KR101045045B1 - Turret mooring system for model testing of floating offshore structures - Google Patents

Abstract

PURPOSE: A model testing apparatus for a floating offshore structure is provided to simply prevent the penetration of water into a vessel model using a waterproof film. CONSTITUTION: A loading part(10) is formed into a box shape structure, and both ends of the loading part are combined with the floor of a vessel model. The height of the loading part is adjusted. 6-axis load cell(20) is mounted at the internal ceiling of the loading part. A turret rotary axis(30) is combined with the lower side of the 6-axis load cell while rotation. A plurality of 1-axis load cell(40) is in connection with the lower end part of the turret rotary axis.

Description

Turret Mooring System for Model Testing of Floating Offshore Structures}

The present invention relates to a model test apparatus for effectively measuring the tension applied to the mooring line (Mooring Line) in the model test of the floating marine structure and thereby the force (force) acting on the model test ship.

1. Offshore Structure (Figure 1)

An offshore structure is a structure that can remain at a point in the sea under any weather conditions without any structure connected to the land.

Marine structures are used in various ways. It is installed for the development and production of subsea oil fields and gas, and is also used as a port structure for berthing large tankers. This is because large tankers need to be deep enough to berth, so when dredging is not possible, the jetty and dolphin must be extended deep into the harbor. This is known as Offshore Marine Terminal. In recent years, offshore structures are being built for power plants, oil storage facilities, and fishery relay stations.

Looking at the materials used for the construction of offshore structures, the most commonly used material is steel. At this time, the part that goes under the sea uses a steel pipe with a circular cross section, because the cross-sectional shape receives less force from waves or currents. Another reason is that the steel pipe pile can be used as a foundation, and buoyancy can be used when installing the structure. You can receive it.

The upper structure of the sea is made of steel such as H-beam, which is easy to manufacture and easy to maintain. Steel has been widely used as a material for offshore structures due to its advantages such as ease of manufacture and installation, clarity of design, and robustness of structure, despite the disadvantages of corrosion and sticking marine life.

In structures with deep water depths and hard seabed geology, concrete structures are often used. Concrete is highly corrosion resistant and can maintain a stable state with its own weight. The huge cylindrical concrete can be used as a storage facility for oil, etc., and can be easily transported, installed, and inspected. However, it is difficult to manufacture and limited seabed geological conditions, such as its use is limited to the North Sea or polar regions.

The marine structures can be divided into three categories as follows.

(1) floating structure

It has been mainly used for oil drilling, but recently, its use has been spread to offshore power plants and oil storage facilities.

Floating structures for oil drilling have the proposition that mobility and fixedness must be ensured at the same time. In other words, if the drilling fails, it should be able to move to another area immediately, and during drilling, it should be secured so as not to exert excessive force on the drilling pipe. There are three common uses for floating rigs:

① Drill Ship (Fig. 2)

Magnetic propulsion is possible, but there is maneuverability, but fixedness is secured by mooring (Mooring) or dynamic positioning system (Dynamic Positioning), etc. In bad weather, rolling, pitching, etc. occurs, making operation difficult.

② Jack-Up Rig (FIG. 3)

During operation, three legs are fixed to the sea floor to ensure stability. After the drilling, the jack is lifted up by the jack-up method and floated by the buoyancy of the hull. At this time, the towing ship is towing to move to another area. The fixedness is superior to the drill ship, but it is impossible to operate in deep water, it is weak in maneuverability, and the jack up work may be suspended in bad weather.

③ Semi submersible drilling ship (Semisubmersible) (FIG. 4)

It is a floating structure with four or six legs and horizontal members called pontoons that connect each leg create buoyancy. It can be said to be stable in structure, but the upper deck area is large, and thus, a large amount of equipment can be shipped, which may result in temporary instability in bad weather. This has actually caused a major rollover. It is weak in mobility because it cannot propel itself, and it takes a lot of production and operating costs.

④ Floating Production Storage Offloading (FPSO) (FIG. 5)

As a floating oil production and storage facility, it is a special ship suitable for small-scale deep sea oilfield development because it is possible to store and unload crude oil from the sea, and to move freely.

In the high oil price era, oil producers around the world are investing heavily in oil exploration development projects, presuming further increases in crude oil prices. As a result, the economic and convenient movement of offshore oil field development has led to the emergence of a new type of FPSO unlike the existing fixed oil rigs.

The overall look of the FPSO looks like a regular super tanker. However, at the upper part, facilities for crude oil refining, gas compression, crude oil unloading, seawater injection, and self-power generation are installed.

Recently, nuclear power plants, gas turbine plants, waste incinerators, etc., which are increasingly difficult to select due to environmental pollution and NIMBY phenomenon, are being built on floating structures, and can be taken off and landed on large steel structures for 24 hours. Maritime airports, however, remain a long-term challenge. Many small and medium-sized diesel power plants installed on barges are currently installed and operated around the world, and desalination plants, oil and gas storage facilities are also installed as offshore flotation facilities.

(2) fixed structure

Currently, the most commonly used marine stationary structure is a so-called jacket (steel jacket) welding structure (Fig. 6). This structure is usually manufactured on land, then carried on a barge, transported to the area and then launched and launched. At this time, piles are piled through 4 to 8 legs, and the upper main facilities are mainly supported by these piles, and the steel pipe structure supports the piles to the side with legs and braces, so the pile behavior of the lateral force is aggregated. To be done.

The name jacket is given because the structure wraps around the file. The pile is embedded up to about 100 meters below sea level, permanently anchoring the offshore platform to the sea bed and transmitting lateral and vertical loads to the sea floor to keep the structure stable.

The upper main facility consists of a structure with two or three decks, and in a marine complex with multiple platforms, bridges are connected to each platform. The jacket platform typically has a design life of about 20 years and is widely used for offshore oil production, drilling and offshore residential use.

Another type of fixed structure, the concrete gravity structure (GBS) is a structure having a bearing capacity of its own weight, not the pile against the external load (Fig. 7). In order to prevent long-term settlement of the gravity structure, a stable and firm sea floor is needed.

In the polar regions, monotower concrete platforms with large bases are often installed to reduce the risk of collisions with icebergs, and for more economical design in deep seas with hard seabeds. In Cheonhae, the land is built by reclaiming offshore islands to create high resolution cities, offshore airports and oil production facilities.

(3) floating structure

It is a type of floating structure that is connected to steel wires from a fixed structure installed on the sea floor to induce lateral stability of the floating structure. This is the result of efforts to install economic structures in the deep sea. These include guided towers and tension leg platforms.

The guide tower is supported by a steel structure that vertically lowers the platform's vertical load to the sea floor without inclination, and the side loads are inclined in all directions to the steel structure and supported by a steel wire fixed to the sea bottom.

TLP (TLP) is a structure that connects steel wires (Tendon or Tether) vertically from the legs of each corner to the bottom fixed structure, and holds the side loads within a certain limit. The buoyancy of the upper platform always keeps the tension of the wires constant, which attenuates the up and down movement of the platform, providing favorable stability for deep-water well development. TLP is economical in the development of oil wells with low oil reserves, as they can be relocated to another area after work in one area. TLP originally began to be made of steel, but is gradually being designed to be used as a temporary oil storage facility by making top and bottom structures from concrete structures.

In addition, the deep subsea structure is made by connecting the upper part to the jacket-type steel structure and the lower part to the concrete caisson, or conversely the upper part to the concrete floating structure and the lower part to the steel structure truss and connecting it with a special joint to remove the bending force. Articulated Towers are also proposed.

2. Natural conditions to consider when designing offshore structures

(1) depth and seabed

Depth is the vertical distance from the tidal datum to the bottom of the sea. Here, the basic level plane means the lowest low tide plane, and there are very few examples of the water falling below this level. Accurate measurement of depth and a good understanding of the irregularities of the local seabed topography are the starting point for the design of offshore structures, from which it is possible to determine the height of the offshore structure, the substructure of the structure, the vertical positioning of the ship's berth, and the design of corrosion protection. It can also verify the topographic stability of the structure. For continuous measurement of depth, acoustic echo sounder, Precision Depth Recorder and two-dimensional side scan sonar are used.

(2) subsea geology

Physical and engineering grasp of seabed geology supporting the foundation of offshore structures is essential for economic and safe structure design. Subsea geological surveys are conducted to analyze the lipid status of the seabed surface and the seabed strata to the underlying bedrock. Subsea geological surveys usually involve direct boring to obtain continuous lipid samples, which are then investigated and analyzed in the laboratory to collect design data.

However, as a preliminary step in boring, subsurface geological information such as subbottom profiler, boomer, sparker, and air gun should be collected. In this case, sampling of the piston drill, Grab Sampler, etc. may be performed simultaneously for a more practical understanding of the shallow strata. This is because it is necessary to identify the subsea geological characteristics of the surrounding sea area where the structure will be installed to determine the main boring point and to check the geological condition of other non-boring areas. If faults, unusual structures in sediments, abrupt changes in seabed strata, abnormal erosion, and sediment flows are found in the waters around the structure, significant problems may arise.

After analyzing the data of geophysical exploration, the degree of change in the area around the area is considered, and the drilling point and the number of drillings in the seabed are determined by considering the shape, importance, and number of marine structures. The drilled samples are provided with basic data for basic design by identifying various soil characteristics, stress coefficient and displacement of pile through field and laboratory analysis. In particular, it is necessary to analyze the strata close to the seabed surface because the soil here has a great influence on the calculation of the settlement, allowable bearing capacity and horizontal displacement.

(3) sea breeze

Wind affects or causes vibrations and pressures on upper structures and facilities above sea level. The strength of the wind is negligible compared to that of waves or currents, but it is by no means negligible because of the large moment arms from the bottom of the seabed.

Sea level winds can be divided into gusts and continuous winds. A gust is a wind of less than 1 minute and a continuity of wind speed, and a continuous wind of more than 1 minute. Design wind speeds are used for offshore structures and foundations. Wind speeds are applied to the design of individual objects and small wind-sensitive structures.

In deep water guide towers or tension leg platforms with long natural periods, the wind effect spectrum should be used to account for the dynamic effects of the natural periods.

(4) waves

The biggest influence in the design of offshore structures is sea waves. The sea waves apply the most direct force to the foundation design or to the design of each member of the structure, acting as a decisive factor in the size and length design of the members.

The most important characteristic of a wave is its irregularity. Therefore, the spectral model becomes a barometer indicating some sea state, and the structural analysis must also be performed statistically. However, in view of the convenience of design and experience, regular wave modeling is considered to be very suitable for the design of offshore structures. A regular wave is defined as a series of waveforms having a constant wavelength, wave height, and period. The current wave models include airy waves, stokes fifth order waves, and stream function waves. Etc.

Which wave model is applied to the design depends on depth, structure geometry and applied crest. The selected wave is called a design wave. The design wave variables are roughly classified into three types: wave height, wave period, and depth. From this design wave, the final wave force is calculated from the Morrison equation by calculating the velocity and acceleration of the water particles acting on each point of each member or structure.

There are many causes of wave generation, but the biggest one is the effect of wind. Therefore, the maximum design external force is obtained by applying wind and wave in the same direction when designing a structure. In addition, when there are sea wave data for a long time in the area of offshore structure installation, it is not difficult to find the design wave, but sometimes there are only wind speed data, and many methods have been developed to calculate the design wave from this wind speed. In this case, statistically, the significant crest and average crest periods considering the repetition period are calculated, and then the maximum crest (design crest) and corresponding wave periods are calculated from the statistical method.

(5) current

If the wave is the flow of the wave caused by the vibration of the water particles, the current flow can be said that the water particles move directly in the horizontal direction by a number of factors. Thus, when the stream meets the structure, it exerts a constant horizontal force, and even when the ship approaches for berthing, the currents have a constant effect on the ship.

The causes of currents can be divided into large and local ones. Large-scale factors include wind and earth rotation, temperature differences and salinity differences, and local factors include seabed sediment, waves, tides, wind and typhoons. . The velocity of water particles by currents is combined with the velocity of water particles by sea waves to form a total force acting on the structure.

(6) tides

The most noticeable effect of celestial motion on the earth is tides. The high tide that occurs when the moon and the sun attract together, and vice versa, is a familiar oceanic movement that everyone knows from experience. However, the rise and fall of the water surface is not only caused by the celestial body, but the phenomenon caused by the difference in wind, waves, and pressure can not be ignored. Therefore, all of this adds up to determine the maximum design depth.

If the structure is located close to the beach or located in an enclosed inland sea area such as a bay, the lifting effect of the tides, etc. will be remarkable, and if designed without proper consideration, it can have serious consequences. In general, external forces are to be estimated and deck heights are assumed assuming the maximum depth approaching the structure at maximum depth. In addition, the vertical and vertical ranges of the maximum and minimum depths are to be calculated and applied accordingly to the installation of facilities for anchoring, the calculation of the maximum corrosion range for steel structures, and the calculation of the thickness of adherent marine organisms.

(7) Subsea Earthquake

Seismic design is essential for the design of offshore structures. If the offshore structure is a dynamically sensitive structure, it must be accompanied by a dynamic analysis by earthquake. When the structure is of high importance or in the case of very large structures, the lower geological structure should be closely examined to consider faults and sediment movements that may occur simultaneously during an earthquake.

(8) marine life

Over time, marine structures will stick to and grow in marine structures. As the thickness of these marine creatures increases by two to three centimeters, the projected area and volume of each member of the structure under the force of waves or currents increase rapidly. In addition, by roughening the outer surface of each member to increase the drag effect (Drag Effect), in the case of steel also promotes the corrosion phenomenon locally. Therefore, this effect must be considered in the design. On the other hand, as the adherent marine organisms cover the surface of the structure, it may be difficult to maintain and manage the marine structure, which may necessitate partial removal.

(9) other

In addition, the density and salinity of seawater related to the corrosion and seawater properties of marine steel structures, the rapid change according to the depth of seawater temperature, and the hydrostatic pressure that increases by 1 atmosphere at 10 meters are the natural conditions to be considered in the design. In addition, the instability of the seabed caused by sea waves, submarine earthquakes, and rapid sedimentation, and scouring and deposition, which can occur around the foundations of marine structures due to continuous ocean currents and sea waves, must be considered when designing the foundation. Here are the things to go.

3. Mooring method of offshore structures

There are three mooring methods for offshore structures: one-point mooring method, multi-point mooring method and dynamic position maintenance method.

(1) One point mooring method (Fig. 8)

The one-point mooring method is widely used for petroleum unloading, and is widely used instead of the fixed structure method especially in deep water. Fixed structure method has low maintenance cost and high utilization rate of oil unloading operation, while one-point mooring method has high maintenance cost but small initial investment of equipment. The structure of the one-point mooring method is as follows.

① CALM (Catenary Anchor Leg Mooring): Mooring structure from mooring buoys to mooring lines. Most of them are single point mooring, suitable for depths of several tens of meters or less.

② SALM type (Single Anchor Leg Mooring): Mooring to structure with agitated column buoy. Suitable for depths of tens of meters to hundreds of meters.

③ Yoke type: Mooring the structure from weighing buoy of CALM type and SALM type.

④ Turret type: Multi-point mooring cylinders connected to the rotating mechanism in the center of the structure like CALM type buoys. Suitable for hanging risers and cold water conduits.

(2) Multipoint mooring method

The multipoint mooring method is a mooring method for accurately maintaining a marine structure at a predetermined position and preparing a large mooring force, and is employed in an offshore working ship and an oil drilling rig.

There are several types of mooring lines. Wire ropes and chains are used for mooring lines, and an intermediate sinker or intermediate buoy is also provided to stabilize the mooring lines. Anchors target horizontal forces (tangential angle Θ = 0 at the bottom), while sinkers target horizontal forces and vertical forces (connection angle Θ> 0).

(3) dynamic position holding method (Fig. 9)

Mooring by mooring lines is limited in depth, and even in oil rigs, there is little track record for depths of more than a few hundred meters. The dynamic positioning method is used to maintain offshore structures in a fixed position without the use of mooring lines. The GPS (Global Positioning System) is used to detect the position of offshore structures, and calculate and operate the amount of operation of the propeller and auxiliary propeller (Thruster) necessary to maintain a predetermined position.

The degree of dynamic position maintenance is expressed as the percentage of horizontal movement to the depth, about 1% at a depth of about 100 meters. This ratio increases with increasing depth. Especially for offshore structures with risers, this is limited to about 5%. At 10%, it is necessary to carefully maintain the degree of dynamic positioning because the riser will bend and break. The mooring of the marine structure by the mooring method is applied to a depth of more than a hundred meters, but it is advantageous to use the dynamic positioning method with the increase of the depth.

4. Model Test of Floating Offshore Structures

Loads acting on offshore structures are generated by various factors such as waves, currents, wind, and earthquakes as described above. The relative magnitudes of these loads and their effects on the structure depend on the type and form of the structure and the environment of the sea area. In general, wave loading is the dominant factor that determines the design and dynamic behavior of structures. In most cases, the load due to currents is less than about 10-15% of the load due to waves. For structures built in Arctic waters, glacier weight is the dominant element. Wind loads are relatively small, but sometimes they have a significant impact on the behavior of floating structures or fixed structures constructed at relatively deep depths.

The design conditions for these loads are determined deterministically, taking into account the Sea State, which can occur once every 50 to 100 years, and identify the structural characteristics that occur during the reversal of the structure. In order to do so, it is necessary to perform statistical analysis of stochastic approaches with the usual conditions of sea governing.

Thus, in order to manufacture offshore structures, it is important to examine the design conditions of loads in various ways. Therefore, it is very important to conduct experiments with a model and to compare the situation and contents of actual offshore structures.

By the way, the turret mooring apparatus for model experiment vessel of the floating marine structure used in the prior art was large and inconvenient to handle, and the rotation axis between the pedestal and the sensor could be shaken because the structural accuracy was not high and the measurement value was unreliable.

The present invention has been proposed to solve the above problems, it is possible to increase the accuracy in the measurement of tension and force according to the efficient configuration of the turret (Turret), as well as to simplify the problem of waterproof (important) important in model experiments It is an object of the present invention to provide a model test apparatus for floating offshore structures.

Other objects and advantages of the present invention will be described below, which are not limited to the matters set forth in the claims and the disclosure of the embodiments thereof, but also to the broader ranges by means and combinations within the range readily recited therefrom. Add that it will be included.

In order to achieve the above object, the present invention, the side shape is a box-like structure, such as Π, both ends coupled to the bottom of the model test ship, the height adjustable; A 6-axis load cell mounted on the inner ceiling of the cradle; A turret rotating shaft rotated 360 degrees in a state coupled to the six-axis load cell below; We present a model test apparatus for a floating offshore structure including a plurality of single-axis load cells connected to the lower end of a turret rotating shaft.

The model test apparatus of the floating marine structure according to the present invention is easy to assemble and easy to install, it is easy to fit the mass distribution (GM, etc.) of the entire model test ship when the model test. And since there is no loss of force transmitted from the turret's axis of rotation, it is possible to accurately measure small forces in the 6-axis load cell. In addition, it is easy to manufacture by introducing a waterproof system using a waterproof film, it is good to be able to restore quickly in case of damage.

Other effects of the present invention, as well as those described in the above-described embodiments and claims of the present invention, as well as potential effects that may occur within the range that can be easily estimated therefrom and potential advantages that contribute to industrial development It will be added that it will be covered by a wider scope.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible, even if shown on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, the following will describe a preferred embodiment of the present invention, but the technical idea of the present invention is not limited thereto and may be variously modified and modified by those skilled in the art.

Fig. 10 shows the overall appearance of the present invention, Fig. 11 shows the detailed structure of the present invention, Fig. 12 shows the force applied to the present invention by a six-axis load cell, and Fig. 13 shows the waterproof system of the present invention. .

Positioning performance of floating offshore structures is very important because it greatly affects the utilization rate and work efficiency of structures. This is also the case for a model test ship to which the present invention is applied.

The position maintenance method of the model test vessel to which the present invention is applied is a turret mooring method, which is installed between the model test apparatus and the mooring system according to the present invention by installing a rotating structure called a turret in the water surface. It is a mooring method that allows 360 degrees of rotation.

Model experiment apparatus of the floating marine structure according to the present invention, the side shape is a box-like structure, such as Π, both ends are coupled to the bottom of the model test vessel, the height of the cradle 10 is adjustable; A six-axis load cell 20 mounted on an inner ceiling of the cradle 10; A turret rotating shaft 30 rotating 360 degrees in a state coupled to the six-axis load cell 20 below; It comprises a plurality of single-axis load cell 40 is connected to the lower end of the turret rotating shaft 30.

In the present invention, since the cradle 10, the 6-axis load cell 20, and the turret rotating shaft 30 are integrally formed in the model test vessel, the assembly is simple and easy to install.

In the conventional case, there was a disadvantage in that the rotation axis of the turret and the turret should be made separately according to the height of the model experiment vessel, but in the present invention, the height of the cradle 10 is adjusted to flexibly for different model experiment vessels. Applicable

In this case, the height of the holder 10 can be adjusted by replacing the height of the member (A) constituting both sides of the holder 10 by changing the height.

On the other hand, Figure 11 represents the size of the model test apparatus of the floating marine structure according to an embodiment of the present invention as a numerical value, which is a number that can vary in accordance with the size of the model test vessel to which the present invention is applied. Note that this is not a fixed value.

Since the present invention is installed on the bottom of the model test ship, its center of gravity is lower than the center of gravity of the entire model test ship (FIG. 12).

In the conventional case, the weight of the model test apparatus is heavy and its center of gravity is higher than the center of gravity of the model test vessel, so it is inappropriate to match the mass distribution (GM, etc.) and kinematic similarity to be performed before the model test. It was. However, in the case of the present invention, since the center of gravity is lower than the center of gravity of the model test vessel, it is easy to match the mass distribution (GM, etc.) of the entire model test vessel at the time of the model test.

In the case of the present invention, since there is no loss of force transmitted from the turret rotating shaft 30, it is possible to accurately measure up to a small magnitude of force in the six-axis load cell 20. Here, the loss of force means that only a part of the force applied to the turret rotating shaft 30 by the friction force generated between the turret rotating shaft 30 and the hull of the model test ship is measured in the six-axis load cell 20.

A force is a physical quantity that causes a change in shape or a state of motion, such as the velocity of a massed object in physics. The force is the amount of vector with magnitude and direction.

In the model experiment using the present invention, the objective is to accurately measure the external force (wave force, tidal force, wind power, etc.) received by the model test vessel, that is, the model test apparatus of the floating marine structure according to the present invention. In order to accurately measure the external force, it is effective that the transmission distance of the force from the point of action of the external force to the measurement point of the external force is as short as possible, and the force is preferably transmitted to one point.

In the present invention, it is necessary to measure the external force in various directions instead of the external force in one direction (FIG. 12), and a six-axis load cell 20 is used, and as described above, the turret rotating shaft ( 30) was directly coupled under the 6-axis load cell 20, which is the point of measurement of the force.

In addition, in the present invention, a predetermined tolerance B is provided between the turret rotating shaft 30 and the bottom of the model test ship in order to prevent the dispersion of the force generated between the action point of the external force and the measurement point of the external force. In this way, by placing the tolerance (B) it can prevent the phenomenon of hitting or interfering with the bottom (bottom) of the model experiment ship in the course of the turret rotating shaft 30 is lost the dispersion of force. In other words, the force is transferred from one point of action of the external force to one point.

On the other hand, if a predetermined tolerance (B) is placed between the turret rotating shaft 30 and the bottom of the model test vessel as described above, water is introduced into the model test vessel through the tolerance (B). The present invention treated the waterproof film 50 in the tolerance (B) to prevent the inflow of water.

In the existing model test, the silicone waterproofing system was generally used, but in the case of silicone waterproofing, the used silicone tends to halve the force to be actually measured at the point of measurement of the rubber, which results in the reliability of the measured value. There was a problem falling, the present invention is to introduce a method of using a waterproof film 50 having good elasticity and fluidity (Fig. 13).

Existing silicone waterproofing is difficult to take a lot of time and work because it is necessary to remove all the silicon and newly waterproof when the waterproof area is damaged, in the case of the present invention, the waterproof film 50 is easily attached and detached, and quickly restored when damaged You can do it.

In the present invention, in order to measure the tension (Tension Force) applied to each mooring line, the uniaxial load cell 40 is installed at the lower end of the turret rotating shaft 30 that rotates 360 degrees.

The present invention measures the external force received by the model test ship, that is, the model test apparatus of the floating marine structure according to the present invention according to the following scenario (FIG. 12).

External force (wave force, tidal force, wind power, etc.) is generated → The behavior of the model test ship is generated by the external force acting on the model test ship → The external force applied to the model test ship is fixed because each mooring line is fixed to the ground. The 1-axis load cell 40 measures the tension acting in the opposite direction → The 6-axis load cell 20 finally measures the vector sum of the respective tensions measured by the 1-axis load cell 40.

The above description is merely illustrative of the technical idea of the present invention, and various modifications, changes, and substitutions may be made by those skilled in the art without departing from the essential characteristics of the present invention. will be. Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. . The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

1 shows various types of marine structures.

2 shows the shape of a drill ship.

Figure 3 shows the Jack-Up Rig.

4 shows a semi-submersible drilling ship (Semisubmersible).

Figure 5 shows the appearance of Floating Production Storage Offloading (Fpso).

6 shows a state of a jacket.

Figure 7 shows the appearance of the concrete gravity structure (Gbs).

8 shows a one-point mooring method among mooring methods of offshore structures.

Figure 9 shows the dynamic position maintenance method of the mooring method of offshore structures.

Figure 10 shows the overall appearance of the model experiment apparatus of floating marine structures according to the present invention.

11 is a cross-sectional view showing a detailed structure of a model experiment apparatus of a floating marine structure according to the present invention.

Figure 12 shows a state that the force applied to the model experiment apparatus of the floating marine structure according to the present invention is measured by a six-axis load cell.

Figure 13 shows the waterproof system of the model experiment apparatus of the floating marine structure according to the present invention.

<Description of Major Symbols in Drawing>

10: holder

20: 6 axis load cell

30: turret rotation axis

40: single axis load cell

50: waterproof film

Claims (5)

A box-like structure having a lateral shape such as Π, both ends of which are coupled to the bottom of the model test ship, and having a height adjustable cradle; A 6-axis load cell mounted on the inner ceiling of the cradle; A turret rotating shaft rotating 360 degrees in a state of being coupled below the 6-axis load cell; A plurality of single axis load cell connected to the lower end of the turret rotating shaft Model experiment apparatus of a floating marine structure comprising a. The method of claim 1, The height of the cradle is a model experiment apparatus of the floating marine structure, characterized in that for adjusting by changing the height of the members forming both sides of the cradle. The method of claim 1, Model experiment apparatus of the floating marine structure, characterized in that a predetermined tolerance between the turret axis of rotation and the bottom of the model test ship. The method of claim 3, wherein The tolerance model testing apparatus of the floating marine structure, characterized in that the waterproof film treatment. The method of claim 1, The model experiment apparatus of the floating marine structure is a model experiment apparatus of the floating marine structure, characterized in that installed on the bottom of the model experiment ship.

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