should be noted that the time-step displacement reflects the characteristics of the displacement changes of the cage structure within different time-step cycles, and the time-step velocity reflects the characteristics of the velocity changes of the cage structure within different time-step cycles.

[0252] It can be understood that the cage dynamic displacement can characterize the deformation behavior of the cage structure under the action of the cage dynamic load, comprehensively evaluate the response of the cage structure under the action of the cage dynamic load, so as to optimize the design of the cage structure and improve the ability to resist the cage dynamic load.

[0253] Step S23: Determine the total cage displacement based on the cage static displacement and the cage dynamic displacement.

[0254] It can be understood that the total cage displacement can characterize the actual deformation of the cage structure in a complex marine environment, so as to identify weak points, take reinforcement measures in advance, optimize the design of the cage, effectively extend the service life of the cage, reduce the maintenance cost, and significantly improve the overall economic benefits and reliability of the marine aquaculture facilities.

[0255] For the convenience of understanding, taking the determination of the total cage displacement as an example, the information acquisition device is the information acquisition module, the storage device is the memory, and the processing device is the processing module.

[0256] The information acquisition module obtains the cage static displacement U_static, obtains the cage dynamic displacement U_dynamic, and determines the total cage displacement based on the cage static displacement and the cage dynamic displacement, that is, adding the static displacement and the dynamic displacement to obtain the total cage displacement U_total, which is expressed as:

[0257] U_total = U_static + U_dynamic

[0258] Perform subsequent processing based on the total displacement of the cage.

[0259] A method for evaluating the stress fatigue of an offshore truss cage structure proposed in this embodiment performs static analysis of the cage based on the cage structure load information and the assembly matrix set information to locate the load position and determine the static displacement of the cage; performs dynamic analysis of the cage based on the assembly matrix set information and the static displacement of the cage to update and iterate the displacement and determine the dynamic displacement of the cage; determines the total displacement of the cage based on the static displacement and the dynamic displacement of the cage. It solves the technical problem of how to more efficiently and accurately solve the stress of the offshore truss cage structure for stress fatigue assessment of the cage structure. Compared with the prior art, this application performs static analysis of the cage by using the cage structure load information and the assembly matrix set information, locates the load action position and determines the static displacement of the cage, and performs dynamic analysis of the cage by using the assembly matrix set information and the static displacement, updates and iterates the displacement to determine the dynamic displacement of the cage, thereby calculating the total displacement of the cage, realizing accurate assessment of the deformation state of the cage under complex loads, optimizing the cage design, improving its reliability and safety in complex marine environments, reducing maintenance costs and extending service life.

[0260] This application also provides a device for evaluating the stress fatigue of an offshore truss cage structure. Please refer to Figure 7 [[ID=�]] and the device for evaluating the stress fatigue of the offshore truss cage structure includes:

[0261] An acquisition module 10 for acquiring cage structure load information and assembly matrix set information;

[0262] A processing module 20 for performing static-dynamic coupling analysis based on the cage structure load information and the assembly matrix set information to determine the total displacement of the cage, and the static-dynamic coupling analysis includes static analysis of the cage and dynamic analysis of the cage;

[0263] An execution module 30 for calculating the stress of the cage structure according to the total displacement of the cage and the assembly matrix set information, and predicting the fatigue life of the cage to complete the stress fatigue assessment of the cage structure.

[0264] The acquisition module 10 is further configured to acquire a user configuration file and an initialization matrix set;

[0265] Call a programming function to read the user configuration file to obtain cage structure load information, and the cage structure load information includes node coordinate information, element connection information, material parameter information, load information, support information, and specified displacement information;

[0266] Initialize the initialization matrix set to adjust the initial value, and transform the coordinate system for matrix assembly to obtain assembly matrix set information, and the assembly matrix set information includes a global stiffness matrix, a global mass matrix, and a global damping matrix.

[0267] The processing module 20 is further configured to perform static analysis of the cage based on the cage structure load information and the assembly matrix set information to locate the load position and determine the static displacement of the cage.

[0268] Perform dynamic analysis of the cage based on the assembly matrix set information and the static displacement of the cage to update and iterate the displacement, and determine the dynamic displacement of the cage.

[0269] Determine the total displacement of the cage based on the static displacement and the dynamic displacement of the cage.

[0270] The processing module 20 is further configured to obtain the support type information, which includes rigid supports, elastic supports, and inclined supports.

[0271] Modify the global stiffness matrix in the assembly matrix set information based on the support type information to determine the modified stiffness matrix.

[0272] Locate the specified displacement of the nodes based on the cage structure load information and the modified stiffness matrix, and quantify the row and column values of the load contribution adjustment matrix to determine the updated load vector and the updated stiffness matrix.

[0273] Obtain the static displacement of the cage based on the updated load vector and the updated stiffness matrix.

[0274] The processing module 20 is further configured to obtain the time step, the initial time step displacement, the initial time step velocity, the wave force, the wind force, and the current force.

[0275] Determine the dynamic load of the cage based on the wave force, the wind force, and the current force.

[0276] Obtain the initial acceleration based on the dynamic load of the cage, the initial time step velocity, the static displacement of the cage, and the assembly matrix set information.

[0277] Determine the predicted displacement and the predicted velocity of the cage based on the time step, the initial time step displacement, the initial time step velocity, and the initial acceleration.

[0278] Determine the acceleration at the time step based on the dynamic load of the cage, the predicted displacement of the cage, the predicted velocity of the cage, the time step, and the assembly matrix set information, calculate the displacement and velocity at the time step according to the acceleration at the time step, and update the predicted displacement and the predicted velocity of the cage to obtain the dynamic displacement of the cage.

[0279] The execution module 30 is further configured to determine the support reaction force according to the total displacement of the cage and the global stiffness matrix in the assembly matrix set information.

[0280] Extract the node displacement vector based on the total displacement of the cage, and transform the global stiffness matrix in the information of the assembled matrix set to determine the set of axial forces of the members;

[0281] Calculate the set of member stresses based on the set of axial forces of the members and the cross-sectional areas of the members;

[0282] Extract key members based on the set of member stresses for the fatigue life assessment of the cage, and determine the fatigue life assessment result of the cage;

[0283] Predict the fatigue life of the cage based on the total displacement of the cage, the reaction force of the support, the set of axial forces of the members, the set of member stresses, and the fatigue life assessment result of the cage to complete the fatigue assessment of the cage structure under force.

[0284] The execution module 30 is further configured to extract the deformation degree of the key members based on the set of member stresses, and extract the lengths of the key members to calculate the time history of the member stresses;

[0285] Analyze the time history of the member stresses to extract the stress amplitude, and determine the number of cycles and the fatigue life;

[0286] Calculate the cumulative damage based on the number of cycles and the fatigue life, and perform the fatigue life assessment of the cage based on the cumulative damage to obtain the fatigue life assessment result of the cage.

[0287] The device for fatigue assessment of the force on the marine truss cage structure provided by the present application adopts the method for fatigue assessment of the force on the marine truss cage structure in the above embodiment, and can solve the technical problem of how to more efficiently and accurately solve the force on the marine truss cage structure for the fatigue assessment of the cage structure under force. Compared with the prior art, the beneficial effects of the device for fatigue assessment of the force on the marine truss cage structure provided by the present application are the same as those of the method for fatigue assessment of the force on the marine truss cage structure provided by the above embodiment, and other technical features in the device for fatigue assessment of the force on the marine truss cage structure are the same as the features disclosed in the method of the above embodiment, and will not be elaborated here.

[0288] The present application provides a device for fatigue assessment of the force on a marine truss cage structure. The device for fatigue assessment of the force on a marine truss cage structure includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein, the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method for fatigue assessment of the force on the marine truss cage structure in the first embodiment above.

[0289] Next, refer to Figure 8, which shows a schematic structural diagram of a device for evaluating the mechanical fatigue of an ocean truss-type cage structure suitable for implementing the embodiments of the present application. The device for evaluating the mechanical fatigue of an ocean truss-type cage structure in the embodiments of the present application may include, but is not limited to, mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), in-vehicle terminals (such as in-vehicle navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Figure 8 The shown device for evaluating the mechanical fatigue of an ocean truss-type cage structure is merely an example and should not impose any limitations on the functions and scope of use of the embodiments of the present application.

[0290] As Figure 8 shown, the device for evaluating the mechanical fatigue of an ocean truss-type cage structure may include a processing device 1001 (such as a central processing unit, a graphics processing unit, etc.), which may perform various appropriate actions and processes according to a program stored in a ROM (Read Only Memory) 1002 or a program loaded from a storage device 1003 into a RAM (Random Access Memory) 1004. In the RAM 1004, various programs and data required for the operation of the device for evaluating the mechanical fatigue of an ocean truss-type cage structure are also stored. The processing device 1001, the ROM 1002, and the RAM 1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Generally, the following systems may be connected to the I / O interface 1006: an input device 1007 including, for example, a touch screen, a touchpad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; an output device 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; a storage device 1003 including, for example, a magnetic tape, a hard disk, etc.; and a communication device 1009. The communication device 1009 may allow the device for evaluating the mechanical fatigue of an ocean truss-type cage structure to communicate with other devices wirelessly or wiredly to exchange data. Although the figure shows a device for evaluating the mechanical fatigue of an ocean truss-type cage structure having various systems, it should be understood that it is not required to implement or have all the shown systems. More or fewer systems may be alternatively implemented or had.

[0291] In particular, according to the embodiments disclosed in the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, the embodiments disclosed in the present application include a computer program product that includes a computer program carried on a computer-readable medium, and the computer program contains program codes for executing the methods shown in the flowcharts. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by a processing device 1001, the above-mentioned functions defined in the methods of the embodiments disclosed in the present application are executed.

[0292] The force fatigue assessment device for a marine truss cage structure provided by the present application adopts the force fatigue assessment method for a marine truss cage structure in the above-mentioned embodiment, and can solve the technical problem of how to more efficiently and accurately solve the force of a marine truss cage structure for force fatigue assessment of the cage structure. Compared with the prior art, the beneficial effects of the force fatigue assessment device for a marine truss cage structure provided by the present application are the same as those of the force fatigue assessment method for a marine truss cage structure provided by the above-mentioned embodiment, and other technical features in the force fatigue assessment device for a marine truss cage structure are the same as the features disclosed in the method of the previous embodiment, and will not be elaborated here.

[0293] It should be understood that the various parts disclosed in the present application can be implemented by hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0294] As described above, the above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, and all should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0295] The present application provides a computer-readable storage medium with computer-readable program instructions (i.e., computer programs) stored thereon, and the computer-readable program instructions are used to execute the force fatigue assessment method for a marine truss cage structure in the above-mentioned embodiment.

[0296] The computer-readable storage medium provided by this application can be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or components, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM) or flash memory, optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In this embodiment, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, device, or component. The program code contained on the computer-readable storage medium can be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0297] The above computer-readable storage medium can be included in the fatigue assessment device for the mechanical stress of an offshore truss cage structure; or it can exist independently without being assembled into the fatigue assessment device for the mechanical stress of an offshore truss cage structure.

[0298] The above computer-readable storage medium carries one or more programs. When the one or more programs are executed by the fatigue assessment device for the mechanical stress of an offshore truss cage structure, the fatigue assessment device for the mechanical stress of an offshore truss cage structure is caused to: obtain the load information of the cage structure and the information of the assembly matrix set; perform static-dynamic coupling analysis based on the load information of the cage structure and the information of the assembly matrix set to determine the total displacement of the cage. The static-dynamic coupling analysis includes static analysis of the cage and dynamic analysis of the cage; calculate the mechanical stress of the cage structure according to the total displacement of the cage and the information of the assembly matrix set, and predict the fatigue life of the cage to complete the fatigue assessment of the cage structure's mechanical stress.

[0299] Computer program code for performing the operations of this application can be written in one or more programming languages or combinations thereof. The above-mentioned programming languages include object-oriented programming languages such as Java, Smalltalk, C++, and also include conventional procedural programming languages such as the "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, executed as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any kind of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, by connecting through the Internet using an Internet service provider).

[0300] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a part of code that contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than that marked in the accompanying drawings. For example, two consecutively represented blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0301] The modules described in the embodiments of this application can be implemented in software or in hardware. Among them, the name of the module does not constitute a limitation to the unit itself in some cases.

[0302] The readable storage medium provided by this application is a computer-readable storage medium. The computer-readable storage medium stores computer-readable program instructions (i.e., computer programs) for performing the above-mentioned method for fatigue assessment of the mechanical stress of an ocean truss cage structure, and can solve the technical problem of how to more efficiently and accurately solve the mechanical stress of the ocean truss cage structure for fatigue assessment of the cage structure. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided by this application are the same as those of the method for fatigue assessment of the mechanical stress of the ocean truss cage structure provided in the above embodiments, and will not be elaborated here.

[0303] The above are only some embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structural transformation made under the technical concept of the present application by using the content of the specification and drawings of the present application, or directly / indirectly applied to other related technical fields, is included in the patent protection scope of the present application.

Claims

1. A method for evaluating the mechanical fatigue of an ocean truss-type cage structure, characterized in that The method includes: Obtain cage structure load information and assembly matrix set information; Performing a static-dynamic coupling analysis based on the cage structure load information and the assembly matrix set information to determine the total displacement of the cage, wherein the static-dynamic coupling analysis includes a cage static analysis and a cage dynamic analysis; The stress on the cage structure is calculated based on the total displacement of the cage and the assembly matrix set information, and the fatigue life of the cage is predicted to complete the stress fatigue assessment of the cage structure.

2. The method according to claim 1, characterized in that The steps of obtaining cage structure load information and assembling matrix set information include: Get the user profile and initialization matrix set; Calling a programming function to read the user configuration file to obtain the cage structure load information, wherein the cage structure load information includes node coordinate information, unit connection information, material parameter information, load information, support information, and specified displacement information; Initializing the initialization matrix set to adjust the initial value, and transforming the coordinate system to perform matrix assembly to obtain assembly matrix set information, wherein the assembly matrix set information includes a global stiffness matrix, a global mass matrix, and a global damping matrix.

3. The method according to claim 1, wherein The step of performing static and dynamic coupling analysis based on the cage structure load information and the assembly matrix set information to determine the total displacement of the cage includes: Performing a static analysis of the cage to locate the load position based on the cage structure load information and the assembly matrix set information, and determining the cage static displacement; Performing dynamic analysis of the cage based on the assembly matrix set information and the cage static displacement to update the iterative displacement and determine the cage dynamic displacement; The total displacement of the cage is determined based on the static displacement of the cage and the dynamic displacement of the cage.

4. The method according to claim 3, wherein The step of performing static analysis on the cage to locate the load position and determine the static displacement of the cage based on the cage structure load information and the assembly matrix set information comprises: Acquiring support type information, wherein the support type information includes rigid support, elastic support, and inclined support; Correcting the global stiffness matrix in the assembly matrix set information based on the support type information to determine a corrected stiffness matrix; Positioning node prescribed displacements based on the cage structure load information and the modified stiffness matrix, and quantifying load contribution adjustment matrix row and column values to determine updated load vectors and updated stiffness matrices; The static displacement of the cage is obtained based on the updated load vector and the updated stiffness matrix.

5. The method according to claim 3, wherein The step of performing dynamic analysis and iterative displacement updating of the cage based on the assembly matrix set information and the cage static displacement to determine the cage dynamic displacement comprises: Get the time step, initial time step displacement, initial time step velocity, wave force, wind force and flow force; determining a dynamic load of the cage based on the wave force, the wind force, and the current force; Obtaining an initial acceleration based on the cage dynamic load, the initial time step velocity, the cage static displacement and the assembly matrix set information; determining a predicted displacement of the cage and a predicted velocity of the cage based on the time step, the initial time step displacement, the initial time step velocity, and the initial acceleration; The time step acceleration is determined based on the dynamic load of the cage, the predicted displacement of the cage, the predicted speed of the cage, the time step and the assembly matrix set information, the time step displacement and the time step speed are calculated according to the time step acceleration, and the predicted displacement and the predicted speed of the cage are updated to obtain the dynamic displacement of the cage.

6. The method according to claim 1, wherein The step of calculating the cage structure stress according to the cage total displacement and the assembly matrix set information, and predicting the cage fatigue life to complete the cage structure stress fatigue assessment includes: Get the cross-sectional area of the rod; Determining the support reaction force according to the total displacement of the cage and the global stiffness matrix in the assembly matrix set information; Extracting node displacement vectors based on the total displacement of the cage, and transforming the global stiffness matrix in the assembly matrix set information to determine the rod axial force set; Calculating a rod stress set based on the rod axial force set and the cross-sectional area of the rod; Extract key rods based on the rod stress set to perform cage fatigue life assessment, and determine cage fatigue life assessment results; The cage fatigue life is predicted based on the total displacement of the cage, the support reaction force, the rod axial force set, the rod stress set and the cage fatigue life assessment result to complete the cage structure stress fatigue assessment.

7. The method according to claim 6, characterized in that The steps of extracting key rods based on the rod stress set to perform cage fatigue life assessment and determining the cage fatigue life assessment result include: Extracting the deformation degree of key members based on the member stress set, and extracting the key member length to calculate the member stress time history; Analyzing the stress time history of the rod to extract the stress amplitude and determine the number of cycles and fatigue life; The cumulative damage is calculated based on the number of cycles and the fatigue life, and the cage fatigue life is evaluated based on the cumulative damage to obtain a cage fatigue life evaluation result.

8. An apparatus for evaluating the stress fatigue of an ocean truss-type cage structure, characterized in that, The device comprises: An acquisition module is used to obtain the cage structure load information and assembly matrix set information; a processing module, configured to perform a static-dynamic coupling analysis based on the cage structure load information and the assembly matrix set information to determine the total displacement of the cage, wherein the static-dynamic coupling analysis includes a cage static analysis and a cage dynamic analysis; The execution module is used to calculate the stress of the cage structure according to the total displacement of the cage and the assembly matrix set information, and predict the fatigue life of the cage to complete the stress fatigue evaluation of the cage structure.

9. An equipment for stress fatigue assessment of an ocean truss type cage structure, characterized in that, The device includes: a memory, a processor, and a determination program stored in the memory and executable on the processor, wherein the determination program is configured to implement the steps of the stress fatigue assessment method for an offshore truss cage structure according to any one of claims 1 to 7.

10. A storage medium, characterized in that, The storage medium is a determination machine readable storage medium, and a determination machine program is stored on the storage medium. When the determination machine program is executed by the processor, the steps of the marine truss cage structure stress fatigue assessment method according to any one of claims 1 to 7 are implemented.

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