Floating dock lightering analysis method

Abstract

The invention provides a floating dock lightering analysis method which comprises the steps that finite element models of a ship to be lighted and a bearing beam are established in finite element analysis software, the bearing beam is arranged on a bearing trolley and can move along with the bearing trolley, and a plurality of cushion blocks used for supporting the ship are arranged on the bearing beam; calculating the reaction force of each cushion block, and arranging the reaction force to form a reaction force distribution diagram; judging whether the bearing beam with the deformation degree exceeding the allowable standard exists or not; in the lightering process, a plurality of typical stowage working conditions are selected, overall stress analysis is conducted on the floating dock under the typical stowage working conditions, and a floating dock stowage scheme is determined; a finite element model of the floating dock is established, a plurality of typical stress working conditions are selected in the lightering process, and finite element analysis is conducted on stress distribution and deformation of the floating dock structure under the typical stress working conditions. According to the technical scheme, the calculation efficiency and simulation precision of the floating dock lightering process can be effectively improved, and the safety of the ship during floating dock lightering is better ensured.

Description

Technical Field

[0001] The present application relates to the field of shipbuilding, and in particular to a floating dock transshipment analysis method. Background Art

[0002] With the continuous increase in global trade activities, the volume of cargo transportation between countries has shown a significant growth trend. In order to adapt to the needs of market competition and improve transportation efficiency and economy, large transport ships have emerged, and under the current global freight situation, the order volume of large transport ships has continued to rise. At the same time, the dock resources of shipbuilding companies are usually limited and cannot be easily increased. Therefore, how to ensure that each batch of ships can be launched smoothly according to the established plan under the conditions of limited dock resources in a reasonable way, thereby improving the overall production capacity, has become a key issue that needs to be urgently solved in the shipbuilding industry. After the construction of large ships is completed, floating dock barge launching is usually adopted. Compared with launching methods such as inclined launching and slideway launching, the floating dock barge launching method has higher stability. Specifically, during the ship launching process, the floating dock can provide good support for it, thereby reducing the shaking of the ship and helping to ensure the smooth launching of the ship. In addition, when the floating dock barge launching method is adopted, the surrounding environment is in a controllable state, thereby reducing the impact of various external uncertainties on the ship launching, and also providing a relatively safe operating environment for the staff.

[0003] When using inclined launching and slide launching, the traditional method is usually to analyze the launching process with the help of engineering experience and simplified calculation methods. However, the floating dock barge launching is a quasi-static process and is not suitable for analysis and evaluation using traditional methods. Therefore, a feasible solution is to use finite element static analysis simulation to conduct structural strength assessment and deformation analysis of the floating dock barge launching process. However, although the finite element method has been applied to a certain extent in the fields of ship structure strength assessment, it has not yet been used to conduct risk assessment of the floating dock barge launching process for large ships, so there is a lack of relevant implementation methods. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a floating dock transfer analysis method, which can effectively improve the calculation efficiency and simulation accuracy of the floating dock transfer process and better ensure the safety of ships during floating dock transfer.

[0005] The present application provides a floating dock transshipment analysis method, comprising the following steps:

[0006] S1. In the finite element analysis software, a finite element model of the ship to be transferred and the load-bearing beam is established, wherein the load-bearing beam is fixedly arranged on the load-bearing trolley and can move with the load-bearing trolley, and a plurality of pads for supporting the bottom of the ship to be transferred are fixedly arranged on the upper surface of the load-bearing beam;

[0007] S2. Arrange multiple load-bearing beams and corresponding load-bearing trolleys under the ship to be transferred according to the preset load-bearing trolley arrangement plan, then apply a jacking force to all the load-bearing beams, drive the pads to support the bottom of the ship to be transferred through the load-bearing beams, and then calculate the support reaction force of each pad according to the jacking force data applied by each load-bearing trolley to the corresponding load-bearing beam, and organize them to form a support reaction force distribution diagram;

[0008] S3, check the load-bearing beam according to the support reaction force distribution diagram to determine whether there is a load-bearing beam with a deformation degree exceeding the allowable standard. If not, proceed to step S4; if so, modify the preset load-bearing trolley layout plan, and then repeat steps S2-S3;

[0009] S4, control the load-bearing trolley to drive the ship to be transferred to move inside the floating dock, select several typical loading conditions from the time the ship to be transferred begins to enter the floating dock to the time the ship to be transferred arrives at the designated position in the floating dock, and perform overall force analysis on the floating dock under each typical loading condition according to the support reaction force distribution diagram, so as to determine the loading scheme of the floating dock under each typical loading condition. The floating dock contains multiple ballast tanks, and the loading refers to changing the overall load distribution of the floating dock by filling or draining different ballast tanks of the floating dock;

[0010] S5. In the finite element analysis software, a finite element model of the floating dock is established. In the process of transferring a ship from the outside of the floating dock to a designated position in the floating dock, several typical stress conditions are selected, and finite element analysis is performed on the stress distribution and deformation of the floating dock structure under the typical stress conditions.

[0011] In an implementable solution, in step S1, every two load-bearing trolleys are grouped into one group, a load-bearing beam is fixedly arranged above each group of load-bearing trolleys, and both ends of the load-bearing beam are respectively fixedly arranged on the upper surfaces of the two load-bearing trolleys.

[0012] In one practicable solution, all the pads have the same size and all form complete contact with the exterior of the vessel.

[0013] In an practicable solution, in step S2, a finite element analysis method is used to calculate the support reaction force of each pad, wherein the support reaction force of the pad is applied to the surface of the load-bearing beam in the form of concentrated force.

[0014] In an implementable scheme, in step S2, the pressure applied by each load-bearing trolley on the ground is calculated based on the lifting force data applied by each load-bearing trolley on the corresponding load-bearing beam, and the pressure is organized into a ground pressure distribution map; in the ground pressure distribution map, the pressure of each load-bearing trolley is applied to the ground in the form of concentrated force.

[0015] In an practicable solution, step S3 includes the following specific steps:

[0016] S31. Evaluate and rank the magnitude of the support reaction force borne by each load-bearing beam through the support reaction force distribution diagram;

[0017] S32, selecting the bearing beam that bears the largest support reaction force from among all the bearing beams as the bearing beam to be checked;

[0018] S33, perform strength check on the load-bearing beam to be checked, and determine whether the deformation degree of the load-bearing beam to be checked exceeds the allowable standard. If it does not exceed the allowable standard, proceed to step S4; if it exceeds the allowable standard, modify the preset load-bearing trolley layout plan, and then repeat steps S2-S3.

[0019] In an implementable solution, in step S4, while selecting a typical loading condition, the seawater tide level prediction data for the actual transshipment time period is also obtained, and then the seawater tide level prediction data is combined with the support reaction force distribution diagram to perform an overall force analysis of the floating dock under the typical loading condition.

[0020] In an implementable solution, in step S4, combined with the ground pressure distribution diagram, in the process from the time the ship to be transferred enters the floating dock to the time the ship to be transferred arrives at the designated position in the floating dock, each time a first preset pressure value enters the floating dock, the current operating condition is defined as a typical loading condition.

[0021] In an practicable solution, in step S4, the floating dock loading solution should ensure that under various typical loading conditions, the lateral inclination of the floating dock is less than 0.25% of the width of the floating dock, and the longitudinal inclination of the floating dock is less than 0.5% of the length of the floating dock.

[0022] In an implementable solution, in step S5, combined with the ground pressure distribution diagram, in the process from the time the ship to be transferred enters the floating dock to the time the ship to be transferred arrives at the designated position in the floating dock, each time a second preset pressure value enters the floating dock, the current operating condition is defined as a typical stress operating condition.

[0023] Compared with the prior art, the beneficial effects of this application include at least:

[0024] The present application provides a floating dock transshipment analysis method, which analyzes the ship support link, the floating dock loading link and the floating dock deformation link respectively, and can quickly and accurately simulate various stress conditions in the entire transshipment process, and compare and analyze various data with the permissible standards, so as to determine whether the entire transshipment process is safe and reliable. When the traditional method is used to analyze the entire transshipment process, a simplified calculation method is usually used. This method is usually time-consuming and labor-intensive, and many detailed factors cannot be taken into account, thereby affecting the precision and accuracy of the calculation. For example, when the traditional method is used to load the floating dock, the actual pressure on each ballast tank of the floating dock is first manually calculated based on the different drafts listed in the floating dock loading manual, and then the pressure is applied to each ballast tank separately in the form of concentrated MPC+mass point. If more dangerous conditions occur during the pressure calculation process, the workload will be greatly increased, making the entire analysis process uncontrollable. In comparison, the technical solution of the present application has greatly improved in terms of computational efficiency, simulation accuracy, etc. The entire transfer process is always under control, and its calculation results can better ensure the safety of ships during floating dock transfer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a flow chart of a floating dock transshipment analysis method according to an embodiment of the present application;

[0027] Figure 2 is the support reaction force distribution diagram;

[0028] Figure 3 is the load diagram of the load-bearing beam;

[0029] Figure 4 This is the first type of ground pressure distribution map;

[0030] Figure 5 This is the second ground pressure distribution map;

[0031] Figure 6 This is a schematic diagram of the finite element analysis of the floating dock ballast tank;

[0032] In the figure: 1, vessel to be transferred; 2, floating dock; 3, load-bearing beam; 4, pad; L1, first direction. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0035] like Figure 1 As shown, the present application provides a floating dock transshipment analysis method, which is characterized by comprising the following steps:

[0036] S1. In the finite element analysis software, a finite element model of the ship to be transferred and the load-bearing beam is established, wherein the load-bearing beam is fixedly arranged on a load-bearing trolley and can move with the load-bearing trolley, and a plurality of pads for supporting the bottom of the ship to be transferred are fixedly arranged on the upper surface of the load-bearing beam.

[0037] S2. Arrange multiple load-bearing beams and corresponding load-bearing trolleys under the ship to be transferred according to the preset load-bearing trolley arrangement plan, then apply lifting force to all load-bearing beams, drive the pads to support the bottom of the ship to be transferred through the load-bearing beams, and then calculate the support reaction force of each pad according to the lifting force data applied by each load-bearing trolley to the corresponding load-bearing beam, and organize it to form a support reaction force distribution diagram, as shown in the following figure. Figure 2 shown.

[0038] S3. Check the load-bearing beam according to the support reaction force distribution diagram to determine whether there is a load-bearing beam with a deformation degree exceeding the allowable standard. If not, proceed to step S4; if so, modify the preset load-bearing trolley layout plan, and then repeat steps S2-S3.

[0039] S4, control the load-bearing trolley to drive the ship to be transferred to move inside the floating dock, select several typical loading conditions from the time the ship to be transferred enters the floating dock to the time the ship to be transferred arrives at the designated position in the floating dock, and perform overall force analysis on the floating dock under each typical loading condition according to the support reaction force distribution diagram, so as to determine the loading scheme of the floating dock under each typical loading condition. The floating dock contains multiple ballast tanks, and the loading refers to changing the overall load distribution of the floating dock by filling or draining different ballast tanks of the floating dock.

[0040] S5. In the finite element analysis software, a finite element model of the floating dock is established. In the process of transferring a ship from the outside of the floating dock to a designated position in the floating dock, several typical stress conditions are selected, and finite element analysis is performed on the stress distribution and deformation of the floating dock structure under the typical stress conditions.

[0041] The technical solution of the present application analyzes the ship support link, the floating dock loading link and the floating dock deformation link respectively, and can quickly and accurately simulate various stress conditions in the entire transshipment process, and compare and analyze various data with the permissible standards, so as to determine whether the entire transshipment process is safe and reliable. When the traditional method is used to analyze the entire transshipment process, a simplified calculation method is usually adopted. This method is usually time-consuming and labor-intensive, and many detailed factors cannot be taken into account, thereby affecting the precision and accuracy of the calculation. For example, when the traditional method is used to load the floating dock, the actual pressure on each ballast tank of the floating dock is first manually calculated according to the different drafts listed in the floating dock loading manual, and then the pressure is applied to each ballast tank in the form of concentrated MPC+mass point. If more dangerous working conditions occur during the pressure calculation process, the workload will be greatly increased, making the entire analysis process uncontrollable. In contrast, the technical solution of the present application has greatly improved in terms of calculation efficiency, simulation accuracy, etc., and the entire transshipment process is always in a controllable state, and its calculation results can better ensure the safety of ships during transshipment at the floating dock.

[0042] In one embodiment, in step S1, every two load-bearing trolleys can be grouped into one group, and a load-bearing beam is fixedly arranged above each group of load-bearing trolleys, wherein the two ends of the load-bearing beam are respectively fixedly arranged on the upper surfaces of the two load-bearing trolleys. Preferably, two or three evenly spaced pads can be arranged on each load-bearing beam, and the specific number and arrangement of the pads can be changed as needed, and no excessive restrictions are made here. In addition, the pads can be made of wood materials, composite materials or concrete materials, and there is no specific restriction.

[0043] In one embodiment, in step S2, the finite element analysis method can be used to calculate the support reaction force of each pad, wherein the support reaction force of the pad is applied to the surface of the load-bearing beam in the form of concentrated force. Preferably, all pads can be set to have the same size and form complete contact with the outside of the ship. Specifically, it can be set that in the initial state, the ship structure and the load-bearing beam have no plastic deformation, and then the pad is simulated by the Spring unit, and the stiffness of the Spring unit can be the stiffness of the actual pad material. When the calculation is completed, the force value of the Spring unit is read, and the force value is the actual support reaction force of the pad. Then, the actual support reaction force of the pad can be applied to the load-bearing beam in the form of concentrated force, and the force and deformation of the load-bearing beam are analyzed.

[0044] In one embodiment, step S3 may include the following specific steps:

[0045] S31. Evaluate and rank the magnitude of the support reaction force borne by each load-bearing beam through the support reaction force distribution diagram;

[0046] S32, selecting the bearing beam that bears the largest support reaction force from among all the bearing beams as the bearing beam to be checked;

[0047] S33, perform strength check on the load-bearing beam to be checked, and determine whether the deformation degree of the load-bearing beam to be checked exceeds the allowable standard. If it does not exceed the allowable standard, proceed to step S4; if it exceeds the allowable standard, modify the preset load-bearing trolley layout plan, and then repeat steps S2-S3.

[0048] For example, Figure 2 As shown in the figure, according to the support reaction force distribution diagram, the load-bearing beam with the largest support reaction force is selected from all the load-bearing beams for strength verification. Then the specific values ​​of the three support reaction forces are applied to the load-bearing beams in the form of concentrated forces, as shown in Figure 3 As shown in the figure, after finite element calculation, the final cushion support reaction force does not exceed the allowable standard, and the absolute deformation of the bearing beam is small, which means that the current load-bearing trolley arrangement scheme can meet the needs of the ship transfer process. If the cushion support reaction force exceeds the allowable standard, you can add a load-bearing trolley, a bearing beam and a cushion at the position where the cushion support reaction force exceeds the standard, and determine the load-bearing trolley arrangement scheme that can make the cushion support reaction force meet the allowable standard through multiple iterative calculations.

[0049] In addition, if Figure 4 and Figure 5 As shown, in step S2, the pressure applied by each load-bearing trolley on the ground can also be calculated based on the lifting force data applied by each load-bearing trolley on the corresponding load-bearing beam, and a ground pressure distribution diagram can be formed, in which the pressure of each load-bearing trolley is applied to the ground in the form of concentrated force.

[0050] In one embodiment, in step S4, while selecting a typical loading condition, the seawater tide level prediction data for the actual transshipment period is also obtained, and then the seawater tide level prediction data is combined with the support reaction force distribution diagram to perform an overall force analysis on the floating dock under the typical loading condition. This is because, in the actual transshipment process, in addition to the parameters of the ship to be transshipped and the floating dock itself, the seawater tide level is also an influencing factor that cannot be ignored. Since the floating dock is completely floating in the seawater, the seawater tide level will interfere with the longitudinal and transverse balance of the floating dock, which may cause the longitudinal and transverse tilt of the floating dock to exceed the allowable standard.

[0051] Since the speed of the ship entering the floating dock is relatively slow during the actual transfer, the whole process takes a long time, for example, it may take 5-10 hours, and it is difficult to dynamically analyze the process of the entire ship entering the floating dock. Therefore, the technical solution of the present application selects some typical loading conditions for static analysis. In step S4, in combination with the ground pressure distribution diagram, in the process from the ship to be transferred entering the floating dock to the ship to be transferred arriving at the designated position in the floating dock, whenever a first preset pressure value enters the floating dock, the current working condition is defined as a typical loading condition. Among them, the first preset pressure value can be set to 5% of the total pressure of all the carrying trolleys on the ground, that is, a total of 20 typical loading conditions are selected. In addition, for simplicity, it can also be selected to define the current working condition as a typical loading condition whenever a certain ship length (for example, 5% of the total length of the ship) enters the floating dock. The specific typical loading condition selection method can be determined according to the situation, and there is no excessive restriction here.

[0052] When loading a floating dock, the principle of keeping the vertical center of the ship as close to the center of gravity of the floating dock as possible should be followed, so that the longitudinal and lateral inclinations of the floating dock do not exceed the allowable standards during the transfer process, and the floating dock does not appear in a sagging condition, ensuring that the structural stress of the floating dock does not increase due to inclination, thereby avoiding large deformation of the floating dock due to uneven force.

[0053] In one embodiment, in step S4, the loading scheme of the floating dock under each typical loading condition can ensure that the lateral tilt amplitude of the floating dock is less than 0.25% of the width of the floating dock, and the longitudinal tilt amplitude of the floating dock is less than 0.5% of the length of the floating dock by adjusting the water injection amount or the water displacement amount of each ballast tank of the floating dock. In addition, according to the specific size of the ship and the floating dock and the requirements of the launching area, the lateral tilt amplitude and the longitudinal tilt amplitude requirements of the floating dock can also be appropriately adjusted, for example, the lateral tilt amplitude and the longitudinal tilt amplitude of the floating dock can be set to be less than 0.2% and 0.4% respectively.

[0054] In one embodiment, in step S5, a finite element model of a floating dock can be established in a finite element analysis software by simulating plate and shell elements in combination with the design drawing of the floating dock. In the process of creating a finite element model of a floating dock, the spatial distribution of its internal ballast tanks and the opening positions of each compartment should be confirmed in combination with the design drawing of the floating dock to ensure the accuracy of the internal compartments of the finite element model of the floating dock and to ensure that the boundaries of each compartment are consistent with the actual structure, so that the ballast water load for achieving longitudinal and transverse balance of the floating dock can be applied in subsequent steps. The weight of the finite element model can be adjusted according to the rib position of the floating dock based on the actual empty ship weight distribution of the floating dock to ensure that the weight distribution of the finite element model is consistent with the actual weight distribution. Specifically, the deviation between the center of gravity position of the finite element model and the actual center of gravity position can be made not to exceed 1% of the length of the floating dock. The finite element model weight adjustment methods that can be used include but are not limited to: directly assigning different density values ​​to the material of the floating dock in the finite element software, thereby adjusting the weight distribution of the floating dock; adjusting the weight difference between the model and the actual structure by adjusting the mass points, where the mass points refer to the concentrated mass loads applied to certain nodes on each rib position in the floating dock model.

[0055] Similarly, since the speed of a ship entering a floating dock is relatively slow during actual transshipment, it is difficult to dynamically analyze the entire process of the ship entering the floating dock. Therefore, the technical solution of this application selects some typical stress conditions for static analysis. Figure 4 As shown, in the process that the carrying trolley drives the ship to be transferred 1 to enter the floating dock 2 along the first direction L1, the bending moment curve profile borne by the floating dock will change accordingly, so when selecting the typical stress condition, the bending moment peak value can be as large as possible and the bending moment curve profile difference can be as obvious as possible. Specifically, in step S5, in combination with the ground pressure distribution diagram, in the process from the ship to be transferred entering the floating dock to the ship to be transferred arriving at the designated position in the floating dock, whenever a second preset pressure value enters the floating dock, the current working condition is defined as a typical stress working condition. Among them, the second preset pressure value can be set to 5% of the total pressure of all the carrying trolleys on the ground, that is, a total of 20 typical stress working conditions are selected. In addition, for simplicity, it can also be selected to define the current working condition as a typical stress working condition whenever a certain ship length (for example, 5% of the total length of the ship) enters the floating dock. The specific typical stress working condition selection method can be determined according to the situation, and no excessive restrictions are made here.

[0056] When conducting finite element analysis on typical stress conditions, loads and boundary conditions are first applied to the floating dock model, including but not limited to the pressure of the loading trolley on the floating dock during ship transfer, the gravity of the floating dock itself, the water gravity of the floating dock ballast tank, and the hydrostatic pressure of the hull and other internal compartments. Specifically, Figure 4 and Figure 5As shown, according to the ground pressure distribution diagram, the ground pressure distribution of all the carrying trolleys on the floating dock at any time point in the transfer process can be easily obtained. By establishing the weight condition, the floating dock's own gravity can be automatically generated and applied to the floating dock finite element model. Under different typical stress conditions, due to the different drafts of the floating dock, the static pressure of the ballast water and other internal compartments in the floating dock and the hydrostatic pressure of the outer shell will change accordingly. In order to improve the calculation efficiency and ensure the calculation accuracy, the technical solution of the present invention does not adopt the traditional method of constraining MPC+mass points, but defines the corresponding local coordinate system for each ballast tank, and then quickly applies hydrostatic pressure to multiple ballast tanks by modifying the draft value of the floating dock, without manually calculating the water pressure. Specifically, the water pressure formula P=ρgh can be compiled into the finite element software, where ρ is the seawater density in the sea area where the transfer process is actually carried out, g is the acceleration of gravity, and the h value is the actual draft value of each ballast tank. In the finite element software, the hydrostatic pressure load is added through the water pressure formula. For each ballast tank, the analysis coordinates of the hydrostatic pressure load are selected from the local coordinates of the corresponding ballast tank itself. Figure 6 As shown in the figure, the actual draft height of a ballast tank of the floating dock is 4.2m. Therefore, a local coordinate system with coordinate values ​​of (0, 0, 4200) is defined for the ballast tank, and the hydrostatic pressure load is applied using the water pressure formula. Then, the local coordinate system is selected as the analysis coordinate. The finite element software will automatically and accurately apply hydrostatic pressure to all units in the target ballast tank according to the height. There is no need for manual calculation throughout the process, which greatly improves work efficiency. For the static pressure of other internal compartments of the floating dock, it can also be applied in the same way as the above-mentioned method of applying hydrostatic pressure load. It should be noted that due to the longitudinal inclination of the floating dock during the transshipment process, when applying the hydrostatic pressure load on the hull to the floating dock, the draft depth of the bow and stern of the floating dock should be comprehensively considered. Therefore, the corresponding local coordinate systems need to be defined for the bow and stern of the floating dock.

[0057] After applying various loads to the floating dock in the above manner, the loads can be integrated to obtain the shear force and bending moment results, and the results can be compared with the actual shear force and bending moment listed in the floating dock loading manual. If the calculated results and the manual values ​​can form a good fit, it means that the calculated results are true and reliable. In the technical solution of the present invention, due to the method of defining a local coordinate system, the error between the load applied in the finite element software and the actual load can be controlled within 1%, thereby improving the accuracy and efficiency of the calculation. Finally, the deformation and stress calculation results of the floating dock can be obtained, and the calculated results can be compared with the allowable standards listed in the floating dock loading manual to determine whether the entire transshipment process can be completed safely and smoothly, thereby completing the evaluation of the floating dock transshipment plan.

[0058] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. 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 floating dock transshipment analysis method, characterized in that: include: S1. In the finite element analysis software, a finite element model of the ship to be transferred and the load-bearing beam is established, wherein the load-bearing beam is fixedly arranged on the load-bearing trolley and can move with the load-bearing trolley, and a plurality of pads for supporting the bottom of the ship to be transferred are fixedly arranged on the upper surface of the load-bearing beam; S2. Arrange multiple load-bearing beams and corresponding load-bearing trolleys under the ship to be transferred according to the preset load-bearing trolley arrangement plan, then apply a jacking force to all the load-bearing beams, drive the pads to support the bottom of the ship to be transferred through the load-bearing beams, and then calculate the support reaction force of each pad according to the jacking force data applied by each load-bearing trolley to the corresponding load-bearing beam, and organize them to form a support reaction force distribution diagram; S3, check the load-bearing beam according to the support reaction force distribution diagram to determine whether there is a load-bearing beam with a deformation degree exceeding the allowable standard. If not, proceed to step S4; if so, modify the preset load-bearing trolley layout plan, and then repeat steps S2-S3; S4, controlling the load-bearing trolley to drive the ship to be transferred to move into the floating dock, selecting several typical loading conditions from the time when the ship to be transferred begins to enter the floating dock to the time when the ship to be transferred arrives at the designated position in the floating dock, and performing an overall force analysis on the floating dock under each typical loading condition according to the support reaction force distribution diagram, so as to determine the loading scheme of the floating dock under each typical loading condition; the floating dock includes a plurality of ballast tanks, and the loading refers to changing the overall load distribution of the floating dock by filling or draining different ballast tanks of the floating dock; S5. In the finite element analysis software, a finite element model of the floating dock is established. In the process of transferring a ship from the outside of the floating dock to a designated position in the floating dock, several typical stress conditions are selected, and finite element analysis is performed on the stress distribution and deformation of the floating dock structure under the typical stress conditions.

2. The floating dock transshipment analysis method according to claim 1, characterized in that: In step S1, every two load-bearing trolleys are grouped into one group, a load-bearing beam is fixedly arranged above each group of load-bearing trolleys, and two ends of the load-bearing beam are respectively fixedly arranged on the upper surfaces of the two load-bearing trolleys.

3. The floating dock transshipment analysis method according to claim 1, characterized in that: All pads are of the same size and all make full contact with the exterior of the vessel.

4. The floating dock transshipment analysis method according to claim 1, characterized in that: In step S2, the support reaction force of each pad is calculated by using a finite element analysis method, wherein the support reaction force of the pad is applied to the surface of the load-bearing beam in the form of concentrated force.

5. The floating dock transshipment analysis method according to claim 1, characterized in that: In step S2, the pressure exerted by each load-bearing trolley on the ground is calculated according to the lifting force data exerted by each load-bearing trolley on the corresponding load-bearing beam, and the pressure distribution diagram of the ground is formed; In the ground pressure distribution diagram, the pressure of each load-bearing trolley is applied to the ground in the form of concentrated force.

6. The floating dock transshipment analysis method according to claim 1, characterized in that: Step S3 includes: S31. Evaluate and rank the magnitude of the support reaction force borne by each load-bearing beam through the support reaction force distribution diagram; S32, selecting the bearing beam that bears the largest support reaction force from among all the bearing beams as the bearing beam to be checked; S33, perform strength check on the load-bearing beam to be checked, and determine whether the deformation degree of the load-bearing beam to be checked exceeds the allowable standard. If it does not exceed the allowable standard, proceed to step S4; if it exceeds the allowable standard, modify the preset load-bearing trolley layout plan, and then repeat steps S2-S3.

7. The floating dock transshipment analysis method according to claim 1, characterized in that: In step S4, while selecting the typical loading condition, the seawater tide level prediction data for the actual transshipment period is also obtained, and then the seawater tide level prediction data is combined with the support reaction force distribution diagram to perform an overall force analysis on the floating dock under the typical loading condition.

8. The floating dock transshipment analysis method according to claim 5, characterized in that: In step S4, combined with the ground pressure distribution diagram, in the process from the time when the ship to be transferred enters the floating dock to the time when the ship to be transferred arrives at the designated position in the floating dock, whenever a first preset pressure value enters the floating dock, the current working condition is defined as a typical loading working condition.

9. The floating dock transshipment analysis method according to claim 1, characterized in that: In step S4, the floating dock loading plan should ensure that under each typical loading condition, the lateral inclination of the floating dock is less than 0.25% of the width of the floating dock, and the longitudinal inclination of the floating dock is less than 0.5% of the length of the floating dock.

10. The floating dock transshipment analysis method according to claim 1, characterized in that: In step S5, combined with the ground pressure distribution diagram, in the process from the time when the ship to be transferred enters the floating dock to the time when the ship to be transferred arrives at the designated position in the floating dock, each time a second preset pressure value enters the floating dock, the current working condition is defined as a typical stress working condition.

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