Mooring cable sheath wear test device

Abstract

The invention discloses a mooring cable sheath wear test device, which comprises a box body, a seabed is laid in the box body, the seabed comprises a fine sand grain layer, a medium sand grain layer and a coarse sand grain layer which are laid in sequence, and a first slide way and a second slide way are horizontally arranged on two sides of the box body respectively. The mooring cable is erected between the first slide way and the second slide way and slides back and forth along the first slide way and the second slide way, and the mooring cable is in contact friction with the fine sand layer, the medium sand layer and the coarse sand layer so as to measure the abrasion degree of the mooring cable. According to the mooring cable sheath wear test device provided by the invention, the seabed is laid in the box body, so that the wear frequency and frequency between the mooring cable and the seabed are obtained, and the wear amount of the mooring cable in the service life cycle is evaluated, thereby playing a reference role in later use, maintenance and repair of the mooring cable; meanwhile, the monitoring frequency in the mooring cable application process can be reduced, the corrosion risk is reduced, the structure is simple, the test efficiency is high, and the overall mooring cable application performance is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of mooring cable sheath wear test, and in particular relates to a mooring cable sheath wear test device. Background Art

[0002] At present, most floating production storage and offloading units (FPSOs) are positioned by mooring. During the installation and operation of submarine cables, the mooring cables will wear on the seabed of different geological types due to the violent dynamic response under the action of wave and current loads, and the outer sheath of the submarine cable will experience severe wear. The wear and damage of the outer sheath of the mooring cable will cause corrosion and fracture of the armor layer, which directly affects its mechanical properties. It is necessary to simulate the mooring cable and the seabed and conduct wear test analysis on the mooring cable sheath. The simulation test structure in the existing technology is complex and the simulation test efficiency is low.

[0003] Therefore, it is urgent to design a mooring cable sheath wear test device to solve the above-mentioned problems of complex structure and low efficiency of mooring cable and seabed simulation test. Summary of the invention

[0004] In order to solve the technical problems of complex structure and low efficiency of mooring cable and seabed simulation test mentioned in the background technology, a mooring cable sheath wear test device is provided to solve the above problems.

[0005] To achieve the above purpose, the specific technical solution of the mooring cable sheath wear test device of the present invention is as follows: A mooring cable sheath wear test device comprises a box body, a seabed is laid inside the box body, the seabed comprises a fine sand layer, a medium sand layer and a coarse sand layer laid in sequence, a first slideway and a second slideway are horizontally arranged on both sides of the box body, a mooring cable is erected between the first slideway and the second slideway, the mooring cable slides back and forth along the first slideway and the second slideway, the mooring cable contacts and rubs against the fine sand layer, the medium sand layer and the coarse sand layer, so as to measure the wear degree of the mooring cable.

[0006] Furthermore, the mooring cable includes a mooring cable body, on which a first sheath and a second sheath are sequentially sheathed. The second sheath contacts and rubs against fine sand particles, medium sand particles and coarse sand particles. When the second sheath is worn and the first sheath is exposed, the wear risk point of the mooring cable is calibrated.

[0007] Further, the size of fine sand particles is 75 μm, the layer thickness of fine sand particles is 0.7 m, the size of medium sand particles is 425 μm, the layer thickness of medium sand particles is 1.2 m, and the size of coarse sand particles is 2 mm, the layer thickness of coarse sand particles is 1.1 m.

[0008] Furthermore, the box body is made of 20mm 45# steel plate, and the length, width and height of the box body are 2000mm, 1500mm and 3000mm respectively.

[0009] Furthermore, a first connecting shaft and a second connecting shaft are respectively arranged at both ends of the mooring cable. The first connecting shaft is slidably arranged in the first slideway, and the second connecting shaft is slidably arranged in the second slideway.

[0010] Furthermore, it also includes a first bearing and a second bearing, the first bearing is arranged on the first connecting shaft, the second bearing is arranged on the second connecting shaft, the first bearing slides in the first slideway, and the second bearing slides in the second slideway.

[0011] Furthermore, it also includes a driving component, which is connected to the mooring cable to drive the mooring cable to slide between the first slideway and the second slideway along the length direction of the first slideway and the second slideway.

[0012] Furthermore, it also includes a connecting frame, one end of which is connected to the driving assembly, and the other end of the connecting frame is connected to the mooring cable.

[0013] Furthermore, the connecting frame includes a first connecting plate, a second connecting plate and a third connecting plate, the first connecting plate is arranged between the second connecting plate and the third connecting plate, the first connecting plate is connected to the driving assembly, the end of the second connecting plate away from the first connecting plate is connected to the first connecting shaft, and the end of the third connecting plate away from the first connecting plate is connected to the second connecting shaft.

[0014] Furthermore, it also includes a limiting plate, which is arranged between the second connecting plate and the third connecting plate to limit the movement of the mooring cable.

[0015] The mooring cable sheath wear test device of the present invention has the following advantages: A seabed is laid in a box, the seabed includes a fine sand layer, a medium sand layer and a coarse sand layer laid in sequence, a first slide and a second slide are horizontally arranged on both sides of the box respectively, the mooring cable is erected between the first slide and the second slide, the mooring cable slides back and forth along the first slide and the second slide, the mooring cable contacts and rubs with the fine sand layer, the medium sand layer and the coarse sand layer to measure the wear of the mooring cable, and the wear frequency and frequency between the mooring cable and the seabed are obtained, and the wear amount of the mooring cable during its service life is evaluated, which serves as a reference for the later use, maintenance and repair of the mooring cable. At the same time, it can reduce the monitoring frequency and corrosion risk during the application process of the mooring cable, and can also provide feedback to guide the improvement of the plastic coating thickness and materials in the manufacturing process of the mooring cable. The simulation test device has a simple structure and high simulation test efficiency, which plays a vital role in improving the application performance of the entire mooring cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of a mooring cable sheath wear test device of the present invention; Figure 2 It is a schematic diagram of the cross-sectional structure of the mooring cable of the present invention.

[0017] Description of the markings in the figure: 100. mooring cable; 101. mooring cable body; 102. first layer of sheath; 103. second layer of sheath; 1. box; 2. seabed; 3. first slideway; 4. second slideway; 5. first connecting shaft; 6. second connecting shaft; 7. first bearing; 8. second bearing; 9. connecting frame; 91. first connecting plate; 92. second connecting plate; 93. third connecting plate; 94. limit plate; 10. driving rod. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0019] Those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present invention and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0020] Please refer to the attached Figure 1 To Attachment Figure 2 The mooring line sheath wear test apparatus of the present invention is described.

[0021] At present, most floating production storage and offloading (FPSO) units use steel cable mooring to achieve positioning. The first generation of mooring cables are mainly made of pure steel wires, and use their own coatings, such as galvanized and galvanized aluminum alloy, to resist seawater corrosion. Affected by wind and flow loads, the mooring cables not only have to withstand seawater corrosion, but also wear and tear with the seabed. When the coating is worn away, the steel base of the mooring cable is exposed to seawater, causing chemical and electrical corrosion. As the corrosion intensifies, the mechanical properties of the mooring cable will be reduced, and even worse, it will cause the mooring cable to break.

[0022] The reasons that affect the corrosion of materials in seawater environment are very complex, including chemical factors, salinity distribution of seawater, pH value of seawater, seawater flow rate and temperature, various animals, plants and microorganisms in the marine environment, and the attached organisms and seabed sediment environment are more related to seawater corrosion. Mooring cable manufacturers are trying to explore a metal material or coating material that can be used for marine use, with new stainless steel as the representative development situation: its corrosion resistance can be improved by the following three aspects: increasing the content of Ni and Cr; reducing the content of C to improve corrosion resistance; adding Mo to stainless steel to improve the resistance of the surface passivation film, but the alloy is expensive and the strength of the steel wire is not high, and the long-term corrosion resistance is not good, so the practical application prospects are slim. Studies have found that polyethylene has very stable chemical properties and excellent resistance to seawater erosion, and will not undergo electrochemical corrosion. Therefore, the second-generation mooring cable coated with a layer of high-density or medium-density polyethylene was born on the basis of the first-generation pure steel cable.

[0023] The mooring cable is placed in the sea water for at least 20 years. Driven by wind and wave loads, the mooring cable and the seabed 2 wear each other. In different sea areas, the roughness of the sand on the seabed 2 is different, and the wear rate is also different. If the wear state between the mooring cable and the seabed 2 can be simulated, the wear degree of the mooring cable during use can be evaluated, which will greatly promote the normal use and maintenance of the mooring cable in the later period. This data can be used to monitor, maintain and repair the steel cable within the set service life of the mooring cable, reduce the frequency of underwater robot monitoring and avoid the risk of sheath wear.

[0024] At present, the wear test analysis of mooring cable sheath is carried out. The simulation test structure in the prior art is complex and the simulation test efficiency is low. Therefore, it is urgent to design a mooring cable sheath wear test device to solve the above-mentioned problems.

[0025] like Figure 1 As shown, the mooring cable sheath wear test device of the present invention comprises a box body 1, a seabed 2 is laid inside the box body 1, and the seabed 2 comprises a fine sand layer, a medium sand layer and a coarse sand layer laid in sequence, and a first slideway 3 and a second slideway 4 are horizontally arranged on both sides of the box body 1, and a mooring cable 100 is erected between the first slideway 3 and the second slideway 4. The mooring cable 100 slides back and forth along the first slideway 3 and the second slideway 4, and the mooring cable 100 contacts and rubs with the fine sand layer, the medium sand layer and the coarse sand layer to measure the wear degree of the mooring cable 100. In this embodiment, the box body 1 is made of 20mm 45# steel plate, and the length, width and height of the box body 1 are 2000mm, 1500mm and 3000mm respectively.

[0026] A seabed 2 is laid in a box body 1, and the seabed 2 includes a fine sand layer, a medium sand layer and a coarse sand layer laid in sequence. A first slideway 3 and a second slideway 4 are horizontally arranged on both sides of the box body 1, respectively. A mooring cable 100 is erected between the first slideway 3 and the second slideway 4, and the mooring cable 100 slides back and forth along the first slideway 3 and the second slideway 4. The mooring cable 100 contacts and rubs with the fine sand layer, the medium sand layer and the coarse sand layer to measure the wear degree of the mooring cable 100, and the wear frequency and frequency between the mooring cable 100 and the seabed 2 are obtained, and the wear amount of the mooring cable 100 during its service life is evaluated, which serves as a reference for the later use, maintenance and repair of the mooring cable 100. At the same time, it can reduce the monitoring frequency and corrosion risk during the application process of the mooring cable 100, and can also provide feedback to guide the improvement of the plastic coating thickness and materials during the manufacturing process of the mooring cable 100. The simulation test device has a simple structure and high simulation test efficiency, which plays a vital role in improving the application performance of the entire mooring cable 100.

[0027] Further, if Figure 2 As shown, the mooring cable 100 includes a mooring cable body 101, and a first layer of sheath 102 and a second layer of sheath 103 are sequentially sheathed outside the mooring cable body 101. The second layer of sheath 103 contacts and rubs with fine sand, medium sand and coarse sand. After the second layer of sheath 103 is worn and the first layer of sheath 102 is exposed, the wear risk point of the mooring cable 100 is calibrated. After the second layer of sheath 103 and the seabed 2 are worn against each other, the first layer of sheath 102 wrapped by the second layer of sheath 103 is exposed. After the first layer of sheath 102 is exposed, the second layer of sheath 103 is repaired in time to avoid damage to the mooring cable body 101 after the first layer of sheath 102 is worn and damaged, thereby improving the performance of the mooring cable body 101.

[0028] With the development and application of steel cable manufacturing technology, a layer of sheath of the same material is added on the basis of the second-generation mooring cable 100. The first sheath 102 and the second sheath 103 are both high-density or medium-density polyethylene, so as to effectively resist the wear between the seabed 2. In order to monitor the wear degree of the sheath of the mooring cable 100, the colors of the first sheath 102 and the second sheath 103 are inconsistent. Usually, the first sheath 102 is red and the second sheath 103 is yellow. When it is monitored that the second sheath 103 is worn to the color of the first sheath 102, repair measures can be taken in time to repair the second sheath 103, which can effectively avoid the corrosion caused by the penetration of seawater into the steel base of the mooring cable 100, thereby greatly improving the service life of the mooring cable 100.

[0029] Furthermore, a simulated seabed 2 structure is placed in the box 1. The seabed 2 includes three layers of sand, namely fine sand, medium sand and coarse sand. The size of the fine sand is 75 μm, the layer thickness of the fine sand is 0.7 m, the size of the medium sand is 425 μm, the layer thickness of the medium sand is 1.2 m, the size of the coarse sand is 2 mm, and the layer thickness of the coarse sand is 1.1 m.

[0030] Further, if Figure 1 As shown, a first connecting shaft 5 and a second connecting shaft 6 are respectively provided at both ends of the mooring cable 100, the first connecting shaft 5 is slidably arranged in the first slideway 3, and the second connecting shaft 6 is slidably arranged in the second slideway 4. In order to simulate the effect of contact and friction between the mooring cable 100 and the seabed 2, the mooring cable sheath wear test device in the present invention also includes a first bearing 7 and a second bearing 8, the first bearing 7 is arranged on the first connecting shaft 5, and the second bearing 8 is arranged on the second connecting shaft 6, the first bearing 7 slides in the first slideway 3, and the second bearing 8 slides in the second slideway 4, so that the mooring cable 100 can slide in the first slideway 3 and the second slideway 4.

[0031] Further, if Figure 1 As shown, the mooring cable sheath wear test device in the present invention further includes a driving assembly, which is connected to the mooring cable 100 to drive the mooring cable 100 to slide between the first slideway 3 and the second slideway 4 along the length direction of the first slideway 3 and the second slideway 4. The driving assembly can be a combination of a driving cylinder and a crank rocker mechanism to drive the mooring cable 100 to move in the first slideway 3 and the second slideway 4, or a driving motor or a combination with other structures, as long as it can drive the mooring cable 100 to move in the first slideway 3 and the second slideway 4 to achieve contact friction with the seabed 2.

[0032] Further, if Figure 1 As shown, the mooring cable sheath wear test device in the present invention also includes a connecting frame 9, one end of the connecting frame 9 is connected to the driving assembly, and the other end of the connecting frame 9 is connected to the mooring cable 100. Specifically, the connecting frame 9 includes a first connecting plate 91, a second connecting plate 92 and a third connecting plate 93, the first connecting plate 91 is arranged between the second connecting plate 92 and the third connecting plate 93, the first connecting plate 91 is connected to the driving assembly, the end of the second connecting plate 92 away from the first connecting plate 91 is connected to the first connecting shaft 5, and the end of the third connecting plate 93 away from the first connecting plate 91 is connected to the second connecting shaft 6. A driving rod 10 is arranged on the first connecting plate 91, and the driving rod 10 is connected to the driving assembly. The driving assembly drives the connecting frame 9 to move relative to the box 1, thereby causing the mooring cable 100 to slide along the first slide 3 and the second slide 4, so as to realize the contact friction between the mooring cable 100 and the seabed 2, thereby realizing the wear test of the mooring cable 100.

[0033] Further, if Figure 1 and Figure 2As shown, in order to limit the moving distance of the mooring cable 100 when the driving component drives the mooring cable 100 to move along the first slide 3 and the second slide 4, so that the mooring cable 100 moves within a specified travel range, the mooring cable sheath wear test device in the present invention also includes a limiting plate 94, which is arranged between the second connecting plate 92 and the third connecting plate 93 to limit the movement of the mooring cable 100.

[0034] The mooring cable sheath wear test device of the present invention records each back and forth movement as one time, and records and measures the change in the diameter of the mooring cable 100 every 1000 times. When the second layer of sheath 103 is worn to the first layer of sheath 102, it is recorded as a dangerous point. It is also used as the number of times that the mooring cable 100 needs to be paid attention to in actual application, and maintenance and repair suggestions can be put forward. It is also used to verify the feasibility of the thickness of the second layer of sheath 103, which has a counter-effect on the manufacture of the mooring cable 100, and suggestions are put forward to increase the thickness or improve the sheath material.

[0035] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A mooring cable sheath wear test device, characterized in that: The invention comprises a box body, in which a seabed is laid, and the seabed comprises a fine sand layer, a medium sand layer and a coarse sand layer laid in sequence, a first slideway and a second slideway are respectively horizontally arranged on both sides of the box body, a mooring cable is erected between the first slideway and the second slideway, and the mooring cable slides back and forth along the first slideway and the second slideway, and the mooring cable contacts and rubs against the fine sand layer, the medium sand layer and the coarse sand layer to measure the wear degree of the mooring cable.

2. The mooring cable sheath wear test device according to claim 1, characterized in that: The mooring cable comprises a mooring cable body, on the outside of which a first sheath and a second sheath are sequentially sheathed. The second sheath contacts and rubs against fine sand, medium sand and coarse sand. When the second sheath is worn and the first sheath is exposed, the wear danger point of the mooring cable is calibrated.

3. The mooring cable sheath wear test device according to claim 1, characterized in that: The size of fine sand particles is 75μm, and the layer thickness of fine sand particles is 0.7m. The size of medium sand particles is 425μm, and the layer thickness of medium sand particles is 1.2m. The size of coarse sand particles is 2mm, and the layer thickness of coarse sand particles is 1.1m.

4. The mooring cable sheath wear test device according to claim 1, characterized in that: The box body is made of 20mm 45# steel plate, and the length, width and height of the box body are 2000mm, 1500mm and 3000mm respectively.

5. The mooring cable sheath wear test device according to claim 1, characterized in that: A first connecting shaft and a second connecting shaft are respectively arranged at both ends of the mooring cable. The first connecting shaft is slidably arranged in the first slideway, and the second connecting shaft is slidably arranged in the second slideway.

6. The mooring cable sheath wear test device according to claim 5, characterized in that: It also includes a first bearing and a second bearing. The first bearing is arranged on the first connecting shaft, and the second bearing is arranged on the second connecting shaft. The first bearing slides in the first slideway, and the second bearing slides in the second slideway.

7. The mooring cable sheath wear test device according to claim 1, characterized in that: It also includes a driving assembly connected to the mooring cable to drive the mooring cable to slide between the first slideway and the second slideway along the length direction of the first slideway and the second slideway.

8. The mooring cable sheath wear test device according to claim 7, characterized in that: It also includes a connecting frame, one end of which is connected to the driving assembly, and the other end of which is connected to the mooring cable.

9. The mooring cable sheath wear test device according to claim 8, characterized in that: The connecting frame includes a first connecting plate, a second connecting plate and a third connecting plate. The first connecting plate is arranged between the second connecting plate and the third connecting plate, the first connecting plate is connected to the driving assembly, the end of the second connecting plate away from the first connecting plate is connected to the first connecting shaft, and the end of the third connecting plate away from the first connecting plate is connected to the second connecting shaft.

10. The mooring cable sheath wear test device according to claim 9, characterized in that: It also includes a limiting plate, which is arranged between the second connecting plate and the third connecting plate to limit the movement of the mooring cable.

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