Lifting platform scaling model experiment device and method for simulating cable reversing of marine flexible pipe cable

Abstract

The invention discloses a lifting platform scaling model experiment device and method for simulating cable reversing of a marine flexible pipe cable, the device comprises a lifting system, a supporting structure, a power mechanism and a sliding mechanism, and the lifting system simulates the height difference of two pipe laying ships; the supporting structure and the sliding mechanism are fixed to the lifting system and used for planning a cable reversing route. The power system is fixed to the lifting system and used for fixing and storing submarine cables. By monitoring the rotating speed and angle physical quantity of the roller, the device has important significance for accurately controlling experiment influence factors and ensuring the accuracy and repeatability of the experiment, can measure the tensile stress and bending stress in the cable reversing process, is an improvement of the submarine cable reversing experiment testing technology, measures more parameters, and has a good application prospect. And the experiment benefit can be maximized.

Description

Technical Field

[0001] The invention belongs to the field of marine platforms, and in particular relates to a scaled model experimental device and method for a lifting platform for simulating cable inversion of marine flexible pipe cables. Background Art

[0002] With the continuous growth of demand for offshore oil production, the demand for marine flexible cables is increasing due to their good bending properties, and they are widely used in the transportation and storage of marine oil and gas resources. The cable laying operation refers to the process of winding the cable continuously on the reel on the ship at the dock through the loading arm and guide rollers on the pipe-laying ship after the cable is manufactured by the manufacturer and passed the factory test. During the cable laying process, the flexible cables are subjected to complex bending, torsion and coupled loads, which may cause the flexible cables to be overloaded or even damaged and fail. Therefore, it is necessary to study the influence of different parameters on the mechanical properties of the submarine cable during the cable laying process.

[0003] In the process of cable laying, in order to make the cable meet the strength requirements of the cable under various loads, it is necessary to design the parameters according to the effects of factors such as the drum speed, cable winding angle and the tension force at the end of the flexible cable. Since the cable laying path is too long, the important parts are divided into sections, namely, the cable entry section and the bending and turning section. Therefore, the changes in the mechanical properties of the cable in the straight transport section, the bending and turning section and the cable entry section in the cable laying path are focused on.

[0004] However, the actual cable laying process is too large, and considering the geometric nonlinear characteristics of the cable, the structural model is complex, and the accuracy of the results obtained by theoretical and numerical simulation methods is difficult to guarantee; and the traditional experiments of proportional models are costly, have a long experimental cycle, and are difficult to conduct. Therefore, a scaled model experimental device that can simulate the cable laying path is needed to test the influence of the drum speed and winding angle on the mechanical characteristics of the cable when it is in place through experimental methods, ensure the rationality of parameter design, improve the stability of the cable in place, and propose an optimized design scheme for the cable laying process.

[0005] At present, there is no research on the mechanical characteristics of flexible cables in the process of cable laying in the domestic research on mechanical behavior. Therefore, there is an urgent need for a simulation study that can simulate the influence of the drum speed, winding angle and tension force at the end of the flexible cable on the mechanical characteristics of the flexible cable during the cable laying path, so as to provide a useful reference for the selection of relevant parameters for the actual cable laying operation. Summary of the invention

[0006] The object of the present invention is to provide a scaled model experimental device and method for a lifting platform for simulating cable reversal of a marine flexible pipe cable.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A scaled model experimental device of a lifting platform for simulating cable laying of a marine flexible cable comprises a lifting system, a supporting structure, a power mechanism and a sliding mechanism; the lifting system comprises an upper platform, a built-in platform and an external platform of a bottom platform; the sliding mechanism comprises at least four platform slide rails, on which a supporting structure is mounted via sliders, and at the same time, the platform slide rails are slidably connected to four side edges of the upper platform and the external platform to arrange the path of the submarine cable and adjust the spacing of the cable laying; the power mechanism comprises a tensioning system, a loading arm and a drum installed on the upper platform, a driving motor and a reel installed on the external platform of the bottom platform, the reel being connected to the driving motor via a coupling to achieve cable laying and laying; the tensioning system straightens the submarine cable and guides it to the loading arm, and the loading arm lays the submarine cable into the drum via the supporting structure to achieve cable storage.

[0009] Furthermore, the lifting system also includes a pitch-adjusting gear, a lifting arm, a threaded block and a ratchet; the upper platform and the bottom platform are connected via a lifting arm, and the lifting arm is used to control the vertical movement of the platform; the pitch-adjusting gears are meshed with each other and are installed on the side wall of the bottom platform, and are used to control the movement of the lifting arm on the guide rail, and realize the self-locking function of the device through the ratchet.

[0010] Furthermore, two parallel guide rails and a horizontal axis fixed on the platform are provided on the bottom surface of the upper platform and the built-in platform of the bottom platform; the distance between the built-in platform and the external platform is maintained at 5-20 cm, and the built-in platform is connected to the upper platform through a lifting arm; the lifting arm includes two groups of fixed support arms and sliding support arms, and the fixed support arms and the sliding support arms are hinged together in the middle to form an X-shaped structure, and the fixed support arms have through holes at both ends, and are both installed on the bottom surface of the upper platform and the horizontal axis of the built-in platform, and the sliding support arms have pulleys at both ends, and are both placed on the guide rails on both sides of the bottom surface of the upper platform and the bottom platform.

[0011] Furthermore, the sliding mechanism also includes a base and an L-shaped slider installed on the slider; at least one slider is installed on each platform slide rail, and L-shaped sliders are installed at both ends; the four sides of the upper platform and the four sides of the external platform are provided with slide rails, and the L-shaped slider is slidably connected to the slide rails to drive the platform slide rails to slide; a travel switch is installed on one of the platform slide rails.

[0012] Furthermore, limiters and bumpers are provided at both ends of the platform slide rail.

[0013] Furthermore, the supporting structure includes rollers, a launching bridge and guide rollers; the launching bridge is installed on the side of the upper platform, and the edge plates on both sides ensure the normal laying of the submarine cable and prevent lateral displacement from causing tilting; the rollers are connected to the slider base of the sliding mechanism through a connecting sleeve to adjust the height of the rollers, and the submarine cable passes through the middle of the rollers; the guide rollers are installed on the loading arm to guide the submarine cable into the drum.

[0014] Furthermore, the method is implemented by citing a scaled model experimental device of a lifting platform for simulating cable laying of marine flexible pipe cables; two pipe-laying vessels are scaled down to the upper platform and the bottom platform of the experimental device at a scale ratio of 1:10; first, a driving motor drives the reel to release the cable and sets the speed of the reel, and the cable is supported and transmitted through rollers according to the set path, and the pipe cable is turned through a steering arc plate; due to the height difference between the two pipe-laying vessels, the vertical direction is turned through the launching bridge, and the loading arm is controlled to guide the guide rollers to the drum, and the motor at the upper end of the drum provides power to drive the drum to reel in the cable, thereby completing the simulation of the cable laying process; a tension sensor is used to measure the submarine cable during the cable laying process, and the measured data is statistically analyzed to determine the optimal cable laying path at a specified speed; and switching between different paths is achieved by adjusting the slider and the platform rail.

[0015] Furthermore, the cable laying path is divided into sections according to spatial characteristics: pipe and cable barrel section, straight transportation section, curved turning section, launching bridge turning section, lower laying section, plane conversion transition section and roller fixing section.

[0016] Furthermore, the submarine cable model is 0.1 m long, 0.05 m wide, and has a Young's modulus of 2000 MPa. The bending radius parameter of the submarine cable path is 0.2 m, and the roller parameters are a radius of 0.1 m, a roller speed of 0.07 m / s, and a roller rotation speed of 1.5 rad / s.

[0017] Furthermore, the bending radius is an important parameter for the bending degree and reliability of the submarine cable, and the calculation formula is:

[0018] R min =(D2)K

[0019] Wherein: D is the outer diameter of the submarine cable, K is the safety factor, and the value range of K is 0.8-1.2; the angle of the submarine cable wound on the reel should be between 0° and 30°; the submarine cable should be wound tightly on the reel to avoid loosening and slipping. The control system controls the working parameters of the motion system, including the end tension force and the submarine cable path; changing these parameters allows the lifting platform to complete the cable-reversing simulation test with different cable-releasing speeds and motion parameters of different paths.

[0020] The beneficial effects of the present invention are:

[0021] 1. The system of the present invention can effectively measure the drum speed, the cable winding angle and the tension at the end of the flexible cable. The drum speed and winding angle have a great influence on the mechanical properties during the cable reeling process. Monitoring the speed and angle physical quantities is of great significance for accurately controlling the influencing factors of the experiment and ensuring the accuracy and repeatability of the experiment.

[0022] 2. The system of the present invention can measure the stress of the cable in different cable-falling sections, and can quantitatively understand the cable-falling process. At the same time, it can provide more accurate initial parameters of the cable, thus providing a reference for numerical simulation.

[0023] 3. The system of the present invention can measure the tensile stress and bending stress during the cable laying process, which is an improvement in the test technology of submarine cable laying experiments. Measuring more parameters can maximize the experimental benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the overall structure of the cable-reversing lifting platform of the present invention;

[0025] Figure 2 It is a schematic diagram of the transmission system structure of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings.

[0027] according to Figure 1-2 The present invention discloses a horizontal motion simulation experimental device for an underwater ejection system, which mainly comprises a lifting system, a supporting structure, a power mechanism and a sliding mechanism; specifically comprises a lifting platform, a drum 1, a lifting arm 2, a lead screw 3, a driving motor 4, a coupling 5, a reel 6, a motor bracket 7, a base 8, a slider 9, a bottom platform 10, a platform slide rail 11, a threaded block 12, a tripod 13, a ratchet 14, a submarine cable 15, a pitch-adjusting gear 16, a guide rail 17, a launching bridge 18, an upper platform 19, a roller 20, a coupling sleeve 21, a tensioning system 22, a loading arm 23, a guide roller 24, a connector 30 and an L-shaped slider 32.

[0028] The lifting platform includes an upper platform 19 and a bottom platform 10. The bottom platform 10 includes an internal platform and an external platform, which is used to simulate the vertical movement and reciprocating linear motion of the submarine cable. The side of the bottom internal platform is connected with a handle, a pitch-adjusting gear 16 and a ratchet 14. The pitch-adjusting gear 16 controls the movement of the threaded block 12 on the lead screw 3, and is used to control the movement of the lifting arm (2) on the guide rail (17) to achieve the change of the platform height difference. The tripod 13 is fixed by screws to the mutually meshing pitch-adjusting gears 16, and is inlaid with the wedge block where the ratchet 14 is located. The upper platform (19) and the bottom internal platform are connected through the lifting arm (2), and the lifting arm (2) is used to control the vertical movement of the platform. The self-locking function of the device is installed and realized through the ratchet (14).

[0029] The lifting arm 2 includes two groups of fixed support arms and sliding support arms, and the fixed support arms and the sliding support arms are hinged together in the middle to form an X-shaped structure. The fixed support arms have through holes at both ends, and are both installed on the bottom surface of the upper platform (19) and the horizontal axis of the built-in platform. The sliding support arms have pulleys at both ends, and are both placed on the bottom surface of the upper platform (19) and the two side guide rails (17) of the bottom platform (10).

[0030] At least two platform slide rails 11 are installed on the upper platform 19 and the bottom external platform. The two platform slide rails 11 are cross-shaped. Each platform slide rail 11 has at least one slider 9. At least one slider (9) is installed on each platform slide rail (11). L-shaped sliders (32) are installed at both ends. The four sides of the upper platform (19) and the four sides of the external platform are provided with slide rails. The L-shaped sliders (32) are slidably connected to the slide rails to drive the platform slide rails (11) to slide and realize lateral and longitudinal movement. Anti-collision blocks are arranged at both ends of the slide rails to prevent the ejection system from colliding with other structures. A travel switch is installed on one of the platform slide rails (11).

[0031] The slider 9 is provided with a base 8 , one end of the connecting sleeve 21 is connected to the roller 20 via a screw, and the other end cooperates with the base 8 via a sleeve, so that the height of the roller 20 can be adjusted up and down.

[0032] The coupling 5 is connected to the driving motor 4 of the bottom external platform to drive the reel 6 to release the submarine cable 15. The driving motor 4 is installed on the motor bracket 7. The tensioning system 22 extends the other end of the submarine cable 15 to the loading arm 23, and guides it to the guide roller 24 through the loading arm 23, and is coiled on the drum 1 of the upper platform to realize cable storage.

[0033] The tensioning system 22 is installed on the upper platform 19. The hydraulic motor rotates forward and the pipeline moves backward to keep the pipeline tension not less than the minimum allowable tension value without generating longitudinal movement. It is used to control the tension of the submarine cable 15.

[0034] The edge plates on both sides of the launching bridge 18 can ensure the normal laying of the submarine cable 15 and prevent the lateral displacement from causing tilting; the slider 8 matched with the roller 20 is provided with a variety of paths for planning the cable laying route.

[0035] The platform model is a cable-reversed scale experimental model with a scale ratio of 1:10, which can realize the analysis of the mechanical behavior of the submarine cable 15 under different drum 1 rotation speeds and winding angles; the platform is composed of a flat plate and a limit axis, the platform is a cube, and the limit axis is a rotating body.

[0036] Embodiment 1:

[0037] The two pipe-laying vessels are scaled down to the upper and lower planes of the lifting platform in the device, and the pitch-adjusting gear 16 is used to control the threaded block 12 to move on the lead screw 3 to achieve the change of the platform height difference, so as to simulate the working height environment of the submarine cable 15 between the pipe-laying vessels; the tripod 13 fixes the pitch-adjusting gear 12 by screws, and completes self-locking through the ratchet 13; the tensioner is scaled down to the tensioning system 20, which provides tension for the submarine cable 14 to prevent the submarine cable 14 from wearing and slipping, so that it can complete the cable retraction and release according to the specified path; the submarine cable laying path is scaled down to the combination of the slider 9 and the platform slide rail 11, and the path can be changed by moving the slider 9, and then measured by the tension sensor, and the experimental data is statistically analyzed to determine the optimal path; the drum 1 and the reel 6 are scaled down to ensure the retraction and release of the submarine cable 15; the loading arm 23 and the guide roller 24 are scaled down to achieve the guided loading of the submarine cable 15 and store it in the drum 1; the launching bridge 18 is scaled down to the side edge structure to protect the submarine cable from lateral slippage. The proportional scale model of the roller 20 ensures the horizontal support of the submarine cable, and the roller is fixed to the base 8 through the coupling sleeve 21 to achieve height adjustment.

[0038] The experimental method of the present invention is as follows: first, the driving motor 4 drives the reel 6 to release the cable and selects the rotation speed of the reel 6, and the cable is supported and transmitted by the roller 20 according to the set path, and the cable is turned through the steering arc plate; due to the height difference between the two ships, the cable is turned in the vertical direction through the launching bridge 18, and under the control of the loading arm 23, the cable is guided by the guide roller 24 to the drum 1, and the motor at the upper end of the drum 1 provides power to drive the drum 1 to reel in the cable, completing the simulation of the cable reeling process. The cable 15 is measured by a tension sensor during the cable reeling process, and the measured data is statistically analyzed to determine the optimal cable reeling path at the specified rotation speed; the switching of different paths is achieved by adjusting the slider 8 and the platform rail 11.

[0039] Since the cable laying path is too long, its important path is segmented according to its spatial characteristics. The path is divided into the tube cable barrel section, straight transportation section, curved turning section, water bridge turning section, lower laying section, plane conversion transition section and roller fixed section. Since the failure forms of submarine cables in the cable laying process are mainly tensile failure and bending failure, the tensile failure is caused by the gravity of the flexible cable itself and the excessive tension during transportation, which mainly occurs in the straight transportation section of the flexible cable; and the bending failure is caused by the bending radius of the bending turning section and the submarine cable entering the barrel section during the cable laying process. The submarine cable failure. Taking the submarine cable model with parameters of 0.1m in length, 0.05m in width and 2000MPa in Young's modulus as the research target, the submarine cable path bending radius parameter is 0.2m, the design parameters of the drum are radius 0.1m, drum speed 0.07m / s, and drum speed 1.5rad / s.

[0040] The cross-sectional data of the flexible cable and the cable path parameter design are shown in Table 1. The bending radius is an important parameter for the bending degree and reliability of the submarine cable. The calculation formula is:

[0041] R min =(D2)K

[0042] Where: D is the outer diameter of the submarine cable, K is the safety factor, and the value range of K is 0.8 to 1.2. Considering the material parameters of the submarine cable and environmental factors, K is taken as 0.8.

[0043] Table 1 Flexible cable cross-section data and cable path parameters

[0044]

[0045] In the production process of the flexible cable, the winding angle of the cable on the reel 6 is generally determined according to the cable specifications and the diameter of the reel. Usually, the angle of the cable on the reel 6 should be between 0° and 30°, so that the submarine cable 15 can be tightly wound on the reel 6 without loosening or slipping.

[0046] The control system controls the working parameters of the motion system, including the terminal tension force, the cable path, etc. By changing these parameters, the lifting platform can complete the cable-reversing simulation test with different cable-releasing speeds and different paths of motion parameters.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A scaled model experimental device for a lifting platform of a marine flexible cable simulating cable reversal, characterized in that: The invention comprises a lifting system, a supporting structure, a power mechanism and a sliding mechanism; the lifting system comprises an upper platform (19), a bottom platform (10) and an internal platform and an external platform; the sliding mechanism comprises at least four platform slide rails (11), the supporting structure is installed on the platform slide rails (11) through sliders (9), and the platform slide rails (11) are slidably connected with four sides of the upper platform and the external platform to arrange the path of the submarine cable (15) and adjust the cable release spacing; the power mechanism comprises a mounting The tensioning system (22), loading arm (23) and drum (1) of the upper platform (19), the driving motor (4) and the reel (6) installed on the external platform of the bottom platform (10), the reel (6) being connected to the driving motor (4) through a coupling (5) to realize cable laying; the tensioning system (22) straightens the submarine cable (15) and guides it to the loading arm (23), and the loading arm (23) lays the submarine cable (15) into the drum (1) through the supporting structure to realize cable storage.

2. A scaled model experimental device for a lifting platform for simulating cable reversal of a marine flexible cable according to claim 1, characterized in that: The lifting system further comprises a pitch-adjusting gear (16), a lifting arm (2), a threaded block (12) and a ratchet (14); the upper platform (19) and the bottom platform (10) are connected via the lifting arm (2), and the lifting arm (2) is used to control the vertical movement of the platform; the pitch-adjusting gears (16) are meshed with each other and are mounted on the side wall of the bottom platform (10), and are used to control the movement of the lifting arm (2) on the guide rail (17), and realize the self-locking function of the device via the ratchet (14).

3. A scaled model experimental device for a lifting platform for simulating cable reversal of a marine flexible cable according to claim 2, characterized in that: The bottom surface of the upper platform (19) and the built-in platform of the bottom platform are both provided with two parallel guide rails (17) and a horizontal axis fixed on the platform; the distance between the built-in platform and the external platform is maintained at 5-20 cm, and the built-in platform is connected to the upper platform through a lifting arm; the lifting arm includes two groups of fixed support arms and sliding support arms, and the fixed support arms and the sliding support arms are hinged together in the middle to form an X-shaped structure, and the fixed support arms have through holes at both ends, and are both installed on the bottom surface of the upper platform (19) and the horizontal axis of the built-in platform, and the sliding support arms have pulleys at both ends, and are both placed on the guide rails (17) on the bottom surface of the upper platform (19) and the two sides of the bottom platform (10).

4. The scale model experimental device of a lifting platform for simulating cable reversal of a marine flexible cable according to claim 1, characterized in that: The sliding mechanism also includes a base (8) and an L-shaped slider (32) installed on the slider (9); at least one slider (9) is installed on each platform slide rail (11), and L-shaped sliders (32) are installed at both ends; the four sides of the upper platform (19) and the four sides of the external platform are provided with slide rails, and the L-shaped slider (32) is slidably connected to the slide rails to drive the platform slide rails (11) to slide; a travel switch is installed on one of the platform slide rails (11).

5. The scaled model experimental device of a lifting platform for simulating cable reversal of a marine flexible cable according to claim 4, characterized in that: Limiters and bumpers are provided at both ends of the platform slide rail (11).

6. A scaled model experimental device for a lifting platform for simulating cable reversal of a marine flexible cable according to claim 1 or 4, characterized in that: The support structure comprises rollers (20), a launching bridge (18) and guide rollers (24); the launching bridge is installed on the side of the upper platform (19), and the edge plates on both sides ensure the normal laying of the submarine cable (15) and prevent the lateral displacement from causing tilting; the rollers (20) are connected to the slider base (8) of the sliding mechanism through a connecting sleeve (21) to adjust the height of the rollers (20), and the submarine cable (15) passes through the middle of the rollers (20); the guide rollers (24) are installed on the loading arm (23) for guiding the submarine cable (15) into the drum (1).

7. A scaled model test method for a lifting platform for simulating cable reversal of a marine flexible cable, characterized in that: The method is implemented by using the scaled model experimental device of the lifting platform for simulating the reversing of the marine flexible pipe cable as described in claims 1 to 6; two pipe-laying vessels are scaled down to the upper platform (19) and the bottom platform (10) of the experimental device at a scale ratio of 1:10; firstly, the driving motor (4) drives the reel (6) to work and release the cable and sets the rotation speed of the reel (6); the cable is supported and transmitted by the roller (20) according to the set path, and passes through the steering arc plate to complete the steering of the pipe cable; due to the height difference between the two pipe-laying vessels, The cable is turned in the vertical direction by a launching bridge (18), and is guided by a guide roller (24) under the control of a loading arm (23) to a drum (1). The motor at the upper end of the drum (1) provides power to drive the drum (1) to reel in the cable, thereby completing the simulation of the cable reeling process. The submarine cable (15) is measured by a tension sensor during the cable reeling process, and the measured data is statistically analyzed to determine the optimal cable reeling path at a specified rotation speed. The switching between different paths is achieved by adjusting a slider (9) and a platform slide rail (11).

8. The method for testing a scaled model of a lifting platform for simulating the reversal of a marine flexible cable according to claim 7, characterized in that: The cable laying path is divided into sections according to spatial characteristics: a pipe and cable barrel section, a straight transportation section, a curved turning section, a launching bridge turning section, a lower laying section, a plane conversion transition section and a roller fixing section.

9. The method for testing a scaled model of a lifting platform for simulating the reversal of a marine flexible cable according to claim 8, characterized in that: The submarine cable model is 0.1m long, 0.05m wide, with a Young's modulus of 2000MPa. The bending radius parameter of the submarine cable path is 0.2m. The roller parameters are radius 0.1m, roller speed 0.07m / s, and roller rotation speed 1.5rad / s.

10. The method for testing a scaled model of a lifting platform for simulating cable reversal of a marine flexible cable according to claim 8, characterized in that: The bending radius is an important parameter for the bending degree and reliability of submarine cables. The calculation formula is: R min＝ ( D 2)K In the formula: D is the outer diameter of the submarine cable, K is the safety factor, and the value range of K is 0.8 to 1.2; the angle at which the submarine cable (15) is wound on the reel (6) should be between 0° and 30°; the submarine cable (15) is tightly wound on the reel (6) to avoid loosening and slipping, and the control system controls the working parameters of the motion system, including the end tension force and the submarine cable path; By changing these parameters, the lifting platform can complete the cable-falling simulation test with different cable-releasing speeds and motion parameters of different paths.

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