A tuned mass damper device for a cylindrical FPSO

Abstract

The application discloses a tuned mass damper device for a cylindrical FPSO and belongs to the technical field of damping shock absorption, which comprises an FPSO main body, an annular sleeve and a damper, the annular sleeve is arranged outside the FPSO main body, the damper is arranged between the FPSO main body and the annular sleeve, the FPSO main body comprises a platform moon pool, a conical heeling plate and a hanging ear I, the conical heeling plate is arranged below the platform moon pool, and the hanging ear I is arranged above the conical heeling plate. The tuned mass damper device for the cylindrical FPSO can increase the waterline width of the overall structure, so that the swing movement of the FPSO main body is further inhibited.

Description

Technical Field

[0001] This invention relates to the field of damping and vibration reduction technology, and in particular to a tuned mass damping device for a cylindrical FPSO. Background Technology

[0002] Cylindrical floating production storage and offloading (FPSO) units, due to their rotationally symmetrical design, possess excellent anisotropic hydrodynamic performance and are insensitive to environmental loads from different directions in terms of their swaying degrees of freedom. Therefore, this structure is suitable for mooring systems with lower technical difficulty and cost, thereby improving overall economic efficiency. Furthermore, it features large oil storage capacity, simple design, and short construction period, making it particularly suitable for the development of small or marginal oil fields. In recent years, cylindrical FPSOs have been widely used in offshore oil and gas development due to these advantages.

[0003] However, the cylindrical structure of FPSOs results in significant vertical motion response, posing a potential threat to the safety of drilling and oil production operations and potentially exacerbating structural fatigue damage, thus affecting their long-term service performance. Therefore, effective measures are urgently needed to suppress the vertical motion of cylindrical FPSOs, thereby improving their operational stability and safety. Summary of the Invention

[0004] The purpose of this invention is to provide a tuned mass damping device for a cylindrical FPSO to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides a tuned mass damping device for a cylindrical FPSO, comprising an FPSO body, an annular sleeve, and a damper. The annular sleeve is disposed outside the FPSO body, and the damper is disposed between the FPSO body and the annular sleeve. The FPSO body includes a platform moon pool, a conical heave plate, and a first lug. The conical heave plate is disposed below the platform moon pool, and the first lug is disposed above the conical heave plate.

[0006] Preferably, the annular sleeve includes an inner outer shell, an upper outer shell, an outer outer shell, and a bottom outer shell. The upper outer shell and the bottom outer shell are respectively disposed at the top and bottom ends of the inner outer shell, and the inner outer shell and the outer outer shell are disposed between the upper outer shell and the bottom outer shell.

[0007] Preferably, the internal space of the annular sleeve is divided by twelve vertically arranged main bulkheads to form twelve independent compartments. Each compartment is equipped with three vertically arranged transverse control bulkheads and one vertically arranged longitudinal control bulkhead.

[0008] Preferably, the transverse and longitudinal swaying bulkheads are provided with water-permeable holes at the bottom and middle, respectively, and each of the compartments is equipped with a ballast pump at the bottom.

[0009] Preferably, the inner outer shell is provided with two hanging ears.

[0010] Preferably, the first set of loops is set to twelve groups, and the number of the second set of loops is the same as that of the first set of loops.

[0011] Preferably, the two ends of the damper are connected to the FPSO body and the annular sleeve respectively via the first lug and the second lug.

[0012] Preferably, the damper includes an outer casing and a push rod disposed at one end of the outer casing. The bottom of the outer casing is hinged to the first lug by a bolt one, and the top of the push rod is hinged to the second lug by a bolt two.

[0013] Preferably, a hydraulic chamber and a lubrication chamber are sequentially arranged inside the outer shell. The push rod passes through the lubrication chamber and the hydraulic chamber sequentially along the geometric central axis of the outer shell. A piston is connected to the end of the push rod inside the hydraulic chamber, and the piston is slidably disposed inside the hydraulic chamber.

[0014] Preferably, the piston is provided with a plurality of through holes, a damping spring is provided at one end of the piston, and sealing gaskets are provided at both ends of the lubrication cavity, and the sealing gaskets are all sleeved on the push rod.

[0015] Therefore, the present invention employs the above-described tuned mass damping device for a cylindrical FPSO, which has the following beneficial effects:

[0016] (1) By using the principle of resonance, the energy of vertical motion is absorbed by an additional tuned mass damping device, thereby reducing the vertical disturbance force of the FPSO body. The device can also adjust the system mass by ballast water and adjust the natural frequency of the system according to the wave period to specifically absorb wave frequency energy and slow down the vertical motion of the FPSO body.

[0017] (2) This device can increase the waterline width of the overall structure, thereby further suppressing the swaying motion of the FPSO body; each compartment can further increase the oil storage capacity of the FPSO.

[0018] (3) This device is detachable from the FPSO main body and can be added to an existing cylindrical FPSO platform without redesigning the main body of the FPSO platform.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a tuned mass damping device for a cylindrical FPSO according to an embodiment of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of the annular sleeve according to an embodiment of the present invention;

[0022] Figure 3 This is a top view of the annular sleeve according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the connection of the damper according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the damper structure according to an embodiment of the present invention;

[0025] Figure Labels

[0026] 1. FPSO main body; 1-1. Platform moon pool; 1-2. Conical heave plate; 1-3. Lug 1; 1-3B. Bolt 1; 2. Annular sleeve; 2-1A. Inner outer shell; 2-1B. Upper outer shell; 2-1C. Outer outer shell; 2-1D. Bottom outer shell; 2-3. Main bulkhead; 2-4. Transverse heave bulkhead; 2-5. Longitudinal heave bulkhead; 2-6. Water permeable hole; 2-7. Ballast pump; 2-8. Lug 2; 2-8B. Bolt 2; 3. Damper; 3-1. Outer shell cylinder; 3-1A. Hydraulic chamber; 3-1B. Lubrication chamber; 3-2. Push rod; 3-3. Sealing gasket; 3-4. Vibration damping spring; 3-5. Piston. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] Example:

[0030] like Figure 1-5 As shown, the present invention provides a tuned mass damping device for a cylindrical FPSO, comprising an FPSO body 1, an annular sleeve 2 and a damper 3, wherein the damper 3 is disposed between the FPSO body 1 and the annular sleeve 2.

[0031] The FPSO main body 1 includes a platform moon pool 1-1, a conical heave plate 1-2, and lugs 1-3. The conical heave plate 1-2 is located below the platform moon pool 1-1, and the lugs 1-3 are located above the conical heave plate 1-2. In this embodiment, twelve sets of dampers 3 are evenly arranged around the FPSO main body 1, so twelve sets of lugs 1-3 are also correspondingly arranged on the conical heave plate 1-2, and twelve sets of lugs 2-8 are correspondingly arranged on the annular sleeve 2.

[0032] In this embodiment, the annular sleeve 2 is located outside the FPSO body 1, and the inner side of the annular sleeve 2 has a corresponding number of lugs 2-8. The two ends of the damper 3 are connected to the FPSO body 1 and the annular sleeve 2 respectively via lug 1-3 and lug 2-8, using a free hinge connection. This allows the annular sleeve 2 to be arranged concentrically with the FPSO body 1, and the annular sleeve 2 to move vertically along its central axis. Since the damper 3 is connected by bolts at each point using a free hinge connection, only one rotational degree of freedom is retained. Therefore, when the number of dampers 3 is greater than two, the annular sleeve 2 will not be able to rotate relative to the FPSO body 1. Increasing the number of dampers 3 strengthens the restriction on the rotational degree of freedom of the annular sleeve 2.

[0033] like Figure 2As shown, the annular sleeve 2 includes an inner outer shell 2-1A, an upper outer shell 2-1B, an outer outer shell 2-1C, and a bottom outer shell 2-1D. The upper outer shell 2-1B and the bottom outer shell 2-1D are respectively located at the top and bottom of the inner outer shell 2-1A. The inner outer shell 2-1A and the outer outer shell 2-1C are located between the upper outer shell 2-1B and the bottom outer shell 2-1D. The inner outer shell 2-1A, the upper outer shell 2-1B, the outer outer shell 2-1C, and the bottom outer shell 2-1D form a bottom watertight hollow annular structure. The internal space of the annular sleeve 2 is divided by twelve vertically arranged main bulkheads 2-3 to form twelve independent compartments. Each compartment is equipped with three vertically arranged transverse control bulkheads 2-4 and one vertically arranged longitudinal control bulkhead 2-5. Water-permeable holes 2-6 are provided at the bottom and middle of the transverse and longitudinal swaying bulkheads 2-4 and 2-5, respectively. Their function is to reduce the sloshing effect of ballast water within the annular sleeve 2 during its movement, thereby enhancing the hydrodynamic performance of the annular sleeve 2. A ballast pump 2-7 is located at the bottom of the compartment, serving as the sole pathway for seawater exchange between each compartment and the surrounding water. The ballast pump 2-7 is closed during normal operation. When the device needs to change the target frequency based on environmental conditions, the ballast pump 2-7 is activated to alter the volume of ballast water within the compartment, thus regulating the overall mass of the annular sleeve 2 and changing the device's natural frequency. The ballast pump 2-7 is deactivated when the target frequency is reached. Due to the relative independence of the compartments within the annular sleeve 2, some compartments can be selected as oil storage tanks, while the remaining compartments retain their ballast regulation capabilities, achieving the same natural frequency regulation function. Lugs 2-8 are arranged on the inner outer shell 2-1A according to their connection positions; such as... Figure 3 As shown, the main partition 2-3 is positioned radially with the second lug 2-8, and the main partition 2-3 provides local reinforcement to the position of the second lug 2-8. Based on the number of second lugs 2-8 (n), the spacing α of the main partition 2-3 can be determined to be 360° / n.

[0034] In this embodiment, the damper 3 is connected as follows: Figure 4 As shown, the damper 3 includes an outer shell 3-1 and a push rod 3-2 disposed at one end of the outer shell. The outer shell 3-1 is connected to the lug 1-3 by bolt 1-3B to form a free hinge connection; the push rod 3-2 is connected to the lug 2-8 by bolt 2-8B to form a free hinge connection.

[0035] In this embodiment, the specific structural composition of the damper 3 is as follows: Figure 5As shown. The outer casing 3-1 contains two chambers: a hydraulic chamber 3-1A and a lubrication chamber 3-1B. A push rod 3-2 passes sequentially through the lubrication chamber 3-1B and the hydraulic chamber 3-1A along the geometric axis of the outer casing 3-1. A piston 3-5 is connected to the end of the push rod 3-2 within the hydraulic chamber 3-1A. The piston 3-5 can only slide along its axis within the hydraulic chamber 3-1A. Several through holes 3-6 are provided on the piston 3-5 to ensure that when the piston 3-5 reciprocates within the hydraulic chamber 3-1A, the liquid in the chambers on both sides of the piston 3-5 can only flow through the holes 3-6, thus achieving a damping effect. A damping spring 3-4 is provided at one end of the piston 3-5 and is connected to the inner wall of the hydraulic chamber 3-1A through the damping spring 3-4. Sealing gaskets 3-3 are located at both ends of the lubrication chamber 3-1B and are respectively fitted onto the push rod 3-2, serving to prevent air from entering the chamber and liquid from flowing out of the chamber.

[0036] Working Principle: After damper 3 is installed, the damping ratio of the device cannot be changed. Therefore, the total weight of the tuned mass damping device needs to be adjusted to the required mass at the target frequency using ballast pump 2-7. The system's center of gravity is also adjusted to the axis using ballast pump 2-7. After completion, ballast pump 2-7 is turned off, and the annular sleeve 2 is allowed to reach equilibrium. Based on the principle of resonant tuning, the heave suppression requirement is highest when the wave frequency matches the heave frequency of the FPSO body 1. The target tuning frequency can be determined to be within the range of 0.9-1.1 times the natural frequency of the FPSO body 1. The restoring force stiffness of the water body directly on the device is calculated using the water surface area of ​​the annular sleeve 2. The total weight of the annular sleeve 2 after ballasting is determined to be within the range of 0.05-0.1 times the mass of the FPSO body. Considering a damping ratio of 0.05-0.2, a heave suppression effect of 30-60% is expected. When the device encounters waves at the target frequency, the annular sleeve 2 only generates heaving motion relative to the FPSO body 1. Due to the presence of the damper 3, the annular sleeve 2, due to its heaving motion, generates a damping force on the FPSO body 1 in the vertical direction. This force has the same frequency as the wave force but a different phase and amplitude. Therefore, by properly designing and arranging the damper 3, the effect of the vertical wave force can be offset to a certain extent, thereby mitigating the FPSO's heaving motion. At the same time, the annular sleeve 2 increases the overall waterline area of ​​the structure, indirectly enhancing the stability of the FPSO body 1 and reducing its response in the degree of freedom of swaying.

[0037] Therefore, the present invention employs the above-mentioned tuned mass damping device for cylindrical FPSO, which can adjust the overall mass of the annular sleeve by ballast water, thereby changing the system's natural frequency to accurately correspond to the wave frequency in the environmental load.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A tuned mass damping device for a cylindrical FPSO, characterized in that: The FPSO includes a main body, an annular sleeve, and a damper. The annular sleeve is disposed outside the FPSO main body, and the damper is disposed between the FPSO main body and the annular sleeve. The FPSO main body includes a platform moon pool, a conical heave plate, and a first hanging lug. The conical heave plate is disposed below the platform moon pool, and the first hanging lug is disposed above the conical heave plate. The internal space of the annular sleeve is divided by twelve vertically arranged main partitions to form twelve independent compartments. Each compartment is equipped with three vertically arranged transverse control bulkheads and one vertically arranged longitudinal control bulkhead. The annular sleeve is provided with two hanging lugs; The damper includes an outer shell and a push rod disposed at one end of the outer shell. The bottom of the outer shell is hinged to the first lug by a bolt one; the top of the push rod is hinged to the second lug by a bolt two. The outer shell has a hydraulic chamber and a lubrication chamber arranged sequentially inside. The push rod passes through the lubrication chamber and the hydraulic chamber sequentially along the geometric central axis of the outer shell. The end of the push rod in the hydraulic chamber is connected to a piston, which is slidably disposed in the hydraulic chamber.

2. The tuned mass damping device for a cylindrical FPSO according to claim 1, characterized in that: The annular sleeve includes an inner outer shell, an upper outer shell, an outer outer shell, and a bottom outer shell. The upper outer shell and the bottom outer shell are respectively disposed at the top and bottom ends of the inner outer shell, and the inner outer shell and the outer outer shell are disposed between the upper outer shell and the bottom outer shell.

3. A tuned mass damping device for a cylindrical FPSO according to claim 1, characterized in that: The transverse and longitudinal swaying bulkheads are respectively provided with water-permeable holes at the bottom and middle, and each of the compartments is equipped with a ballast pump at the bottom.

4. A tuned mass damping device for a cylindrical FPSO according to claim 3, characterized in that: The first type of ear loop is set to twelve groups, and the second type of ear loop has the same number as the first type of ear loop.

5. A tuned mass damping device for a cylindrical FPSO according to claim 4, characterized in that: The two ends of the damper are connected to the FPSO body and the annular sleeve respectively through the first and second lugs.

6. A tuned mass damping device for a cylindrical FPSO according to claim 1, characterized in that: The piston has several through holes, a damping spring is provided at one end of the piston, and sealing gaskets are provided at both ends of the lubrication cavity, with the sealing gaskets all fitted onto the push rod.

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