Floating platform and method for calculating pile holding force of structure and readable storage medium

Abstract

The present application relates to the technical field of general pile holding force, and proposes a floating platform and a structural pile holding force calculation method and a readable storage medium, which can efficiently and accurately calculate the general pile holding force, dynamically and accurately simulate the contact force and friction force between the clamping ring and the guide column in the three-dimensional space, and is suitable for various floating platforms and structures. The method comprises the following steps: S100: inputting the ring parameter, column parameter and friction parameter of the model structure; S200: calculating the contact force; S300: calculating the friction force; S400: outputting the pile holding force, which is further used for dynamic simulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of general pile-holding force, in particular, to a floating platform and a structure pile-holding force accurate calculation method based on dynamic contact theory and improved friction model and a readable storage medium. BACKGROUND

[0002] Floating platforms and various marine structures are widely used in shipbuilding, offshore oil and gas development, offshore wind power, and marine aquaculture. Such structures are usually fixed in place by pile-holding connection devices to resist environmental forces such as wind, waves, and currents, ensuring stability and safety during operation. Pile-holding connection devices are generally composed of guide columns (including bases) and clamps, with guide columns connected to the platform body and clamps fixed to other support structures. The contact force and friction force between the clamp and the guide column (i.e., the pile-holding force) are key factors in structural stability.

[0003] In actual working conditions, floating platforms and related structures are subjected to the combined action of various environmental forces, including wind, water flow, and wave forces. These forces not only act directly on the structure, but also indirectly affect the size and direction of the pile-holding force by causing dynamic motion of the structure (such as translation and rotation). Therefore, accurately calculating the pile-holding force under complex environmental forces is of great significance for the design of clamps and guide columns, structural stability assessment, and operational safety.

[0004] Currently, there are two main methods for calculating the pile-holding force of floating platforms and structures:

[0005] 1. Specification-based calculation method: This method is based on relevant industry specifications, and calculates the horizontal components of wave force, wind force, and flow force, and then adds these forces to obtain the pile-holding force. The specific steps include: calculating the effect of each environmental force on the structure according to wave theory, wind load formula, and fluid dynamics formula, and adding the horizontal component vectors to obtain the size and direction of the pile-holding force.

[0006] 2. CFD simulation-based calculation method: This method uses computational fluid dynamics (CFD) software to simulate the motion of the structure and simulates the constraints of the clamp and guide column through secondary development to calculate the pile-holding force. The specific steps include: establishing a fluid dynamics model to simulate the dynamic motion of the structure under the action of wind, waves, and flow, and combining the constraints of the clamp and guide column to calculate the size and direction of the pile-holding force.

[0007] However, the above prior art does not fully consider the dynamic motion characteristics of the structure, and it is difficult to reflect the change rule of the pile holding force under actual working conditions; at the same time, the method based on CFD simulation has low calculation efficiency and poor engineering applicability, and it is difficult to meet the demand of efficient and rapid calculation; and there is no special calculation model for the contact behavior of the clamping ring and the guide column, which cannot accurately describe the nonlinear contact force and friction force between the two, resulting in insufficient accuracy of the pile holding force calculation. SUMMARY

[0008] One of the purposes of the present application is to provide a floating platform and structure pile holding force calculation method, which can efficiently and accurately calculate the general pile holding force, dynamically and accurately simulate the contact force and friction force between the clamping ring and the guide column in three-dimensional space, and is suitable for various floating platforms and structures.

[0009] The technical solution of the present application is as follows:

[0010] A floating platform and structure pile holding force calculation method, comprising the following steps:

[0011] S100: Establish a three-dimensional geometric model, input the circular ring parameters, column parameters and friction parameters of the model structure;

[0012] S200: Calculate the contact force ;

[0013] S300: Calculate the friction force using a dynamic friction force model ;

[0014] S400: Output the pile holding force: .

[0015] Further, step S200 comprises:

[0016] S210: Taking the circular ring as the reference system and the column as the moving body, calculate the position vector of the column center relative to the circular ring center ;

[0017] S220: Calculate the three-dimensional rotation matrix according to the Euler angle of the circular ring, which is used to convert the direction vector of the circular ring local coordinate system to the global coordinate system and reflect the spatial posture of the circular ring;

[0018] S230: Calculate the contact point direction angle , accurately calculate the angular position of the contact point by the inverse tangent function;

[0019] S240: Calculate the local direction vector ;

[0020] S250: Calculate the global direction vector , transform the local direction vector to the global coordinate system by the rotation matrix;

[0021] S260: Calculate the ring surface point position ;

[0022] ;

[0023] S270: Calculate the column surface point position ;

[0024] S280: Calculate the contact depth ;

[0025] S290: Calculate the normal direction vector ;

[0026] ;

[0027] Calculate the relative velocity , since the ring is stationary, the column is moving, so , the relative velocity is the velocity of the column; Calculate the contact force:

[0028] If , then:

[0029] Elastic force ;

[0030] Damping force .

[0031] Total contact force , where F max is the upper limit of the contact force;

[0032] Contact force vector ;

[0033] If , there is no contact, and the contact force is zero: .

[0034] Further, step S300 includes:

[0035] S310: Calculate the relative velocity norm ;

[0036] S320: Calculate the normal force norm ;

[0037] S330: Calculate the relative velocity direction ;

[0038] where is a very small positive number to prevent division by zero;

[0039] : Relative velocity vector;

[0040] denotes the modulus of the relative velocity;

[0041] unit direction vector of the relative velocity;

[0042] when the modulus of the relative velocity is greater than a minimum value , is the unit vector of the relative velocity.

[0043] when the relative velocity is very small, in order to avoid division by zero, directly take the zero vector;

[0044] S340: Calculate the dynamic friction coefficient ;

[0045] where, , ;

[0046] , where is the characteristic velocity parameter, is the static friction coefficient, is the dynamic friction coefficient;

[0047] S350: Calculate the friction force , the direction is opposite to the relative velocity.

[0048] Further, including step S500: at each time domain step, input the current state of the circular ring and the column, and calculate in turn according to the above formula to obtain the pile holding force, which is further used for dynamic simulation, including convergence judgment and iteration optimization steps:

[0049] S510: Set the convergence criterion ;

[0050] S520: Calculate the relative error of the pile holding force between the current step and the last step:

[0051] ;

[0052] If , calculate the convergence and output the result; otherwise, update the parameters and continue iteration;

[0053] Limit the maximum number of iterations to prevent infinite loop.

[0054] Further, the three-dimensional rotation matrix in step S220 is as follows:

[0055] .

[0056] Further, the angle position of the contact point in step S230 is accurately calculated by an inverse tangent function.

[0057] Further, the angle position of the contact point in step S270 is accurately calculated by an inverse tangent function.

[0058] wherein,

[0059] Further, the angle position of the contact point in step S280 is accurately calculated by an inverse tangent function.

[0060] If , it indicates that contact occurs, and is the overlap depth.

[0061] Further, it is suitable for different marine environmental conditions, including:

[0062] Dynamic analysis under wave load, steady-state analysis under current action, transient analysis under combined load, and stability and precision of calculation are ensured by adaptive time step control.

[0063] Another purpose of the present application is to provide a readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the floating platform and structure pile-holding force calculation method described above.

[0064] The beneficial effects of the present application are:

[0065] The present application realizes coupling with the structure dynamics motion model by constructing a special contact force and friction force calculation model, and can reflect the actual stress state of the structure under the action of complex environmental forces in real time.

[0066] By improving the calculation efficiency, simplifying the modeling process, and enhancing the universality and engineering applicability of the model, various engineering needs such as structure design, stability evaluation, and operation safety analysis can be met.

[0067] By establishing dynamic contact point calculation, nonlinear contact force and friction force modeling and other modules, the mechanical behavior between the clasp ring and the column can be comprehensively and accurately simulated, the accuracy and applicability of the pile-holding force calculation are significantly improved, and the engineering needs of various floating platforms and structure dynamics analysis under complex environments can be met.

[0068] Compared with the prior art, the present application has the following significant advantages:

[0069] 1. Dynamic and accurate modeling of contact force and friction force

[0070] ​​​​The present application establishes an accurate calculation model of nonlinear contact force and friction force according to the actual contact behavior between the clamping ring and the column, can dynamically update the position and direction of the contact point in real time, and effectively simulates the change process of static friction and dynamic friction through the smooth transition of the friction coefficient. Compared with the traditional method which only uses simplified assumptions or ignores the contact behavior, the accuracy and reliability of the pile holding force calculation are greatly improved, especially suitable for dynamic analysis under complex environmental forces.

[0071] 2. High efficiency and good scalability

[0072] Using modular design, the pile holding force calculation model is independently encapsulated, which is convenient for integration with different types of dynamic simulation platforms, can flexibly adapt to various engineering scenarios (such as floating wind power, offshore platforms, etc.), and greatly improves the universality and engineering applicability of the model.

[0073] In summary, the present application is superior to the prior art in terms of calculation accuracy, efficiency and applicable range, and provides an efficient and reliable technical solution for accurate calculation of pile holding force of floating docks and similar structures. DETAILED DESCRIPTION

[0074] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0075] Embodiment 1

[0076] A floating platform and structure pile holding force calculation method is suitable for different marine environmental conditions, mechanical analysis, structural design and dynamic simulation of mooring system of various floating platforms, offshore engineering structures, floating facilities and other engineering applications. It includes dynamic analysis under wave load, steady-state analysis under current action, and transient analysis under combined load, which ensures calculation stability and accuracy through adaptive time step control.

[0077] It can solve the problem of lack of special calculation model for dynamic contact behavior between the clamping ring and the column in the prior art, which leads to insufficient calculation accuracy of the pile holding force. It also cannot accurately simulate the nonlinear contact force and friction force between the clamping ring and the column under the combined action of complex environmental forces, which affects the reliability and engineering applicability of the dynamic simulation. In addition, the existing calculation method has poor universality and is difficult to adapt to the dynamic analysis requirements of different structural parameters and variable working conditions.

[0078] Specifically, the method comprises the following steps:

[0079] S100: input the ring parameter, the column parameter and the friction parameter of the model structure, the ring parameter includes the inner diameter, the outer diameter and the thickness, the column parameter includes the radius and the position coordinate, the friction parameter includes the static friction coefficient and the dynamic friction coefficient, such as:

[0080] Ring parameter: mass m, inner diameter , centroid position (global coordinate) , Euler angle (describe the attitude of the ring) ;

[0081] Column parameter: radius , center position (global coordinate) , velocity (global coordinate) , contact stiffness k, damping coefficient c, maximum contact force ;

[0082] Friction parameter: static friction coefficient , dynamic friction coefficient , static friction speed threshold ;

[0083] S200: calculate the contact force ;

[0084] Wherein, the step S200 includes:

[0085] S210: taking the ring as the reference system and the column as the moving body, calculate the position vector of the column center relative to the ring center ;

[0086] S220: according to the Euler angle of the ring , calculate the three-dimensional rotation matrix , which is used to convert the direction vector of the ring local coordinate system to the global coordinate system, reflecting the spatial attitude of the ring; ;

[0087] If there is a special rotation order (such as ZYX, XYZ, etc.), it can be adjusted according to the actual engineering definition.

[0088] S230: calculate the contact 1 point direction angle ;

[0089] The above .

[0090] This is the polar angle of the column center relative to the ring center in the XY plane, which determines the direction of the point closest to the column on the inner surface of the ring.

[0091] S240: calculate the local direction vector ;

[0092] This is the unit vector pointing to the contact point in the local coordinate system of the ring.

[0093] S250: Calculate the global direction vector , transform the local direction vector to the global coordinate system by the rotation matrix;

[0094] S260: Calculate the position of the ring surface point ;

[0095] ;

[0096] This is the spatial coordinate of the point on the inner surface of the ring closest to the column.

[0097] S270: Calculate the position of the column surface point ;

[0098] The above ;

[0099] Where, .

[0100] Ensure that the column surface point and the ring surface point are consistent in the XY plane direction and have the same Z coordinate.

[0101] Defects in the prior art: both the specification and the CFD method ignore the precise geometric contact relationship between the snap ring and the guide column, and only consider the overall structural stress.

[0102] This embodiment establishes a precise geometric positioning algorithm for the contact point between the ring and the column through this step, realizes dynamic tracking of the real contact point, and improves the contact force calculation accuracy compared with traditional overall structure analysis

[0103] S280: Calculate the contact depth ;

[0104] The above ;

[0105] If , it means that contact has occurred, and is the overlap depth.

[0106] If necessary, a minimum contact depth threshold can be set to avoid false contact caused by numerical errors.

[0107] The blind spot of the prior art is that the specification method and CFD simulation cannot accurately describe the dynamic change of the contact depth. Therefore, this embodiment establishes a precise contact depth model based on geometric distance, and introduces a minimum contact depth threshold.

[0108] S290: Calculate the normal direction vector ;

[0109] ;

[0110] This is the unit vector from the ring surface point to the column surface point.

[0111] Calculate relative velocity Since the ring is stationary, the column is moving, so The relative velocity is the velocity of the column; denotes the absolute velocity of the column;

[0112] Calculate the contact force:

[0113] If Contact occurs, 1 nonlinear characteristics;

[0114] The limitations of the prior art are as follows:

[0115] Specification method: linear superposition is used, and the contact nonlinearity is ignored;

[0116] CFD method: Although it can simulate fluid nonlinearity, the contact modeling is still relatively simple;

[0117] This embodiment first introduces the 1.5 nonlinear of Hertz contact theory in the calculation of the holding pile force, which can accurately describe the material response under large contact pressure compared with the linear model.

[0118] Damping force Only the normal velocity component is considered.

[0119] Total contact force Where is the upper limit of the contact force to prevent the contact force from being too large, causing numerical instability or structural damage.

[0120] Contact force vector ;

[0121] If There is no contact, and the contact force is zero: .

[0122] S300: Calculate the friction force using a dynamic friction force model ;

[0123] The dynamic friction force model considers the effect of relative velocity change on the friction coefficient;

[0124] Wherein, step S300 comprises:

[0125] S310: Calculate the norm of the relative velocity ;

[0126] : Relative velocity vector;

[0127] S320: Calculate the norm of the normal force ;

[0128] S330: Calculate the relative velocity direction ;

[0129] where, is a very small positive number to prevent division by zero;

[0130] denotes the norm of the relative velocity;

[0131] When the norm of the relative velocity is greater than a very small value , is the unit vector of the relative velocity (i.e. direction).

[0132] When the relative velocity is very small (tends to zero), in order to avoid division by zero, take the zero vector;

[0133] S340: Calculate the dynamic friction coefficient ;

[0134] where, is a very small positive number to prevent division by zero; ;

[0135] is a very small positive number to prevent division by zero; , where is a characteristic velocity parameter, is the static friction coefficient, is the dynamic friction coefficient;

[0136] The defects of the prior art are as follows:

[0137] Normative method: completely ignore the friction effect or use a fixed friction coefficient;

[0138] CFD method: friction modeling is simplified and cannot handle static-dynamic friction conversion;

[0139] The embodiment creatively uses an exponential function to realize the smooth transition of static-dynamic friction, eliminating numerical oscillation caused by sudden changes in friction, and improving stability.

[0140] S350: Calculate the friction force , the direction is opposite to the relative velocity.

[0141] The direction is opposite to the direction of the relative velocity, and the size is proportional to the normal force and the friction coefficient.

[0142] S400: Output the holding force: ;

[0143] The total holding force is the vector sum of the contact force (normal force) and the friction force (tangential force).

[0144] The total pile-holding force acting on the column is obtained by adding the two together.

[0145] The dynamic friction model in this embodiment adaptively adjusts the friction coefficient based on the relative speed, realizing real-time tracking of the friction characteristics.

[0146] S500: At each time domain step, the current state of the circular ring and the column is input, and the pile-holding force is calculated in sequence according to the above formula, which is then used for dynamic simulation, including convergence judgment and iterative optimization steps:

[0147] S510: Set the convergence criterion to ensure that the calculation accuracy meets the engineering design requirements and avoids excessive iteration waste;

[0148] S520: Calculate the relative error of the pile-holding force between the current step and the previous step: which realizes relative error calculation, avoids criterion failure under small / large force values, guarantees engineering-level precision and prevents unnecessary iteration.

[0149] If , calculate the convergence and output the result; otherwise, update the parameters and continue iteration;

[0150] Limit the maximum number of iterations to prevent infinite loops in abnormal working conditions.

[0151] The core points of this embodiment are as follows:

[0152] 1. Construction of a general pile-holding force calculation model:

[0153] A pile-holding force calculation method suitable for various floating platforms and structures is provided, which can accurately describe the dynamic contact relationship between the clamping ring and the column in three-dimensional space. This model considers the mass center position, spatial attitude (Euler angle) of the circular ring (clamping ring), spatial position and velocity of the column, etc. parameters, realizes dynamic real-time updating of the contact point position and direction, and is suitable for dynamic simulation environment in any time domain.

[0154] Geometric calculation uses an analytical method instead of a numerical method, which improves efficiency compared to the CFD method.

[0155] 2. Real-time calculation method of dynamic contact point and direction:

[0156] The contact point and contact direction calculation method based on spatial geometric relationship is innovatively proposed, which can determine the closest contact point and its normal and tangential directions in real time according to the relative position and attitude change of the circular ring and the column, ensuring the accuracy and timeliness of the contact force and friction force calculation.

[0157] S260-S280: A complete contact point positioning → contact depth calculation chain is established.

[0158] 3. Nonlinear precise modeling of contact force and friction:

[0159] A normal contact force model based on contact depth and relative velocity is established, considering elastic force (Hertz nonlinear characteristics) and damping force, and setting a maximum contact force threshold to prevent structural failure. The friction force model uses a smooth transition algorithm of static friction coefficient, dynamic friction coefficient and static friction velocity threshold, which can accurately simulate the friction behavior between the snap ring and the column, avoid sudden changes in friction force, and improve simulation stability.

[0160] 4. Universality and scalability suitable for various engineering scenarios:

[0161] This method has high parameterization degree and is suitable for different sizes and attitudes of ring and column combination, which can be flexibly integrated into various floating platforms and structural dynamics simulation platforms, and has good universality and engineering applicability.

[0162] Example 2

[0163] The difference between this embodiment and embodiment 1 is that in addition to using the nonlinear contact force and friction force model based on contact depth and relative velocity, other contact mechanics theories such as linear spring-damper model, Penalty method, finite element contact algorithm, etc. can be used to model the contact behavior between the snap ring and the column, and realize the dynamic calculation of the holding force.

[0164] Example 3

[0165] The difference between this embodiment and embodiment 1 is that in addition to real-time calculation of contact point and direction through spatial geometric relationship, discrete method such as discretizing ring and column surface into multiple nodes, detecting contact state node by node, or determining contact point and direction based on sensor / monitoring data can be used.

[0166] Example 4

[0167] The difference between this embodiment and embodiment 1 is that in addition to using exponential smooth transition, other mathematical methods such as piecewise linear interpolation, hyperbolic tangent function, etc. can be used to realize the smooth transition between static friction and dynamic friction, and avoid sudden changes in friction force.

[0168] Example 5

[0169] The embodiment is different from embodiment 1 in that, in addition to being directly coupled with the existing dynamic simulation platform, the dynamic analysis of the bollard pull of the floating dock can also be realized through a self-defined simulation module, co-simulation or multi-body dynamic software (such as ADAMS, Simpack, etc.).

[0170] Embodiment 6

[0171] The embodiment is different from embodiment 1 in that, in addition to directly inputting the geometric and dynamic parameters of the circular ring and the column, the relevant input can also be obtained through database calling, parameterized modeling or parameter prediction based on machine learning, so as to realize the automatic and intelligent calculation of the bollard pull.

[0172] Embodiment 7

[0173] The embodiment provides a readable storage medium, which stores a computer program, and when the program is executed by a processor, the bollard pull calculation method of the floating platform and structure in each of the above embodiments is realized.

[0174] The above is only a preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for calculating the pile holding force of a floating platform and structure, characterized by, It is suitable for different marine environment conditions, including dynamic analysis under wave load, steady-state analysis under current action, transient analysis under combined load, and calculation stability and precision are ensured through adaptive time step control; including the following steps: S100: establishing a three-dimensional geometric model, inputting ring parameter, column parameter and friction parameter of the model structure; S200: Contact point and contact direction calculation method based on spatial geometric relationship, calculate contact force ; Step S200 includes: S210: Taking the circular ring as a reference system and the column as a moving body, a position vector of the column center relative to the circular ring center is calculated ; wherein, is the global coordinate vector of the circle centroid position; global coordinate vector for the column center; S220: Calculate a three-dimensional rotation matrix according to the Euler angles of the torus for converting the direction vector of the torus local coordinate system to the global coordinate system, reflecting the spatial pose of the torus; S230: Calculate the contact point direction angle ; The angle position of the contact point is accurately calculated by an inverse tangent function. S240: Calculate local direction vector ; S250: Calculate global direction vector transform the local direction vector to the global coordinate system by a rotation matrix; S260: Calculate the circular ring surface point position ; ； Ri is the inner diameter of the ring; S270: Calculate column surface point position ; ； wherein ; S280: Calculate depth of contact ; ； R is the radius of the post; If represents that contact has occurred, and overlap depth; Setting a minimum contact depth threshold to avoid false contact caused by numerical error; S290: Calculate the normal direction vector ; ； The relative velocity is the velocity of the column. Since the ring is stationary, the column moves, so The relative velocity is the velocity of the column. The absolute velocity of the column is represented. Calculating contact force: If then: elastic force ; Damping force ; total contact force wherein is the contact force upper limit, a maximum contact force threshold is set to prevent structural failure; Contact force ; If then there is no contact and the contact force is zero: ; S300: Calculate the friction force using the dynamic friction model ; S400: outputting the pile-holding force: ; S500: at each time domain step, input the current ring and column state, calculate in turn according to steps S100-S400, get the pile holding force, and then used for dynamic simulation, including convergence judgment and iteration optimization steps: S510: setting a convergence criterion ; S520: calculate the relative error of the current step and the last step pile holding force: ； If then the calculation converges and the result is output; otherwise the parameters are updated and the iteration continues. limiting the maximum number of iterations prevents infinite loops.

2. The method of claim 1, wherein, Step S300 includes: S310: Calculate the relative speed norm ; a modulus representing the relative velocity; S320: Calculate the norm of the normal force ; S330: Calculate relative speed direction ; wherein is a very small positive number, preventing division by zero; when the modulus of the relative velocity is greater than a minimum value is the unit vector of the relative velocity;​ When the relative speed is very small, in order to avoid division by zero, Directly take the zero vector; S340: calculate the dynamic friction coefficient ; wherein at a time, ; Time, wherein is a characteristic velocity parameter, is a static friction coefficient, is a dynamic friction coefficient; S350: Calculate friction force , the direction is opposite to the relative velocity.

3. A readable storage medium, characterized by, A computer program is stored thereon, which, when executed by a processor, implements the floating platform and structure pile holding force calculation method of any one of claims 1-2.

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