A test simulation device for simulating anchoring, dragging of anchors in ship motion

Abstract

The application discloses a kind of test simulation equipment for simulating throwing anchor, dragging anchor in ship movement.The equipment includes water tank and track system, tow control system, anchor operating mechanism and data acquisition and processing system;Water tank and track system provide test water environment and the height of trailer (for simulating ship) from water surface, tow control system drives trailer to move along track, anchor operating mechanism controls anchor dropping position by receiving signal, realizes throwing anchor simulation, data acquisition and processing system monitors anchor chain stress in real time, captures anchor body into water and dragging process by high-speed camera, all data are integrated transmission to control computer by synchronizer, and after processing, output anchor dropping speed curve, anchor chain dragging force peak value and drag anchor trajectory and other parameters.The all test simulation elements of the application are controllable and known, easy to use, can play the role of improving the accuracy and test efficiency of ship throwing anchor, dragging anchor test simulation.

Description

Technical Field

[0001] This invention belongs to the field of ship anchor dropping and dragging tests, and more specifically, relates to a test simulation device for simulating anchor dropping and dragging during ship movement. Background Technology

[0002] In recent years, with the rapid development of marine engineering and maritime transportation, there have been more and more intersections between nearshore shipping routes and submarine tunnels, oil pipelines, cables, optical cables, etc. The impact of ship emergency anchoring and cargo falling into the sea on important submarine projects has become increasingly prominent, becoming an unavoidable factor in engineering design and construction. However, due to the lack of mature calculation methods, the impact of this factor is currently mainly determined through model tests.

[0003] The requirements for this type of test necessitate a device capable of simulating conditions such as ship speed, anchor dropping height, and water depth. This simulation device needs to possess the following characteristics: 1. Accurate simulation control of ship speed; 2. Simulation of anchor dropping height; 3. Simulation of test water depth; 4. A drive system capable of providing sufficient torque to simulate anchor towing. However, existing technology lacks suitable simulation equipment that meets these requirements, thus failing to solve the problem of simulating ship anchor dropping and towing tests. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a test simulation device for simulating anchoring and towing during ship movement. This device, through multi-system coordinated control, achieves accurate simulation of key parameters such as ship speed, anchor drop height, water depth, and anchor chain constraints, and is particularly suitable for evaluating the impact of ship anchoring or towing on shallowly buried seabed structures (such as optical cables, oil pipelines, and immersed tunnels).

[0005] The experimental simulation equipment provided by this invention for simulating anchoring and towing during ship motion includes a water tank and track system, a towing control system, an anchor operating mechanism, and a data acquisition and processing system.

[0006] The water tank and track system includes a test water tank and a liftable track platform; the towing control system includes a power supply, a frequency converter, an AC motor, an adjustable gearbox, and a trailer for simulating a ship. The trailer is mounted on the liftable track platform and is connected to the adjustable gearbox via a cable. The AC motor is powered by the power supply, and the frequency converter receives control signals to control the AC motor. The AC motor outputs adjustable torque through the adjustable gearbox, driving the trailer to move along the track. The anchor operating mechanism is mounted on the trailer and includes an anchoring device, a model anchor, an anchor chain, an anchor chain shaft, and a servo motor. The anchoring device controls the release of the model anchor, which is connected to the anchor chain. The anchor chain is wound around the anchor chain shaft, and the servo motor is used to adjust the position of the anchor chain shaft. The data acquisition and processing system monitors the anchor chain force in real time, captures the model anchor entering the water and the towing process, and outputs the anchor drop speed curve, anchor chain drag force, and anchor trajectory.

[0007] According to a preferred embodiment of the present invention, the data acquisition and processing system includes a tension sensor, a high-speed camera group, and a control computer; the tension sensor is connected in series on the anchor chain to monitor the anchor chain force in real time; the high-speed camera is installed on the trailer or on the test water tank to capture the anchor body entering the water and the towing process; the control computer generates control commands according to preset working conditions to control the operation of the towing control system and the anchor operating mechanism, and at the same time, the control computer collects data from the tension sensor and the high-speed camera group, processes and outputs the anchor drop speed curve, anchor chain drag force, and anchor trajectory.

[0008] The present invention also provides a method for simulating anchoring and towing during ship motion based on the aforementioned experimental simulation equipment, which includes the following steps:

[0009] Before the equipment is put into operation, the sediment material is filled into the test water tank and water is injected according to the preset simulated water depth and sediment thickness; the height of the liftable track platform is adjusted according to the preset anchoring height.

[0010] The trailer is installed on the track, and the anchor chain shaft is installed on the trailer. The axial position of the anchor chain shaft can be adjusted by a servo motor to simulate the position of the actual ship's anchor chain locker. The anchoring device is fixed on the trailer, and the trailer is connected to an adjustable gearbox through a guide cable. The frequency converter receives control signals to control the AC motor to achieve ship speed adjustment.

[0011] At the start of the test simulation, the control computer controlled the AC motor through the frequency converter, causing the adjustable gearbox to accelerate the trailer until it reached the set target speed and then maintained a constant speed.

[0012] When the trailer arrives at the preset anchoring point, the control computer triggers the anchoring device to release the model anchor and simultaneously starts data acquisition; a high-speed camera records the anchor's entry posture into the water, the anchor's position during the anchoring process, the moment of bottom contact, and the anchor chain's shape; a tension sensor monitors the peak tension of the anchor chain; the tension sensor and camera data are synchronized in time; each working condition is repeated ≥5 times until the data standard deviation is <5%; based on the obtained data, the anchoring speed curve, the anchoring trajectory, and the anchor chain drag force-time curve are plotted and analyzed.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0014] (1) This invention can achieve synchronous and precise control of ship speed, anchoring height, and water depth, solving the problem of error amplification caused by parameter coupling in traditional methods. For example, the adjustable track and chain shaft position are linked to ensure that the anchor chain release trajectory is consistent with the geometry of the actual ship.

[0015] (2) By simulating the low-speed anchor dragging condition of a ship with an AC motor and an adjustable gearbox, and combining the real-time feedback of the anchor chain dragging force, the sudden change in resistance during the seabed anchor dragging process is accurately reproduced.

[0016] (3) Synchronously collect kinematic and dynamic data, use time alignment technology to eliminate sensor phase difference, generate anchoring speed-time curve and impact force spectrum, and provide high confidence input for the impact-resistant design of seabed structure.

[0017] (4) Integrated control supports preset quantitative parameters, shortens test preparation time, and enhances repeatability; modular design facilitates the replacement of anchor types (Hall anchor, Spek anchor, etc.) and adapts to the verification requirements of different classification societies.

[0018] (5) Real-time analysis and feedback of anchor drag force, real-time monitoring of drag force during anchoring and towing, simulation of actual ship deceleration during anchoring, and real-time adjustment of ship speed through gearbox to achieve a realistic reproduction of the ship's anchoring, towing and stopping process. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the experimental simulation equipment of the present invention.

[0020] In the diagram, the components are: 1. Test water tank; 2. Adjustable bracket; 3. Track; 4. Power supply and frequency converter; 5. AC motor; 6. Adjustable gearbox; 7. Cable guide; 8. Trailer; 9. Anchoring device; 10. Anchor chain; and 11. Model anchor. Detailed Implementation

[0021] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0022] The experimental simulation equipment provided in this embodiment is used to simulate the processes of dropping and dragging anchors during ship movement, in order to obtain the motion trajectory of the anchor during the dropping process and the anchor chain tension during the dragging process under the simulated working conditions. Figure 1 As shown, the experimental simulation equipment includes: a water tank and track system, a towing control system, an anchor operating mechanism, and a data acquisition and processing system.

[0023] like Figure 1 As shown, the water tank and track system consists of a test water tank 1 and a liftable track platform. The test water tank 1 is a transparent glass tank with tempered glass sidewalls for high-speed camera observation. The bottom is laid with a sedimentary layer (thickness ≥ 0.5m) to simulate the interaction between the anchor and the seabed, mimicking a sandy / clay seabed. The test water tank 1 is filled with water to a level proportionally reduced to the actual water depth. The liftable track platform includes multiple vertically arranged adjustable supports 2 and a horizontally arranged track 3. The track 3 is fixed by the adjustable supports 2, and the horizontal track is bolted to the adjustable supports. The installation height of the horizontal track on the adjustable supports is adjustable. The liftable track precisely controls the initial height of the anchor from the water surface by adjusting its height.

[0024] The towing control system includes a power supply and frequency converter 4, an AC motor 5, an adjustable gearbox 6, and a trailer 8 for simulating a ship. The trailer 8 is mounted on the track 3 of the liftable track platform. The AC motor 5 is powered by the power supply and controlled by the frequency converter receiving control signals. The AC motor 5 outputs adjustable torque through the gearbox 6, driving the trailer 8 to move along the track. The trailer 8 is connected to the adjustable gearbox 6 via a guide cable 7. The towing control system simulates the ship's speed (0-15 knots continuously adjustable) by adjusting the gearbox gears and records the trailer's horizontal speed in real time.

[0025] The anchor operating mechanism is mounted on the trailer and includes an anchoring device 9, a model anchor 11, an anchor chain 10, an anchor chain shaft, and a servo motor. The anchoring device 9 controls the release of the model anchor. The model anchor 11 is connected to the anchor chain 10, and the anchor chain 10 is wound around the anchor chain shaft. The servo motor is used to adjust the position of the anchor chain shaft. The data acquisition and processing system monitors the anchor chain force in real time, captures the process of the model anchor entering the water and being towed, and outputs the anchoring speed curve, the anchor chain dragging force, and the anchoring trajectory.

[0026] In one specific embodiment of the present invention, the data acquisition and processing system includes a tension sensor, a high-speed camera array, and a control computer. The tension sensor is connected in series with the anchor chain to monitor the anchor chain force in real time. The high-speed camera is mounted on the trailer or on the test water tank to capture the anchor body entering the water and the towing process. The control computer generates control commands according to preset working conditions to control the towing control system and the anchor operating mechanism. Simultaneously, the control computer collects data from the tension sensor and the high-speed camera array, processes the data, and outputs the anchor drop speed curve, anchor chain drag force, and anchor trajectory. The guide cable is used for towing the trailer and also serves as a power supply line and signal transmission line. The control computer transmits control commands to the anchor operating mechanism through the guide cable and acquires data from the tension sensor through the guide cable.

[0027] In one specific embodiment, the model anchor is made of ferromagnetic material, and the anchoring device is a relay. Initially, the model anchor is attached to the anchoring device. When the trailer moves to the designated anchoring position at a set speed, the control computer of the data acquisition and processing system outputs an anchoring signal, which is transmitted to the anchoring device via the guide cable. The relay is de-energized, and the model anchor is released. The friction between the guide rail and the trailer is greater than the resistance of the simulated ship moving in the water. If the friction between the guide rail and the trailer is too small, the speed of the trailer after anchoring will be faster than the inertial speed of the actual ship after anchoring, making the simulation results inaccurate. After the anchoring device of this invention releases the model anchor, the control computer controls the towing control system to apply a real-time varying pulling force to the trailer to adjust the speed of the towing guide cable, so that the speed of the trailer is consistent with the actual ship's speed under its own inertia after anchoring. The actual ship's speed under its own inertia after anchoring can be obtained in advance by consulting data or calculation based on the simulated sea conditions, ship type, ship size, water holding capacity, etc.

[0028] Preliminary equipment installation for this experiment:

[0029] Before the experiment, a liftable track platform was erected along the long axis of the water tank. Adjustable supports were fixed to concrete bases on both sides of the water tank with anchor bolts. The water depth and the height of the horizontal track were adjusted to simulate the water depth and freeboard conditions of the ship under test. A trailer was installed on the horizontal track, and an anchor chain shaft was installed on the trailer. The axial position of the chain shaft could be adjusted by a servo motor to simulate the position of the actual ship's anchor chain compartment. An anchoring device was fixed on the trailer. This device included an electromagnetic release mechanism (relay) that could control the anchor dropping after receiving the anchoring signal. Then, an AC motor was connected to the trailer drive wheel via an adjustable gearbox, and a frequency converter received control signals to adjust the ship speed.

[0030] The data acquisition system includes a tension sensor and a high-speed camera. The tension sensor is connected in series between the end of the anchor chain and the chain shaft; the high-speed camera can be fixedly mounted on the side of the water tank or fixed to a trailer by a bracket.

[0031] Preparation for this experiment:

[0032] The computer inputs the test conditions, including ship parameters such as speed; the lifting rail is adjusted to the corresponding anchoring height of the ship, and the chain shaft is positioned at the target position; the trailer is reset to the front end of the horizontal rail (the AC motor, adjustable gearbox, etc. are arranged at the rear end of the horizontal rail), the model anchor is suspended on the anchoring device, ready to receive the signal and anchor; the data acquisition unit completes calibration and standardization.

[0033] The experiment was conducted as follows:

[0034] The control computer starts an AC motor to drive an adjustable gearbox to accelerate the trailer to the target anchoring speed and then maintains a constant speed. When the trailer reaches the preset anchoring point, the anchoring device is triggered to release the model anchor, and data acquisition is started simultaneously. A high-speed camera records the anchor's entry attitude into the water, the anchor's position during the anchoring process, the moment of bottom contact, and the anchor chain's shape. A tension sensor monitors the anchor chain's drag force over time. The tension sensor and camera data are synchronized in time. The acceleration of the actual ship is calculated by the real-time collected anchor chain drag force, and the speed is obtained by integration. The gearbox is then adjusted to decelerate, simulating the actual ship's deceleration and stopping process.

[0035] During the experiment, the anchor chain towing force was collected in real time after anchoring. The acceleration of the simulated ship under the measured anchor chain towing force was calculated, the ship's deceleration process was simulated, and the transmission was controlled to adjust the trailer's speed, achieving a realistic reproduction of the ship's anchoring, towing, and stopping processes. The system collected the anchor towing force signal in real time during the experiment and used a low-pass filter to eliminate high-frequency noise. The filtered anchor towing force (F...) d ) and simulated ship mass (M) and ship drag (R) h Substitute these values ​​into the dynamic equations to solve for the ship's instantaneous acceleration (a):

[0036] Ma(t) = -F d (t)-R h (v s )

[0037] In the formula, t represents the duration, and v s This represents the instantaneous horizontal speed of the ship; a speed reference value is generated by integrating a(t) and used for drive control.

[0038] In addition, the control computer calculates the anchoring motion characteristics based on high-speed image sequences using the inter-frame difference method:

[0039] v y =Δy / Δt

[0040] v x =Δx / Δt

[0041] In the formula, vy v x Δy and Δx represent the vertical and horizontal velocity components of the anchor body, respectively. Δy and Δx represent the vertical and horizontal positional differences of the anchor body in two adjacent images recorded by the high-speed camera, respectively. Δt is the shooting time interval of the high-speed camera.

[0042] By combining tension sensor data with the anchor chain release length, a dragging anchor resistance model is fitted:

[0043]

[0044] In the formula, F d The measured drag force is given by k, which is the proportionality coefficient fitted based on the experimental data.

[0045] Finally, by integrating the anchoring mass m, the anchor's final velocity v, and seabed material parameters, the impact kinetic energy is calculated and the subsequent effects are assessed.

[0046]

[0047] In the formula, E k Let m be the kinetic energy of the anchor hitting the seabed, m be the mass of the anchor, and v be the kinetic energy of the anchor hitting the seabed. y and v x Vector sum.

[0048] In the actual experimental simulation process, each working condition was repeated ≥5 times until the data standard deviation was <5%. Based on the large amount of data obtained, it is possible to draw the anchoring trajectory diagram, analyze the anchor chain drag force-time curve, and assess the anchoring effect and impact. The assessment of the anchoring effect and impact evaluates whether the maximum tension exerted by the anchor body on the hull through the anchor chain can support the stability of the hull. If it can support the stability, it indicates that the anchoring effect is good.

[0049] Although the embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art, under the guidance of the present invention, can make many other forms without departing from the spirit and scope of the claims of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A test simulation device for simulating anchoring and dragging anchor during ship motion, characterized in that, The equipment includes a water tank and track system, a towing control system, an anchor operating mechanism, and a data acquisition and processing system. The water tank and track system includes a test water tank and a liftable track platform; the towing control system includes a power supply, a frequency converter, an AC motor, an adjustable gearbox, and a trailer for simulating a ship. The trailer is mounted on the liftable track platform and is connected to the adjustable gearbox via a cable. The AC motor is powered by the power supply, the frequency converter receives control signals to control the AC motor, and the AC motor outputs adjustable torque through the adjustable gearbox to drive the trailer along the track. The bottom of the test water tank is laid with a sedimentary layer simulating a sandy / clay seabed. The liftable track platform includes multiple vertically arranged adjustable supports and a horizontal track. The horizontal track is fixed to the adjustable supports by bolts, and the installation height of the horizontal track on the adjustable supports is adjustable. The initial height of the model's anchorage from the water surface is controlled by adjusting the height of the liftable track. The anchor operating mechanism is mounted on the trailer and includes an anchoring device, a model anchor, an anchor chain, an anchor chain shaft, and a servo motor. The anchoring device is used to control the release of the model anchor. The model anchor is connected to the anchor chain, which is wound around the anchor chain shaft. The servo motor is used to adjust the position of the anchor chain shaft. The data acquisition and processing system monitors the anchor chain force in real time, captures the process of the model anchor entering the water and being dragged, and outputs the anchor drop speed curve, anchor chain drag force and dragging trajectory. The data acquisition and processing system includes a tension sensor, a high-speed camera group, and a control computer. The tension sensor is connected in series with the anchor chain to monitor the anchor chain force in real time. The high-speed camera is set on the trailer or on the test water tank to capture the anchor body entering the water and the towing process. The control computer generates control commands according to preset working conditions to control the operation of the towing control system and the anchor operating mechanism. At the same time, the control computer collects data from the tension sensor and the high-speed camera group, processes the data, and outputs the anchor drop speed curve, anchor chain drag force, and anchor trajectory.

2. The test simulation equipment for simulating anchoring and dragging anchor during ship motion according to claim 1, characterized in that, The cable is used to tow the trailer, and also serves as a power supply line and signal transmission line; the control computer transmits control commands to the anchor operating mechanism through the cable; and acquires data from the tension sensor through the cable.

3. The test simulation equipment for simulating anchoring and dragging anchor during ship motion according to claim 1, characterized in that, The control computer obtains the horizontal movement speed of the trailer in real time based on the winding and unwinding speed of the guide cable; the speed of the ship is simulated by adjusting the gearbox gear, and the speed is continuously adjustable from 0 to 15 knots.

4. The test simulation equipment for simulating anchoring and dragging anchor during ship motion according to claim 1, characterized in that, The model anchor is made of ferromagnetic material, and the anchoring device is a relay. In the initial state, the model anchor is attached to the anchoring device. When the trailer moves to the designated anchoring position at a set speed, the control computer of the data acquisition and processing system outputs an anchoring signal, which is transmitted to the anchoring device via a guide cable. The relay is de-energized, and the model anchor is released.

5. The test simulation equipment for simulating anchoring and dragging anchor during ship motion according to claim 4, characterized in that, The friction between the horizontal track and the trailer is greater than the resistance of the simulated ship moving in the water; after the anchoring device releases the model anchor, the control computer controls the speed of the towing control system to drag the guide cable so that the speed of the trailer is consistent with the actual ship's speed under its own inertia after anchoring.

6. A method for simulating anchoring and towing during ship motion using the experimental simulation equipment described in claim 1, characterized in that, Includes the following steps: Before the equipment is put into operation, the sediment material is filled into the test water tank and water is injected according to the preset simulated water depth and sediment thickness; the height of the liftable track platform is adjusted according to the preset anchoring height. The trailer is installed on the track, and the anchor chain shaft is installed on the trailer. The axial position of the anchor chain shaft can be adjusted by a servo motor to simulate the position of the actual ship's anchor chain locker. The anchoring device is fixed on the trailer, and the trailer is connected to an adjustable gearbox through a guide cable. The frequency converter receives control signals to control the AC motor to achieve ship speed adjustment. At the start of the test simulation, the control computer controlled the AC motor through the frequency converter, causing the adjustable gearbox to accelerate the trailer until it reached the set target speed and then maintained a constant speed. When the trailer arrives at the preset anchoring point, the control computer triggers the anchoring device to release the model anchor and simultaneously starts data acquisition; a high-speed camera records the anchor's entry posture into the water, the anchor's position during the anchoring process, the moment of bottom contact, and the anchor chain's shape; a tension sensor monitors the peak tension of the anchor chain; the tension sensor and camera data are synchronized in time; each working condition is repeated ≥5 times until the data standard deviation is <5%; based on the obtained data, the anchoring speed curve, the anchoring trajectory, and the anchor chain drag force-time curve are plotted and analyzed.

7. The method according to claim 6, characterized in that, After anchoring, the control computer collects the anchor chain drag force in real time. The signal is then filtered by a low-pass filter to eliminate high-frequency noise, and the filtered anchor drag force F is then calculated. d Compared with the simulated ship mass M and ship running resistance R h Substitute these values ​​into the dynamic equations to solve for the ship's instantaneous acceleration a: ； In the formula, t represents the duration, and v s Indicates the instantaneous horizontal speed of a ship; by analyzing... The integral generates a speed reference value, which is used to drive the adjustable transmission to adjust the trailer's travel speed, thus realistically reproducing the process of a ship anchoring, towing anchor, and stopping.

Images