Testing device for measuring horizontal displacement of mooring drilling ship under different ice attack angles

Abstract

The invention relates to a test device for measuring horizontal displacement of a mooring drilling ship under different ice attack angles, which comprises a bracket, an annular slide rail, at least one group of mooring cables and a suspender structure, and is characterized in that the annular slide rail is fixedly connected to the bracket; a sliding groove is formed in the annular sliding rail, and at least one sliding block matched with the sliding groove is arranged on the sliding groove. The suspender structure comprises a suspender main body, and the upper end of the suspender main body is fixedly connected with the sliding block; the suspender body is provided with an upper fixed pulley and a lower fixed pulley, one end of the mooring rope is connected to the model ship and sequentially bypasses the upper fixed pulley and the lower fixed pulley, and a heavy object is hung at the other end of the mooring rope; a variable stiffness spring is connected in series on the mooring cable, and the variable stiffness spring is used for simulating the nonlinear characteristic of the mooring cable.

Description

Technical Field

[0001] The present invention relates to the field of ship mooring test devices, and particularly to a test device for measuring the horizontal displacement of a moored ship at different ice attack angles. Background Art

[0002] Drilling ships operating in ice areas usually adopt the method of anchoring and mooring to achieve fixation and limit the movement of the hull. Compared with drilling ships operating in open water areas, drilling ships in ice areas are vulnerable to collisions with floating ice, resulting in increased translational displacement, which affects the positioning of the drill pipe and further affects the normal progress of the operation. Therefore, to ensure the safety of drilling operations, polar drilling ships need to determine the safe ice conditions based on the limit value of translational displacement to ensure that the hull displacement does not exceed the design limit value under such ice conditions. Based on this, it is necessary to conduct ice tank test research on polar moored drilling ships.

[0003] However, there are many limitations in the existing ice tank test environment. Especially, the water depth of the tank is usually relatively shallow, which is difficult to meet the conditions of anchoring and mooring, and the installation and operation are inconvenient. In addition, during the test process, it is necessary to push ice to impact the model ship, which easily causes the movement of the cable, thus affecting the test results.

[0004] To solve the above problems, there is an urgent need for a new type of dry mooring device to realize the mooring test in the ice tank through the method of above-water installation. This device has the characteristics of convenient installation and disassembly, and can flexibly adjust the position of the mooring point and the ice-attack angle of the model ship. Summary of the Invention

[0005] The purpose of the present invention is to provide an ice tank ship mooring test device, which realizes the dry mooring of the model ship through a boom, is convenient for installation, especially in an ice tank with extremely shallow water depth. The mooring cable is horizontally connected to the model ship, and a spring with variable stiffness is connected in series to simulate the nonlinear characteristics of the real mooring cable. The boom is connected to the upper annular slide rail through a slider, so as to achieve the purpose of convenient installation, disassembly and rotation of the ice-attack angle of the model ship. Finally, the displacement of the model ship's movement is monitored in real time through the arranged optical capture system.

[0006] To achieve the above purpose, the present invention provides the following solutions:

[0007] An experimental device for measuring the horizontal displacement of a moored drilling ship at different ice angles of attack, characterized in that it includes a bracket, an annular slide rail, at least one set of mooring cables and a boom structure. The annular slide rail is fixedly connected to the bracket; the annular slide rail is provided with a chute, and at least one slider matching the chute is arranged on the chute; the boom structure includes a boom body, and the upper end of the boom body is fixedly connected to the slider; the boom body is provided with an upper fixed pulley and a lower fixed pulley. One end of the mooring cable is connected to the model ship, and after passing around the upper fixed pulley and the lower fixed pulley in sequence, a heavy object is suspended at the other end; a variable stiffness spring is connected in series on the mooring cable, and the variable stiffness spring is used to simulate the non-linear characteristics of the mooring cable.

[0008] Further: The bracket is provided with a buckle, and the annular slide rail is connected to the bracket through the buckle. When the buckle is loosened, the annular slide rail can be rotated to any angle, so as to change the ice-facing angle of the model ship.

[0009] Further: The boom body is a telescopic slide rod.

[0010] Further: The experimental device further includes an optical capture system for capturing the translational displacement of the model ship and outputting the result.

[0011] Due to the adoption of the above technical solutions, the present invention has the following advantages: 1. Through the ingenious design of the boom structure, the present invention realizes a dry mooring structure, which can be installed on water, facilitating engineering installation and extending the service life; 2. Compared with underwater mooring, the present invention avoids the disturbance of the underwater mooring cable during the ice pushing process, ensures the integrity of the ice floe, and improves the accuracy of the measurement results of the ice tank test; 3. The annular slide rail structure of the present invention simplifies the process of changing the bow angle of the model ship during the test, greatly saves the test duration, and reduces the test error caused by the ice floe rewarming; 4. The telescopic design of the boom structure of the present invention enables the experimental device to face test conditions with various water depths, saving test costs. Description of the Drawings

[0012] Figure 1 is the front view of the experimental device of the present invention.

[0013] Figure 2 is the top view of the experimental device of the present invention.

[0014] Figure 3 is the cross-sectional view of the annular slide rail of the present invention.

[0015] Explanation of the reference numerals in the figure: 1 is the bracket; 1-1 is the buckle; 2 is the annular slide rail; 2-1 is the chute; 3 is the slider; 4 is the boom structure; 4-1 is the mooring cable; 4-2 is the lower fixed pulley; 4-3 is the variable stiffness spring; 4-4 is the upper fixed pulley; 4-5 is the heavy object; 4-6 is the telescopic slide rod; 5 is the optical capture system. Detailed implementation mode

[0016] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0017] As Figures 1 to 3 shown, the present invention mainly includes a bracket 1; a buckle 1-1; an annular slide rail 2; a chute 2-1; a slider 3; a boom structure 4; a mooring cable 4-1; a lower fixed pulley 4-2; a variable stiffness spring 4-3; an upper fixed pulley 4-4; a heavy object 4-5; a telescopic slide rod 4-6; and an optical capture system 5.

[0018] As Figure 1 shown, the bracket 1 of the present invention spans across the ice pool and is fixed at both ends of the pool wall.

[0019] As Figure 2 shown, a controllable buckle 1-1 is fixed at the upper end of the bracket 1, and the buckle 1-1 is connected to the annular slide rail 2. When the buckle 1-1 is opened, the annular slide rail 2 can be rotated to any angle, so as to realize the function of changing the ice-facing angle of the model ship.

[0020] As Figure 3 shown, a chute 2-1 is opened inside the annular slide rail 2, the chute 2-1 is adapted to the slider 3, and the slider 3 can slide arbitrarily on the annular slide rail 2 and is abutted against the chute 2-1 through a long screw, so as to realize the purpose of convenient installation, disassembly and changing the position of the mooring point.

[0021] As Figure 1 shown, the boom structure 4 is used to hang the mooring cable 4-1. The main body of the boom structure 4 is composed of a telescopic slide rod 4-6. The upper end of the telescopic slide rod 4-6 is welded to the slider 3, and an upper fixed pulley 4-4 and a lower fixed pulley 4-2 are respectively connected to the top and bottom thereof. One end of the mooring cable 4-1 is fixed on the model ship, and after passing around the lower fixed pulley 4-2 and the upper fixed pulley 4-4 in sequence, a heavy object 4-5 is connected to the other end.

[0022] As Figure 1 shown, a variable stiffness spring 4-3 is connected in series on the mooring cable 4-1. The variable stiffness spring 4-3 is used to simulate the non-linear characteristics of the mooring cable. In the real situation, it is to simulate the horizontal stiffness of the mooring cable, because the drilling ship mainly undergoes translational displacement and no heave motion under the action of sea ice.

[0023] As Figure 1 shown, the weight 4-5 connected to the other end of the mooring cable 4-1 can be adjusted arbitrarily, which is convenient for operation, and further realizes the purpose of pre-tensioning the mooring cable.

[0024] As Figure 1As shown, the optical capture system 5 is arranged outside the bracket 1 to capture the translational displacement of the model ship in real time and output the results, and finally judge under what sea ice conditions the moored drilling ship will generate translational displacement exceeding the design limit value based on these results.

[0025] Through this design, the present invention can be applied to test conditions with various water depths, saving test costs.

[0026] Test steps

[0027] (1) Stably install the bracket 1 at the starting end of the ice pool so that it straddles and is fixed on both sides of the pool wall. Fix the annular slide rail 2 on the bracket 1 through the buckle 1-1. Loosen the long screw on the slider 3 so that it can freely slide in the chute 2-1 in the annular slide rail 2 to prepare for adjusting the position of the boom later.

[0028] (2) Place the model ship in the ice pool and make its waterline consistent with the horizontal plane by adding counterweights. Adjust the heading of the model ship to the target direction according to the set ice attack angle in the test.

[0029] (3) Adjust the length of the telescopic slide rod 4-6 so that its lower end is flush with a position twice the ice thickness above the waterline of the model ship. Then slide the slider 3 to position the boom structure 4 at the bow and stern thruster areas of the model ship respectively, and fix its position by tightening the long screw. Connect the mooring cable 4-1 to the corresponding position of the model ship and adjust the weight of the weight 4-5 to achieve the pre-tensioned state of the mooring cable. Ensure that the variable stiffness spring 4-3 is connected in series in the mooring cable to simulate the non-linear horizontal stiffness characteristic.

[0030] (4) Before the test starts, turn on the optical capture system 5 and arrange markers on the model ship to complete the initial position calibration. Subsequently, push the ice block to impact the model ship at a set speed through the ice pushing device. Under the action of the ice force, the translational displacement generated by the model ship will be recorded in real time by the optical capture system 5 for subsequent data analysis.

[0031] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An experimental device for measuring the horizontal displacement of a moored drilling ship at different ice angles of attack, characterized in that : It includes a bracket, a circular slide rail, at least one set of mooring cables and a boom structure. The circular slide rail is fixedly connected to the bracket; a chute is provided on the circular slide rail, and at least one slider matching the chute is arranged on the chute; the boom structure includes a boom body, and the upper end of the boom body is fixedly connected to the slider; the boom body is provided with an upper fixed pulley and a lower fixed pulley. One end of the mooring cable is connected to the model ship, and after sequentially passing around the upper fixed pulley and the lower fixed pulley, a heavy object is suspended at the other end; a variable stiffness spring is connected in series on the mooring cable, and the variable stiffness spring is used to simulate the nonlinear characteristics of the mooring cable.

2. The test device for measuring the horizontal displacement of a moored drilling ship at different ice angles of attack according to claim 1, characterized in that : The bracket is provided with a buckle, and the circular slide rail is connected to the bracket through the buckle. When the buckle is loosened, the circular slide rail can be rotated to any angle, so as to change the ice-facing angle of the model ship.

3. The test device for measuring the horizontal displacement of a moored drilling ship at different ice angles of attack according to claim 1, characterized in that : The boom body is a telescopic slide rod.

4. The test device for measuring the horizontal displacement of a moored drillship at different ice angles of attack according to claim 1, characterized in that : The test device further includes an optical capture system for capturing the translational displacement of the model ship and outputting the result.

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