A cabin dynamic ballast method for float-over operation model test

Abstract

The application discloses a cabin dynamic ballast method for float-over operation model test, and relates to the technical field of ocean engineering, and comprises the following steps: S1: obtaining the finite element model, mass parameters and barycentric coordinates of a barge empty model, obtaining the finite element model, unballasted mass and barycentric coordinates of a barge cabin model, and calculating the initial mass and barycentric coordinates of the float-over operation barge; S2: setting predetermined ballast parameters of the float-over operation barge; S3: setting a barge positive float target optimization function, a maximum inertia moment target optimization function and a draft target optimization function, and setting a constraint condition; S4: calculating the mass of ballast water in each cabin at each time through an optimization algorithm, and performing ballast control; S5: obtaining the mass increased in each cabin during the ballast process, calculating the mass and barycentric coordinates of the float-over operation barge ballast process, and returning to S4. The method can realize continuous simulation of load transfer in the float-over operation process in the physical model test.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ocean engineering, and particularly relates to a cabin dynamic ballast method for a float-over operation model test. BACKGROUND

[0002] With the development and utilization of ocean resources / energy gradually moving towards the deep sea, the large-scale and intensive trend of the infrastructure for the development and utilization of ocean resources / energy such as offshore platforms and offshore wind power is increasingly obvious. The weight of some ocean engineering structures reaches tens of thousands of tons, which exceeds the operation capacity of traditional offshore floating cranes, resulting in that the traditional offshore hoisting operation method is no longer applicable, and the float-over operation method which is not sensitive to the weight of the structure becomes the mainstream method for the installation of super-large ocean engineering structures.

[0003] The pool model test is the most direct and effective method for verifying the feasibility and safety of the float-over operation scheme. In the actual continuous load transfer process of the float-over operation, the ballast water is continuously injected into the cabin of the float-over operation barge to continuously increase the draft of the float-over operation barge, and at the same time, the position of the upper block connected to the float-over operation barge is lowered to realize the gradual transfer of the weight of the upper block from the float-over barge to the foundation structure. However, the existing pool model test usually simulates the entire load transfer process by discretizing it into several stable states, which does not conform to the actual situation of the continuous load transfer operation of the float-over operation.

[0004] In view of this, the present application is proposed. SUMMARY

[0005] The present application aims to solve the problems in the prior art and provides a cabin dynamic ballast method for a float-over operation model test, which can realize continuous simulation of the load transfer in the float-over operation process in the physical model test.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] A cabin dynamic ballast method for a float-over operation model test, comprising the following steps:

[0008] S1: obtaining the finite element model, mass parameters and center of gravity coordinates of the barge empty ship model, obtaining the finite element model, unloaded mass and center of gravity coordinates of the barge cabin model, and calculating the initial mass and center of gravity coordinates of the float-over operation barge;

[0009] S2: setting the predetermined ballast parameters of the float-over operation barge;

[0010] S3: setting the barge positive float target optimization function, the maximum moment of inertia target optimization function and the draft amount target optimization function, and setting the constraint conditions;

[0011] S4: Calculate the mass of ballast water in each compartment at each time point using an optimization algorithm, and perform ballast control.

[0012] S5: Obtain the mass increase of each compartment during ballasting, calculate the mass and center of gravity coordinates of the ballasting barge during the floating operation, and return to S4.

[0013] Furthermore, in step S1, the initial mass and center of gravity coordinates of the towing barge are calculated using the following formula:

[0014] ;

[0015] ;

[0016] ;

[0017] ;

[0018] In the formula, The initial mass of the barge used for the tugboat operation. For the quality of the empty barge model, For the first The mass of each compartment when it is not ballasted For the number of cabins, , , These are the initial center of gravity coordinates of the barge during the floating overhaul operation when the compartments are not ballasted. , , These are the coordinates of the center of gravity of the empty barge model. , , The first The center of gravity coordinates of each compartment when it is not ballasted.

[0019] Furthermore, in step S5, the mass and center of gravity coordinates of the ballast vessel during the overloading operation are calculated using the following formula:

[0020] ;

[0021] ;

[0022] ;

[0023] ;

[0024] In the formula, The mass of the barge used for ballast operations at time t is given. When the ballast is carried out to the tth time Ballast mass of each compartment , , Ballasting to The coordinates of the center of gravity of the barge used for floating overboard operations. , , When the ballast is carried out to the tth time The coordinates of the center of gravity of each compartment.

[0025] Furthermore, in S2, the predetermined ballast parameters of the floating barge include: the initial draft of the barge, the draft during the docking process, and the draft during the withdrawal stage.

[0026] Furthermore, in S3, the target optimization functions for barge buoyancy, maximizing moment of inertia, and ballast volume, as well as the constraints, are as follows:

[0027] m;

[0028] ;

[0029] kg;

[0030] ;

[0031] In the formula, Ballasting to Time The total mass of ballast water in each compartment The mass of the barge used for ballast operations at time t is given. It is the acceleration due to gravity. Ballasting The coordinates of the center of gravity of the barge used for floating overboard operations. For the process After ballast The mass increase of each compartment, Δt is the time interval. Ballasting The target value of the center of gravity coordinates of the barge used in the floating overhaul operation. For the barge's rolling moment of inertia, , These are the times when the ballast is carried out (t). The coordinates of the center of gravity of each compartment , , The first The length, width, and height of each compartment Ballasting The target quality of the floating barge during the time-to-float operation This is the density of the ballast water.

[0032] Further, in the S4, a second generation non-dominated sorting genetic algorithm is used to solve a multi-objective optimization function to calculate the mass of ballast water in each cabin.

[0033] Compared with the prior art, the present application has the following advantages:

[0034] 1. In the water tank model, it can be used for complete reproduction of the continuous simulation of load transfer in the float-over operation, and thus the potential risks of the float-over operation can be accurately captured, which is of great significance to the safety of the float-over operation system.

[0035] 2. At the initial stage, the ballast scheme is determined by S4, i.e. the total mass of ballast water in each cabin at each time during ballast, during the ballast process, S5 is executed through real-time feedback data and returns to S4, and the mass of ballast water in each cabin at each subsequent time is fine-tuned, so as to realize the continuous simulation of load transfer in the float-over operation and improve the accuracy and efficiency of the simulation of the float-over operation model test. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a schematic diagram of the barge structure for float-over operation.

[0037] Figure 2 It is a flowchart of the cabin dynamic ballast method for float-over operation model test.

[0038] Figure 3 It is the mass change curve of the ballast water in the cabins 1, 2P-8P at each time obtained by optimization.

[0039] Figure 4 It is the mass change curve of the ballast water in the cabins 2S-8S at each time obtained by optimization.

[0040] Figure 5 It is the vertical coordinate change curve of the center of gravity of the float-over operation barge at each time during the ballast process.

[0041] Figure 6 It is the vertical coordinate change curve of the center of gravity of the upper block at each time during the ballast process.

[0042] Figure 7 It is the stress curve of the deck support structure (DSU) at each time during the ballast process.

[0043] Figure 8 It is the stress curve of the leg coupling device (LMU) at each time during the ballast process.

[0044] Figure 9 It is a point position diagram of the deck support structure (DSU) and the leg coupling device (LMU). DETAILED DESCRIPTION

[0045] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below, obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0046] Embodiment one:

[0047] A cabin dynamic ballast method for float-over operation model test is applied to a float-over operation barge, as shown in the figure, which comprises a barge empty ship model 1 and a cabin 2, the cabin 2 is arranged on the barge empty ship model 1, in this embodiment, 15 cabins 2 are taken as an example for display, in addition, each cabin 2 is configured with a ballast water pump and a ballast water pump, realizing independent water filling and water discharging control of each cabin 2, and then realizing the continuous load transfer process. Figure 1

[0048] Specifically, as shown in the figure, the method comprises the following steps: Figure 2

[0049] S1: obtaining the finite element model, mass parameter and center of gravity coordinate of the barge empty ship model, obtaining the finite element model, unloaded mass and center of gravity coordinate of the barge cabin model, calculating the initial mass and center of gravity coordinate of the float-over operation barge;

[0050] S2: setting the predetermined ballast parameters of the float-over operation barge;

[0051] S3: setting the barge positive float target optimization function, the maximum target optimization function of the roll inertia moment and the draft target optimization function, and setting the constraint condition;

[0052] S4: calculating the mass of the ballast water of each cabin at each time through the optimization algorithm, and performing ballast control;

[0053] S5: obtaining the increased mass of each cabin in the ballast process, calculating the mass and center of gravity coordinate of the float-over operation barge in the ballast process, and returning to S4.

[0054] The cabin dynamic ballast method for float-over operation model test of the embodiment can be used for complete reproduction of the continuous simulation of the load transfer of the float-over operation process in the water pool model, and then the potential risks of the float-over operation can be accurately captured, which is of great significance to the safety of the float-over operation system.

[0055] The cabin dynamic ballast method for float-over operation model test of the embodiment, at the initial time, determines the ballast scheme through S4, that is, the total mass of the ballast water of each cabin at each time during the ballast, in the ballast process, S5 is executed through real-time feedback data, and returns to S4, and the mass of the ballast water of each cabin at each time is fine-tuned, so as to realize the continuous simulation of the load transfer of the float-over operation, so as to improve the precision and efficiency of the simulation of the float-over operation model test.

[0056] ​​In an optional embodiment, in step S1, the initial mass and center of gravity coordinates of the towing barge are calculated using the following formula:

[0057] ;

[0058] ;

[0059] ;

[0060] ;

[0061] In the formula, The initial mass of the barge used for the tugboat operation. For the quality of the empty barge model, For the first The mass of each compartment when it is not ballasted For the number of cabins, , , These are the initial center of gravity coordinates of the barge during the floating overhaul operation when the compartments are not ballasted. , , These are the coordinates of the center of gravity of the empty barge model. , , The first The center of gravity coordinates of each compartment when it is not ballasted.

[0062] In this embodiment, reference Figure 1 A coordinate system is constructed with the center of the stern of the floating barge when it is stable as the origin, the length direction of the floating barge as the x-axis, the width direction of the floating barge as the y-axis, and the vertical direction as the z-axis, and the coordinate values ​​are calculated in this coordinate system.

[0063] In an optional embodiment, in step S5, the mass and center of gravity coordinates of the ballast process of the floating overhaul barge are calculated using the following formula:

[0064] ;

[0065] ;

[0066] ;

[0067] ;

[0068] In the formula, The mass of the barge used for ballast operations at time t is given. When the ballast is carried out to the tth time Ballast mass of each compartment , , Ballasting to The coordinates of the center of gravity of the barge used for floating overboard operations. , , When the ballast is carried out to the tth time The coordinates of the center of gravity of each compartment.

[0069] In this embodiment, a flow sensor can be installed inside the compartment to monitor the flow rate of the incoming and outgoing water, thereby obtaining the mass increase of the compartment.

[0070] In this embodiment, a time interval can be set, such as 30 seconds or 1 minute; and S5 is executed according to the time interval.

[0071] In an optional embodiment, in S2, the predetermined ballast parameters of the floating barge include: the initial draft of the barge, the draft during the docking process, and the draft during the withdrawal phase.

[0072] In an optional embodiment, in step S3, the target optimization functions for barge buoyancy, maximum roll moment of inertia, and ballast load, as well as the constraints, are as follows:

[0073] m;

[0074] ;

[0075] kg;

[0076] ;

[0077] In the formula, Ballasting to Time The total mass of ballast water in each compartment The mass of the barge used for ballast operations at time t is given. It is the acceleration due to gravity. Ballasting The coordinates of the center of gravity of the barge used for floating overboard operations. For the process After ballast The mass increase of each compartment, where Δt is the time interval. Ballasting The target value for the center of gravity coordinates of the barge used in the floating overlay operation can typically be taken as... , For the barge's rolling moment of inertia, , These are the times when the ballast is carried out (t). The coordinates of the center of gravity of each compartment , , are the length, width and height of the first cabin, is the target mass of the float-over barge when the ballast is carried out to is the density of the ballast water. In an alternative embodiment, in the S4, the second generation non-dominated sorting genetic algorithm is used to solve the multi-objective optimization function to calculate the mass of the ballast water in each cabin.

[0078] In this embodiment, the multi-objective optimization function is solved according to the mass and the center of gravity coordinates of the float-over barge, the target optimization function and the constraint condition to obtain the total mass of the ballast water in each cabin at each time, and then when a certain time is reached, the difference between the actual mass of the water in the cabin at the current time and the total mass of the ballast water calculated is used to control the ballast water pump and / or the ballast water pump to make the mass of the water in the cabin reach the total mass of the ballast water calculated.

[0079] In this embodiment, the multi-objective optimization function is solved according to the mass and the center of gravity coordinates of the float-over barge, the target optimization function and the constraint condition to obtain the total mass of the ballast water in each cabin at each time, and then when a certain time is reached, the difference between the actual mass of the water in the cabin at the current time and the total mass of the ballast water calculated is used to control the ballast water pump and / or the ballast water pump to make the mass of the water in the cabin reach the total mass of the ballast water calculated.

[0080] The effectiveness of the method of this embodiment is verified by combining specific embodiments.

[0081] The ballast setting parameters are set as follows: the initial draft of the barge is 19.625 cm, the draft during the docking process is 23.375 cm, and the draft during the barge withdrawal stage is 24.125 cm. The initial target mass of the barge is 731.8 kg, the initial target mass during the docking process is 917.23 kg, and the initial target mass during the barge withdrawal stage is 1070.05 kg. The target mass between states is obtained according to the initial value by the buoyancy calculation method.

[0082] The second generation non-dominated sorting genetic algorithm is used to obtain the mass change curve of the ballast water in each cabin at each time, as shown in Figure 3 and 4 .

[0083] The vertical coordinate change curve of the center of gravity of the float-over barge and the upper block at each time during the ballast process is obtained (the method for obtaining the vertical coordinate of the center of gravity is the same as that of the prior art), as shown in Figure 5 and 6 . With the progress of the ballast process, the draft of the float-over barge gradually increases, and the center of gravity of the float-over barge and the upper block gradually decreases. When it decreases to a certain extent, the weight of the upper block is completely borne by the foundation structure, and the center of gravity no longer changes. The draft and the vertical center of gravity of the float-over barge continue to increase until the upper block and the float-over barge structure are completely separated.

[0084] ​The stress curves of the deck support unit (DSU) and the leg coupling unit (LMU) at each time of the ballast process are obtained (the method for obtaining the stress values is the same as that in the prior art), as shown in Figure 7 and 8 The point arrangement of the leg coupling unit (LMU) and the deck support unit (SDU) is shown in Figure 9 With the progress of the ballast process, the upper block will continuously collide with the foundation structure and the float-on barge, but due to the continuous transfer of the load, the average value of the collision force between the upper block and the foundation structure will continuously increase, and the average value of the collision force between the upper block and the float-on barge will continuously decrease.

[0085] The above merely describes the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical solutions and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for dynamic ballast loading of compartments for float-over operation model testing, characterized in that, Includes the following steps: S1: Obtain the finite element model, mass parameters, and center of gravity coordinates of the empty barge model; obtain the finite element model, unloaded mass, and center of gravity coordinates of the barge compartment model; calculate the initial mass and center of gravity coordinates of the floating barge. S2: Set the predetermined ballast parameters for the floating overhaul barge; the predetermined ballast parameters for the floating overhaul barge include: the initial draft of the barge, the draft during the docking process, and the draft during the withdrawal phase; S3: Set the target optimization functions for barge buoyancy, maximum moment of inertia, and ballast volume, and set the constraints; The objective optimization functions for barge buoyancy, maximum roll moment of inertia, and ballast load are as follows, along with the constraints: m； ； kg; ； In the formula, Ballasting to Time The total mass of ballast water in each compartment The mass of the barge used for ballast operations at time t is given. It is the acceleration due to gravity. Ballasting The coordinates of the center of gravity of the barge used for floating overboard operations. For the process After ballast The mass increase of each compartment, where Δt is the time interval. Ballasting The target value of the center of gravity coordinates of the barge used in the floating overhaul operation. For the barge's rolling moment of inertia, , These are the times when the ballast is carried out (t). The coordinates of the center of gravity of each compartment , , The first The length, width, and height of each compartment Ballasting The target quality of the floating barge during the operation. The density of ballast water, When the ballast is carried out to the tth time The coordinates of the center of gravity of each compartment When the ballast is carried out to the tth time Ballast mass of each compartment; S4: Calculate the mass of ballast water in each compartment at each time point using an optimization algorithm, and perform ballast control. S5: Obtain the mass increase of each compartment during ballasting, calculate the mass and center of gravity coordinates of the ballasting barge during the floating operation, and return to S4.

2. The method for dynamic ballast loading of a compartment for a floating operation model test according to claim 1, characterized in that, In step S1, the initial mass and center of gravity coordinates of the floating operation barge are calculated using the following formula: ； ； ； ； In the formula, The initial mass of the barge used for the tugboat operation. For the quality of the empty barge model, For the first The mass of each compartment when it is not ballasted For the number of cabins, , , These are the initial center of gravity coordinates of the barge during the floating overhaul operation when the compartments are not ballasted. , , These are the coordinates of the center of gravity of the empty barge model. , , The first The center of gravity coordinates of each compartment when it is not ballasted.

3. The method for dynamic ballast loading of a compartment for a floating operation model test according to claim 2, characterized in that, In step S5, the mass and center of gravity coordinates of the ballast barge during the overloading operation are calculated using the following formula: ； ； ； ； In the formula, The mass of the barge used for ballast operations at time t is given. When the ballast is carried out to the tth time Ballast mass of each compartment , , Ballasting to The coordinates of the center of gravity of the barge used for floating overboard operations. , , When the ballast is carried out to the tth time The coordinates of the center of gravity of each compartment.

4. The method for dynamic ballast loading of a compartment for a floating operation model test according to claim 1, characterized in that, In step S4, a second-generation non-dominated sorting genetic algorithm is used to solve the multi-objective optimization function and calculate the mass of ballast water in each compartment.

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