Tuning heave plate semi-submersible platform containing inerter and structural parameter optimization design method thereof

Abstract

The invention discloses a tuning heave plate semi-submersible platform containing an inerter and a structural parameter optimization design method of the tuning heave plate semi-submersible platform, and belongs to the field of floating wind turbine platform vibration suppression. Comprising a semi-submersible platform, a stand column, a spring-damping-inerter structure and a heaving plate. The heaving plate and the semi-submersible platform are oppositely installed in an up-down parallel mode through the stand column and the spring-damping-inerter structure, the upper end of the stand column is fixedly connected with the bottom of the semi-submersible platform, the lower end of the stand column is fixedly connected with the upper end of the spring-damping-inerter structure, and the lower end of the spring-damping-inerter structure is fixedly connected with the heaving plate. The heaving plate can move up and down relative to the semi-submersible platform through a spring-damping-inerter structure. The semi-submersible type wind turbine platform has the advantages of being high in bearing capacity and good in heaving restraining effect, unsteady heaving borne by the semi-submersible type wind turbine platform in different sea conditions can be reduced, and therefore the service life and performance of the semi-submersible type wind turbine platform are guaranteed.

Description

Technical Field

[0001] The invention relates to a tuned heave plate semi-submersible platform containing an inertia container and a structural parameter optimization design method thereof, and belongs to the field of vibration suppression of floating wind turbine platforms. Background Art

[0002] Offshore wind energy reserves are abundant. For deep seas, floating installation of offshore wind turbines is more suitable. Common floating platforms for offshore wind turbines include column type, tension leg type, barge type and semi-submersible type. Semi-submersible platforms are widely used due to their wide applicable water depth range, large waterline area and large payload capacity. However, semi-submersible platforms may produce large heave motion due to shallow draft and large pontoon, which not only affects power generation efficiency but also endangers structural safety. Therefore, it is of great significance to take effective vibration suppression measures to control vibration within an acceptable range.

[0003] In order to reduce the harm caused by vibration, scholars have adopted a variety of means or measures to control harmful vibrations, among which the tuned heave plate is an effective and very important vibration control technology. At present, an obvious disadvantage of the traditional tuned heave plate to control vibration is that its control effectiveness depends largely on the percentage of auxiliary mass. For semi-submersible platforms with large main structure mass, the large auxiliary structure will not only increase the cost, but also increase the technical difficulty. Therefore, it is necessary to innovate and improve the traditional tuned heave plate. Summary of the invention

[0004] The present invention provides a tuned heave plate semi-submersible platform including an inertia container and a structural parameter optimization design method thereof. By combining an open fluid inertia container and a spring damping vibration isolation structure, a tuned heave plate semi-submersible platform including an open fluid inertia container is constructed. The semi-submersible platform has the characteristics of high bearing capacity and can reduce the unsteady heave motion of the semi-submersible platform, thereby ensuring the service life and performance of the equipment. A specific structural parameter optimization design method is further provided.

[0005] The technical solution adopted by the present invention is: a tuned heave plate semi-submersible wind turbine platform containing an inertia vessel, comprising a semi-submersible platform 1, a column 2, a spring-damper-inertia vessel structure 3, and a heave plate 4; the heave plate 4 and the semi-submersible platform 1 are installed in parallel and opposite to each other through the column 2 and the spring-damper-inertia vessel structure 3, the upper end of the column 2 is fixedly connected to the bottom of the semi-submersible platform 1, and the lower end is fixedly connected to the upper end of the spring-damper-inertia vessel structure 3, the lower end of the spring-damper-inertia vessel structure 3 is fixedly connected to the heave plate 4, and the heave plate 4 can move up and down relative to the semi-submersible platform 1 through the spring-damper-inertia vessel structure 3.

[0006] Specifically, the spring-damping-inertia container structure 3 includes a spring-damping-inertia container structure connecting flange 5, an upper telescopic structure 6, a lower telescopic structure 11, a spring damping vibration isolation structure 7, an open fluid inertia container 10, and a spring structure 14; the upper end of the spring-damping-inertia container structure connecting flange 5 is fixedly connected to the bottom of the column 2, and the lower end is fixedly connected to the top of the upper telescopic structure 6; the lower telescopic structure 11 is sleeved on the outside of the upper telescopic structure 6; the top of the spring damping vibration isolation structure 7 is fixedly connected to the inner wall of the top of the upper telescopic structure 6, and the bottom is fixedly connected to the top of the open fluid inertia container 10; the bottom of the open fluid inertia container 10 is fixedly connected to the heave plate 4; the top of the spring structure 14 is fixedly connected to the inner wall of the top of the upper telescopic structure 6, and the bottom is fixedly connected to the heave plate 4; the spring damping vibration isolation structure 7 and the open fluid inertia container 10 are connected in series, and then the whole is connected in parallel with the spring structure 14.

[0007] Specifically, the spring damping vibration isolation structure 7 includes a connecting member 701, a spring 702, a damper 703, a spring seat 704 and a spring damping vibration isolation structure mounting seat 705; the upper end of the connecting member 701 is a fixed mounting seat, and the lower end is cast with a spring baffle, the fixed mounting seat at the upper end of the connecting member 701 is connected to the upper telescopic structure 6, the piston rod of the damper 703 passes through the hole in the center of the spring baffle and is connected to the bottom of the connecting member 701, the spring 702 is vertically sleeved on the outside of the damper 703, and is connected in parallel with the damper 703, a spring tray 704 is fixed to the outer side of the lower part of the damper 703, the spring 702 is installed between the spring baffle and the spring tray 704, and the bottom of the damper 703 is fixedly connected to the spring damping vibration isolation structure mounting seat 705.

[0008] Specifically, the open fluid inertial container 10 includes an inertial container upper end mounting seat 1001, a spiral tube support tube 1002, a spiral tube 1004, a pull rod 1005, a hydraulic cylinder 1006, an inertial container lower end mounting seat 1007 and a straight pipe joint 1008; the hydraulic cylinder 1006 is installed below the inertial container upper end mounting seat 1001, the top of the inertial container upper end mounting seat 1001 is fixedly connected to the spring damping vibration isolation structure 7, and the bottom is fixedly connected to the piston rod end in the hydraulic cylinder 1006, the pull rod 1005 passes through the flanges at the upper and lower ends of the hydraulic cylinder 1006, and its bottom is fixedly connected to the inertial container lower end mounting seat 1007, and the top is fixedly connected to the upper end of the hydraulic cylinder 1006. The end flanges are fixedly connected, the pull rod 1005 and the hydraulic cylinder 1006 are located in the spiral tube support tube 1002, the upper and lower spiral tubes 1004 are wound around the spiral tube support tube 1002, and the upper and lower ends of the hydraulic cylinder 1006 are connected with straight pipe joints 1008. One end of the upper spiral tube 1004 is connected to the upper straight pipe joint 1008, and the other end passes through the opening on the lower telescopic structure 11 and directly contacts the seawater. One end of the lower spiral tube 1004 is connected to the lower straight pipe joint 1008, and the other end passes through the opening on the lower telescopic structure 11 and directly contacts the seawater. The bottom of the lower end mounting seat 1007 of the inertial container is fixedly connected to the heave plate 4.

[0009] Preferably, the contact position between the opening of the lower telescopic structure 11 and the spiral tube 1004 is sealed, and a filter screen is provided at the outlet of the spiral tube 1004 in contact with seawater.

[0010] Specifically, the spring structure 14 includes a spring structure upper end mounting seat 1401, a connecting column 1402, a guide rod 1403, a spring baffle 1404, a compression spring 1405, and a spring structure bottom mounting seat 1406 cast with a cylindrical boss; the top of the spring structure upper end mounting seat 1401 is fixedly connected to the top of the upper telescopic structure 6, the upper end of the connecting rod 1402 is fixedly connected to the spring structure upper end mounting seat 1401, and the lower end is fixedly connected to the spring baffle 1404, the compression spring 1405 is installed between the spring baffle 1404 and the spring structure bottom mounting seat 1406, and its position is limited by these two parts, the bottom of the guide rod 1403 is fixed on the cylindrical boss on the spring structure bottom mounting seat 1406, and the upper end passes through the spring baffle 1404 and is fixed by the nut II 13, and the spring structure bottom mounting seat 1406 is fixedly connected to the vertical swing plate 4.

[0011] Preferably, the top of the spring structure upper mounting seat 1401 is connected to the top of the upper telescopic structure 6 by bolt II12, the spring damping vibration isolation structure mounting seat 705 is fixedly connected to the inertial container upper mounting seat 1001 by bolt I8 and nut I9, and the top of the pull rod 1005 is fixedly connected to the upper flange of the hydraulic cylinder 1006 by a pull rod nut 1003.

[0012] Preferably, the semi-submersible platform 1, the columns 2, the upper telescopic structure 6, the lower telescopic structure 11 and the heave plate 4 are made of a material with a density of 7850 kg / m 3 of steel.

[0013] A method for optimizing the structural parameters of a tuned heave plate semi-submersible platform with an inertia container, using the tuned heave plate semi-submersible platform with an open fluid inertia container as claimed in claim 6, and specifically comprising the following steps:

[0014] Step 1: The total mass of the semi-submersible platform 1 and the heave plate 4 is M 1 and M 2 When waves act on the semi-submersible platform 1 and the heave plate 4, the semi-submersible platform 1 and the heave plate 4 deviate from the equilibrium position, the spring 702 and the damper 703 in the spring damping vibration isolation structure 7 are compressed or restored, and the piston rod of the hydraulic cylinder 1006 in the open fluid inertia container 10 is pushed, and the piston rod moves relative to the hydraulic cylinder 1006 so that the fluid flows along the spiral tube 1004, and the spring structure 14 connected in parallel with the spring damping vibration isolation structure 7 and the open fluid inertia container 10 is compressed or restored, and the tuned heave plate 4 starts to work;

[0015] Step 2: Perform dynamic analysis on the semi-submersible platform 1, establish a dynamic model of the system, and derive the heave motion transfer function of the model;

[0016] Step 3: Taking the minimum root mean square value of the heave motion of the semi-submersible platform 1 as the optimization target, the structural parameters of the semi-submersible platform 1 are optimized by using fmincon according to different wave conditions;

[0017] Step 4: Taking the root mean square value of the heave motion of the semi-submersible platform 1 as an evaluation index of the vibration suppression performance, the heave motion suppression performance of the semi-submersible platform containing the inertia container is analyzed.

[0018] Specifically, the structural parameters include the stiffness of the spring 702 and the compression spring 1405 , the damping coefficient of the damper 703 , and the inertia coefficient of the open fluid inertia container 10 .

[0019] The beneficial effects of the present invention are:

[0020] 1. The present invention is based on the tuned mass damper damping principle. An inertia vessel is added to the tuned heave plate semi-submersible platform to form a tuned heave plate inertia vessel system semi-submersible platform, and a control device based on an inertia vessel is realized. The heave plate system not only provides additional mass for the semi-submersible platform underwater, but also provides viscous damping, thereby effectively improving the heave suppression performance of the semi-submersible platform. By changing the spring damping connection between the semi-submersible platform and the heave plate to a spring-damper-inertia vessel structure connection, the effectiveness of the heave motion suppression performance of the semi-submersible platform is further improved. The combination of the inertia vessel and the spring damping vibration isolation structure enables the same level of vibration suppression of the semi-submersible platform to be achieved by using a device with a smaller (physical) mass. In addition, the introduction of the inertia vessel enables the tuned heave plate semi-submersible platform to effectively suppress the amplitude of the resonance peak.

[0021] 2. The present invention introduces an open fluid inertia container, and cooperates with traditional springs and damping vibration reduction elements to build a tuned heave plate semi-submersible platform. The addition of the inertia container can better improve the heave suppression performance of the semi-submersible platform and maintain the stability of the structure, and the same level of vibration suppression requires a smaller auxiliary mass. In addition, the open fluid inertia container can provide a large virtual auxiliary mass to achieve the advantage of adjustable large inertia when its own volume and actual mass are small, which can coordinate the contradiction between the auxiliary mass and the weight reduction of the entire semi-submersible platform.

[0022] 3. The present invention can adjust the vibration suppression range and bearing capacity of the semi-submersible platform of the tuned heave plate inertia system by changing structural parameters such as the stiffness of the spring, the damping coefficient of the damper, and the inertia coefficient of the open fluid inertia container. It can be applied to different sea conditions and the structure can be flexibly adjusted and optimized according to the weight and installation space of the semi-submersible platform.

[0023] 4. The present invention provides a semi-submersible platform with a tuned heave plate containing an inertia container. The semi-submersible platform, columns, upper and lower telescopic structures, and heave plates are made of a density of 7850kg / m 3 The steel is used for the rest of the structure, and the commonly used metal materials are used. Most of the parts are standard parts, with low cost, simple structure, convenient processing, manufacturing and installation, strong practicality and replaceability, and good engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall structure of an optional specific embodiment of the present invention;

[0025] Figure 2 It is a schematic diagram of the spring-damper-inertia container structure of the present invention;

[0026] Figure 3It is a schematic diagram of a semi-submersible platform of a tuned heave plate inertia system of the present invention;

[0027] Figure 4 It is a schematic diagram of the spring-damper-inertia container combination structure of the present invention;

[0028] Figure 5 It is a schematic diagram of the spring damping vibration isolation structure of the present invention;

[0029] Figure 6 It is a schematic structural diagram of an open fluid inertia container of the present invention;

[0030] Figure 7 It is a schematic diagram of the spring structure of the present invention;

[0031] Figure 8 It is a comparison chart of the heave response spectrum of the present invention and a semi-submersible platform without an inertia container.

[0032] The numbers in the figure are: 1-semi-submersible platform, 2-column, 3-spring-damping-inertial container structure, 4-heave plate, 5-spring-damping-inertial container structure connecting flange, 6-upper telescopic structure, 7-spring damping vibration isolation structure, 701-connecting piece, 702-spring, 703-damper, 704-spring seat, 705-spring damping vibration isolation structure mounting seat, 8-bolt I, 9-nut I, 10-open fluid inertial container, 1001-inertial container upper end mounting seat, 1002 -Spiral tube support tube, 1003-pull rod nut, 1004-spiral tube, 1005-pull rod, 1006-hydraulic cylinder, 1007-inertial container lower end mounting seat, 1008-straight pipe joint, 11-lower telescopic structure, 12-bolt II, 13-nut II, 14-spring structure, 1401-spring structure upper end mounting seat, 1402-connecting column, 1403-guide rod, 1404-spring baffle, 1405-compression spring, 1406-spring structure bottom mounting seat. DETAILED DESCRIPTION

[0033] The invention will be further described below in conjunction with the accompanying drawings and embodiments, but the content of the invention is not limited to the scope of the embodiments.

[0034] Example 1: Figure 1-8As shown, according to one aspect of an embodiment of the present invention, a tuned heave plate semi-submersible platform including an inertia vessel is provided, comprising a semi-submersible platform 1, a column 2, a spring-damper-inertia vessel structure 3, and a heave plate 4; a set of tuned heave plate inertia vessel systems are coaxially installed on the bottom surfaces of three buoys of the semi-submersible platform 1, wherein the heave plate 4 and the semi-submersible platform 1 are installed in parallel and opposite to each other up and down through the column 2 and the spring-damper-inertia vessel structure 3, the upper end of the column 2 is fixedly connected to the bottom of the semi-submersible platform 1, and the lower end is fixedly connected to the upper end of the spring-damper-inertia vessel structure 3, the lower end of the spring-damper-inertia vessel structure 3 is fixedly connected to the heave plate 4, and the heave plate 4 can move up and down relative to the semi-submersible platform 1 through the spring-damper-inertia vessel structure 3.

[0035] Furthermore, the spring-damping-inertia container structure 3 includes a spring-damping-inertia container structure connecting flange 5, an upper telescopic structure 6, a lower telescopic structure 11, a spring damping vibration isolation structure 7, bolts I 8, nuts I 9, an open fluid inertia container 10, bolts II 12, nuts II 13, and a spring structure 14. Figure 1 Three heave plates 4 are shown, each of which is connected to the semi-submersible platform 1 through three groups of columns 2 and spring-damping-inertia container structures 3 evenly distributed about the center line of the heave plates 4. Specifically, the upper end of the spring-damping-inertia container structure connection flange 5 is fixedly connected to the bottom of the column 2, and the lower end is fixedly connected to the top of the upper telescopic structure 6. The lower telescopic structure 11 is sleeved on the outside of the upper telescopic structure 6. The top of the spring damping vibration isolation structure 7 is fixedly connected to the inner wall of the top of the upper telescopic structure 6, and the bottom is fixedly connected to the top of the open fluid inertia container 10. The bottom of the open fluid inertia container 10 is fixedly connected to the heave plate 4. The top of the spring structure 14 is fixedly connected to the inner wall of the top of the upper telescopic structure 6, and the bottom is fixedly connected to the heave plate 4. The spring damping vibration isolation structure 7 and the open fluid inertia container 10 are connected in series, and then the whole is connected in parallel with the spring structure 14.

[0036] Furthermore, the spring damping vibration isolation structure 7 includes a connector 701, a spring 702, a damper 703, a spring seat 704 and a spring damping vibration isolation structure mounting seat 705. The upper end of the connector 701 is a fixed mounting seat, through holes are provided at the four corners of the fixed mounting seat at the upper end of the connector 701, four threaded holes are drilled at corresponding positions on the inner side of the top of the upper telescopic structure 6, and the fixed mounting seat at the upper end of the connector 701 is connected to the upper telescopic structure 6 by bolts. A spring stopper is cast at the lower end of the connector 701. The piston rod of the damper 703 passes through the hole in the center of the spring stopper and is connected to the bottom of the connector 701. The spring 702 is vertically sleeved outside the damper 703 and is connected in parallel with the damper. A spring tray 704 is fixed to the outer side of the lower part of the damper 703. The spring 702 is installed between the spring stopper and the spring tray 704. Six countersunk holes with equal spacing are opened in the middle part of the spring damping vibration isolation structure mounting seat 705, which is connected to the bottom of the damper 703 with bolts. The spring damping vibration isolation structure 7 is fixedly connected to the upper mounting seat 1001 of the open fluid inertial container 10 through the through holes at the four corners of the bottom spring damping vibration isolation structure mounting seat 705 with bolts Ⅰ8 and nuts Ⅰ9. The hydraulic cylinder 1006 in the open fluid inertial container 10 is bolted to the heave plate 4 through the lower mounting seat 1007 of the inertial container.

[0037] Furthermore, the open fluid inertia container 10 includes an inertia container upper end mounting seat 1001, a spiral tube support tube 1002, a tie rod nut 1003, a spiral tube 1004, a tie rod 1005, a hydraulic cylinder 1006, an inertia container lower end mounting seat 1007 and a straight pipe joint 1008; the inertia container lower end mounting seat 1007 and the hydraulic cylinder 1006 are connected by four groups of tie rods 1005 and tie rod nuts 1003, the entire hydraulic cylinder is fixedly connected to the heave plate 4 by bolts by the inertia container lower end mounting seat 1007, the piston rod end in the hydraulic cylinder 1006 is threadedly connected to the bottom of the inertia container upper end mounting seat 1001, the straight pipe joint 1008 is threadedly connected to the hydraulic cylinder 1006, and the two The spiral tube 1004 is wound around the spiral tube support tube 1002, and the upper and lower ends of the hydraulic cylinder 1006 are connected with straight pipe joints 1008. One end of the upper spiral tube 1004 is connected to the upper straight pipe joint 1008, and the other end passes through the opening on the lower telescopic structure 11 to directly contact with seawater. One end of the lower spiral tube 1004 is connected to the lower straight pipe joint 1008, and the other end passes through the opening on the lower telescopic structure 11 to directly contact with seawater. The bottom of the lower end mounting seat 1007 of the inertial container is fixedly connected to the heave plate 4, the contact position between the opening of the lower telescopic structure 11 and the spiral tube 1004 is sealed, and a filter is provided at the outlet where the spiral tube 1004 contacts with seawater.

[0038] Furthermore, the spring structure 14 includes a spring structure upper end mounting seat 1401, a connecting column 1402, a guide rod 1403, a spring baffle 1404, a compression spring 1405, and a spring structure bottom mounting seat 1406 cast with a cylindrical boss; the compression spring 1405 is connected to the upper telescopic structure 6 through the spring structure upper end mounting seat 1401 by a bolt II 12, the connecting column 1402 is connected to the spring structure upper end mounting seat 1401 by a thread, and the other end of the connecting column 1402 passes through the spring baffle 1404 and is fixed by a locking nut. The compression spring 1405 is installed between the spring baffle 1404 and the bottom mounting seat 1406 of the spring structure, and its position is limited by these two parts. The cylindrical boss on the bottom mounting seat 1406 of the spring structure is connected to the guide rod 1403 through a thread. The cylindrical boss prevents the compression spring 1405 from deviating from the vertical direction. The guide rod 1403 guides the compression spring 1405 to be compressed and restored along the vertical direction. The nut II 13 prevents the guide rod 1403 from detaching from the cylindrical boss. The spring structure 14 is connected to the vertical swing plate 4 by bolts through the bottom mounting seat 1406 of the spring structure.

[0039] The working principle of the present invention is as follows: the device of the present invention is placed in the sea waves, the draft of the semi-submersible platform 1 is 20m, the column 2, the spring-damper-inertia container structure 3 and the heave plate 4 are completely immersed in the sea water, and the initial draft of the heave plate 4 is 60m. When the wave acts on the semi-submersible platform 1 and the heave plate 4, the semi-submersible platform 1 and the heave plate 4 move up and down, and the spring 702, the damper 703 and the open fluid inertia container 10 are compressed or stretched. The shape change of the spring 702 effectively absorbs and reduces the vibration, and the shape change of the damper 703 consumes The energy of the dissipation device is obtained by tuning the natural frequency of the heave plate 4 to the vicinity of the spectrum peak frequency of the wave under the corresponding sea conditions, so that the movement amplitude of the heave plate 4 is amplified. The entire heave plate system can provide a larger inertial force and viscous damping force for the semi-submersible platform 1, thereby reducing the vibration of the semi-submersible platform 1 when the excitation amplitude is large, especially effectively suppressing the amplitude of the resonance peak. In addition, the open fluid inertia container 10 has the dynamic characteristics of a large inertia body that can be adjusted by amplifying a smaller self-mass, and the generated inertial force can offset a certain elastic force and weaken the transmission of vibration.

[0040] By applying the above technical solution, it can be known that the present invention uses the spring-damper-inertia container structure 3 as the connection structure between the semi-submersible platform 1 and the heave plate 4 to ensure that the semi-submersible platform 1 has better bearing capacity and stability during operation. By vertically installing the spring damping vibration isolation structure 7 inside the upper telescopic structure 6 and the lower telescopic structure 11, the open fluid inertia container 10 is vertically installed in the lower telescopic structure 11 and connected in series with the spring damping vibration isolation structure 7, and a spring structure 14 is connected in parallel next to the spring-damper-inertia container structure 3 to prevent the open fluid inertia container 10 from being broken down. The open fluid inertia container 10 is used as an anti-resonance element in the semi-submersible platform 1. The inertial force generated during the movement can offset a part of the elastic force and weaken the energy transmitted along the vibration path. The introduction of the open fluid inertia container 10 can significantly improve the heave suppression performance of the semi-submersible platform 1 and improve the stability of the center of mass of the entire semi-submersible platform 1 during vibration.

[0041] According to another aspect of an embodiment of the present invention, a method for optimizing the structural parameters of a semi-submersible platform with a tuned heave plate including an inertia container is provided, comprising:

[0042] Step 1: The total mass of the semi-submersible platform 1 and the heave plate 4 is M 1 and M 2 When waves act on the semi-submersible platform 1 and the heave plate 4, the semi-submersible platform 1 and the heave plate 4 deviate from the equilibrium position, the spring 702 and the damper 703 in the spring damping vibration isolation structure 7 are compressed or restored, and the piston rod of the open fluid inertial container 10 is pushed, and the piston rod moves relative to the hydraulic cylinder 1006 to make the fluid flow along the spiral tube 1004, and the spring structure 14 connected in parallel with the spring damping vibration isolation structure 7 and the open fluid inertial container 10 is compressed or restored, and the tuned heave plate 4 starts to work;

[0043] Step 2: Perform dynamic analysis on the semi-submersible platform 1, establish a dynamic model of the system, and derive the heave motion transfer function of the model;

[0044] Step 3: Taking the minimum root mean square value of the heave motion of the semi-submersible platform 1 as the optimization target, the structural parameters of the semi-submersible platform 1 are optimized by using fmincon according to different wave conditions;

[0045] Step 4: Taking the root mean square value of the heave motion of the semi-submersible platform 1 as an evaluation index of the vibration suppression performance, the heave motion suppression performance of the semi-submersible platform containing the inertia container is analyzed.

[0046] The structural parameters include the stiffness of the spring 702 and the compression spring 1405 , the damping coefficient of the damper 703 , and the inertia coefficient of the open fluid inertia container 10 .

[0047] In this embodiment, a dynamic analysis is performed on a semi-submersible platform with a tuned heave plate inertia system. The structure and parameters of the semi-submersible platform are given by Figure 3 and Figure 4 Given: The total mass of the semi-submersible platform and the heave plate is M 1 and M 2 The excitations of the semi-submersible platform and the heave plate are f 1 (t) and f 2 (t), the hydrostatic recovery stiffness provided by the water around the semi-submersible platform is K 0 , the inherent damping provided by seawater to the semi-submersible platform and the heave plate is C v1 and C v2 , the stiffness of the spring 702 in the spring damping vibration isolation structure is K 3 , the damping coefficient of damping 703 is C 2 The inertia coefficient of the open fluid inertia container 10 is b, and the stiffness of the compression spring 1405 is K 2 ;Depend on Figure 3 and Figure 4 The dynamic expression of the tuned heave plate semi-submersible platform structure with inertia container is:

[0048]

[0049] Among them, z 1 (t) and are the vertical displacement, velocity and acceleration of the semi-submersible platform in the time domain; z 2 (t) and are the vertical displacement, velocity and acceleration of the heave plate in time domain, respectively.

[0050] In formula (1), f 2 ′(t) is the force generated by the spring-damper-inertia container structure 3, and its expression is:

[0051]

[0052] Among them, z b (t) and They are the vertical displacement, velocity and acceleration of the connection point between the internal inertial container and the spring damping vibration isolation structure of the spring-damper-inertial container structure 3 in the time domain.

[0053] The nonlinear damping term in equation (1) can be approximately linearized as follows:

[0054]

[0055] Among them, Z 1is the amplitude of the heave motion of the semi-submersible platform; ω is the wave excitation frequency, in rad / s.

[0056] Based on the undamped Morrison equation, the wave force f acting on the semi-submersible platform is 1 (t) can be expressed as the sum of the wave forces acting on the base column and the outer columns:

[0057]

[0058] Where ρ is the density of seawater, c a1 is the additional mass coefficient of the base column, V p is the reference volume of the base column, c d1 is the resistance coefficient of the base column, A 1 is the vertical projection area of ​​a base column, v z and a z The velocity and acceleration of water particles in the vertical direction when the water depth is z, D 1 is the base column diameter, D c is the diameter of the outer column, j is the number of the base column on the semi-submersible platform, p bj and p tj are the dynamic pressures acting on the bottom and top surfaces of the column respectively.

[0059] The wave force f on the heave plate 2 The expression of (t) is:

[0060]

[0061] Among them, c a2 is the additional mass coefficient of the heave plate, a d4j The water depth is d 4 The vertical wave acceleration at time V R is the reference volume of a heaving plate.

[0062] Equations (1) and (2) can be written in the Laplace domain as:

[0063]

[0064] Among them, C e1 and C e2 are the linearized inherent damping of the semi-submersible platform 1 and the heave plate 4 respectively; f 1 (s) is the force of waves acting on the semi-submersible platform 1 in the frequency domain; f 2 (s) is the force of the wave acting on the heave plate 4 in the frequency domain; Z 1 (s) is the vertical displacement of the semi-submersible platform 1 in the frequency domain; Z 2 (s) is the vertical displacement of the heave plate 4 in the frequency domain. The force generated by the spring-damper-inertia container structure 3 is expressed in the frequency domain as:

[0065] f 2 ′(s)=α 2 (s)[Z 1 (s)-Z 2 (s)] (7)

[0066] in,

[0067]

[0068] Substituting equation (7) into equation (6), we can obtain the heave transfer function of the semi-submersible platform with a tuned heave plate inertia system:

[0069]

[0070] Among them, F 1 (s) and F 2 (s) are the composite amplitudes of the wave forces acting on the semi-submersible platform 1 and the heave plate 4, respectively.

[0071] In order to simplify the above equations, the following dimensionless parameters are defined:

[0072]

[0073] Among them, ω s is the natural frequency of the semi-submersible platform 1, ω 2 is the natural frequency of the tuned heave plate inertia system, ω b is the corner frequency of the tuned heave plate inertia system, ξ 1 is the inherent damping ratio of the semi-submersible platform 1, ξ 2 is the inherent damping ratio of the heave plate 4, ξ 22 is the damping ratio of the tuned heave plate inertia system, μ is the mass ratio of the heave plate 4 to the semi-submersible platform 1, γ 2 is the damping ratio of the tuned heave plate inertia system, δ is the mass ratio of the inertia coefficient of the open fluid inertia container 10 to the heave plate 4, and η is the corner frequency ratio of the tuned heave plate inertia system.

[0074] Based on the dimensionless parameters, equation (9) can be simplified to the following dimensionless form:

[0075]

[0076] in,

[0077]

[0078] Furthermore, fmincon is used to optimize the structural parameters of the semi-submersible platform with a tuned heave plate inertia system for different application scenarios. First, the mass M of the semi-submersible platform is determined. 1 and the mass M of the heave plate2 , wave excitation force f 1 (t) and f 2 (t), hydrostatic recovery stiffness K 0 , then construct the objective function of fimincon, and finally determine the constraints of the structural parameters according to the actual application scenarios.

[0079] When evaluating the heave performance of a semi-submersible platform, the heave motion root mean square value is usually used for quantitative analysis in the frequency domain. The smaller the vertical displacement root mean square value is, the better the heave suppression performance of the semi-submersible platform 1 is. The expression of the heave motion root mean square value of the semi-submersible platform is:

[0080]

[0081] Among them, S Z (ω)=S(ω)|Z 1 (iω) 2 , S(ω) is the power spectral density (PSD) function of the wave load acting on the semi-submersible platform 1, unit: m 2 In this study, the commonly used JONSWAP spectrum is used to represent the power spectral density function of the wave surface elevation, and its expression is:

[0082]

[0083] Among them, H s is the effective wave height, T s is the peak period, ω p is the spectrum peak frequency, ω p =(2π) / T s , γ is the peak raising factor, taking the value corresponding to the average JONSWAP spectrum as 3.3, σ is the peak shape parameter, when ω≤ω p When σ=0.07, when ω>ω p When σ=0.09,

[0084]

[0085] The minimum value problem is:

[0086]

[0087] In the semi-submersible platform of the tuned heave plate inertia system of the present invention, there are four structural parameters to be optimized, namely, the stiffness of the spring in the spring damping vibration isolation structure is K 3 , the damping coefficient of the damper is C 2 The inertia coefficient of the open fluid inertia container is b, and the stiffness of the parallel compression spring is K 2 .

[0088] Under the given conditions, the minimum value of the root mean square value of the heave motion of the semi-submersible platform is selected as the optimization objective. The fmincon function is used to optimize the above four structures within the constraint interval of the structural parameters to solve the structural parameters for the optimal heave suppression.

[0089] Furthermore, the effective wave height H s =13.6m, spectrum peak period T s = 15.1s is taken as an example to illustrate that the total mass of the semi-submersible platform is M 1 =2.76426E+7kg, the total mass of the heave plate is M 2 =2.3039E+6kg, wave force acting on the semi-submersible platform f 1 (t) = -799258*sin(20π / 151*t)+1486085*cos(20π / 151*t), the wave excitation force f acting on the heave plate 2 (t) = -676223*sin(20π / 151*t)+3889*cos(20π / 151*t) and the hydrostatic recovery stiffness is K 0 =3.8265E+6N / m. The structural parameters of the optimal tuned heave plate inertia system obtained through optimization are: K 2 =526610N / m,K 3 =33096N / m, C 2 =2203Ns / m and b=244210kg, substitute into the expression of the heave motion transfer function, and obtain the following through MATLAB plotting: Figure 8 The curve of the heave response spectrum of the semi-submersible platform is shown in the figure, where the tuned heave plate inertia system represents a tuned heave plate semi-submersible platform with an open fluid inertia container, the tuned heave plate represents a tuned heave plate semi-submersible platform without an inertia container, the fixed heave plate represents a semi-submersible platform with a fixedly connected heave plate, and the uncontrolled represents a semi-submersible platform without a heave plate. The smaller the area enclosed by the heave response spectrum curve and the horizontal axis, that is, the smaller the root mean square value of the heave motion of the semi-submersible platform, the better the heave suppression performance of the semi-submersible platform. Figure 8 As shown in the figure, within the range of the natural frequency (0.3-0.4 rad / s) of the semi-submersible platform and the dominant frequency (0.4-0.5 rad / s) of the wave, the peak value of the heave response spectrum of the semi-submersible platform with the tuned heave plate inertia capacity system is smaller than that of the other three semi-submersible platforms, indicating that the tuned heave plate inertia capacity system has a better heave suppression effect in this case. The root mean square values ​​of the heave motion of the semi-submersible platform without control, fixed heave plate, tuned heave plate, and tuned heave plate inertia capacity system are calculated by formula (13): 6.3861m 4 ·s, 4.4162m 4 ·s, 3.5686m 4·s and 3.1802m 4 ·s. Among them, the heave motion root mean square value of the semi-submersible platform with the tuned heave plate inertia capacity system is the smallest, indicating that the tuned heave plate inertia capacity system has the best heave suppression performance.

[0090] It should be noted that if the heave plate of the semi-submersible platform adopts a tuned heave plate, that is, the dynamic expression of the tuned heave plate semi-submersible platform is: where f 1 ′(t) is the force provided by the damper, and its expression is The subsequent process is the same as above.

[0091] The specific implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A tuned heave plate semi-submersible platform with an inertia container, characterized in that: The invention comprises a semi-submersible platform (1), a column (2), a spring-damper-inertia vessel structure (3), and a heave plate (4); the heave plate (4) and the semi-submersible platform (1) are installed in parallel with each other via the column (2) and the spring-damper-inertia vessel structure (3); the upper end of the column (2) is fixedly connected to the bottom of the semi-submersible platform (1), and the lower end is fixedly connected to the upper end of the spring-damper-inertia vessel structure (3); the lower end of the spring-damper-inertia vessel structure (3) is fixedly connected to the heave plate (4); and the heave plate (4) can move up and down relative to the semi-submersible platform (1) via the spring-damper-inertia vessel structure (3).

2. The tuned heave plate semi-submersible platform with inertia container according to claim 1, characterized in that: The spring-damping-inertia container structure (3) comprises a spring-damping-inertia container structure connecting flange (5), an upper telescopic structure (6), a lower telescopic structure (11), a spring damping vibration isolation structure (7), an open fluid inertia container (10), and a spring structure (14); the upper end of the spring-damping-inertia container structure connecting flange (5) is fixedly connected to the bottom of the column (2), and the lower end is fixedly connected to the top of the upper telescopic structure (6); the lower telescopic structure (11) is sleeved outside the upper telescopic structure (6); the top of the spring damping vibration isolation structure (7) is fixedly connected to the inner wall of the top of the upper telescopic structure (6), and the bottom is fixedly connected to the top of the open fluid inertia container (10); the bottom of the open fluid inertia container (10) is fixedly connected to the vertical swing plate (4); the top of the spring structure (14) is fixedly connected to the inner wall of the top of the upper telescopic structure (6), and the bottom is fixedly connected to the vertical swing plate (4); the spring damping vibration isolation structure (7) and the open fluid inertia container (10) are connected in series, and then the whole is connected in parallel with the spring structure (14).

3. The tuned heave plate semi-submersible platform with inertia container according to claim 2 is characterized in that: The spring damping vibration isolation structure (7) comprises a connecting member (701), a spring (702), a damper (703), a spring seat (704) and a spring damping vibration isolation structure mounting seat (705); the upper end of the connecting member (701) is a fixed mounting seat, and the lower end is cast with a spring baffle; the fixed mounting seat at the upper end of the connecting member (701) is connected to the upper telescopic structure (6); the piston rod of the damper (703) passes through the hole in the center of the spring baffle and is connected to the bottom of the connecting member (701); the spring (702) is vertically sleeved on the outside of the damper (703) and is connected in parallel with the damper (703); a spring tray (704) is fixed on the outer side of the lower part of the damper (703); the spring (702) is installed between the spring baffle and the spring tray (704); and the bottom of the damper (703) is fixedly connected to the spring damping vibration isolation structure mounting seat (705).

4. The tuned heave plate semi-submersible platform with inertia container according to claim 3 is characterized in that: The open fluid inertial container (10) comprises an inertial container upper end mounting seat (1001), a spiral tube support tube (1002), a spiral tube (1004), a pull rod (1005), a hydraulic cylinder (1006), an inertial container lower end mounting seat (1007) and a straight pipe joint (1008); the hydraulic cylinder (1006) is mounted below the inertial container upper end mounting seat (1001); the top of the inertial container upper end mounting seat (1001) is fixedly connected to the spring damping vibration isolation structure (7), and the bottom is fixedly connected to the end of the piston rod in the hydraulic cylinder (1006); the pull rod (1005) passes through the flanges at the upper and lower ends of the hydraulic cylinder (1006), and the bottom of the pull rod is fixedly connected to the inertial container lower end mounting seat (1007), and the top is fixedly connected to the upper end of the hydraulic cylinder (1006). The end flanges are fixedly connected, the pull rod (1005) and the hydraulic cylinder (1006) are located in the spiral tube support tube (1002), the upper and lower spiral tubes (1004) are wound around the spiral tube support tube (1002), and the upper and lower ends of the hydraulic cylinder (1006) are connected with straight pipe joints (1008), one end of the upper spiral tube (1004) is connected to the upper straight pipe joint (1008), and the other end passes through the opening on the lower telescopic structure (11) to directly contact the seawater, one end of the lower spiral tube (1004) is connected to the lower straight pipe joint (1008), and the other end passes through the opening on the lower telescopic structure (11) to directly contact the seawater, and the bottom of the lower end mounting seat (1007) of the inertial container is fixedly connected to the vertical swing plate (4).

5. The tuned heave plate semi-submersible platform with inertia container according to claim 4 is characterized in that: The contact position between the opening of the lower telescopic structure (11) and the spiral tube (1004) is sealed, and a filter screen is provided at the outlet of the spiral tube (1004) in contact with seawater.

6. The tuned heave plate semi-submersible platform with inertia container according to claim 4, characterized in that: The spring structure (14) comprises a spring structure upper end mounting seat (1401), a connecting column (1402), a guide rod (1403), a spring baffle (1404), a compression spring (1405), and a spring structure bottom mounting seat (1406) cast with a cylindrical boss; the top of the spring structure upper end mounting seat (1401) is fixedly connected to the top of the upper telescopic structure (6), and the upper end of the connecting rod (1402) is fixedly connected to the spring structure upper end mounting seat (1401). The lower end is fixedly connected to the spring baffle (1404), the compression spring (1405) is installed between the spring baffle (1404) and the spring structure bottom mounting seat (1406), and its position is limited by these two parts, the bottom of the guide rod (1403) is fixed on the cylindrical boss on the spring structure bottom mounting seat (1406), and the upper end passes through the spring baffle (1404) and is fixed by the nut II (13), and the spring structure bottom mounting seat (1406) is fixedly connected to the vertical swing plate (4).

7. The tuned heave plate semi-submersible platform with inertia container according to claim 6, characterized in that: The top of the upper mounting seat (1401) of the spring structure is connected to the top of the upper telescopic structure (6) via bolt II (12), the spring damping vibration isolation structure mounting seat (705) is fixedly connected to the upper mounting seat (1001) of the inertial container via bolt I (8) and nut I (9), and the top of the pull rod (1005) is fixedly connected to the upper flange of the hydraulic cylinder (1006) via a pull rod nut (1003).

8. The tuned heave plate semi-submersible platform with inertia container according to claim 2, characterized in that: The semi-submersible platform (1), the column (2), the upper telescopic structure (6), the lower telescopic structure (11) and the heave plate (4) are made of a material having a density of 7850 kg / m 3 of steel.

9. A structural parameter optimization design method for a tuned heave plate semi-submersible platform including an inertia container, characterized in that: The semi-submersible platform with tuned heave plate containing inertia container according to claim 6 is adopted, and the specific steps include: Step 1: The total masses of the semi-submersible platform (1) and the heave plate (4) are M1 and M2 respectively. When waves act on the semi-submersible platform (1) and the heave plate (4), the semi-submersible platform (1) and the heave plate (4) deviate from the equilibrium position, the spring (702) and the damper (703) in the spring damping vibration isolation structure (7) are compressed or restored, and the piston rod of the hydraulic cylinder (1006) in the open fluid inertial container (10) is pushed. The piston rod moves relative to the hydraulic cylinder (1006) so that the fluid flows along the spiral tube (1004), and the spring structure (14) connected in parallel with the spring damping vibration isolation structure (7) and the open fluid inertial container (10) is compressed or restored, and the tuning heave plate (4) starts to work; Step 2: Perform dynamic analysis on the semi-submersible platform (1), establish a dynamic model of the system, and derive the heave motion transfer function of the model; Step 3: Taking the minimum root mean square value of the heave motion of the semi-submersible platform (1) as the optimization target, so as to optimize the structural parameters of the semi-submersible platform (1) by using fmincon according to different wave conditions; Step 4: Taking the root mean square value of the heave motion of the semi-submersible platform (1) as an evaluation index of the vibration suppression performance, the heave motion suppression performance of the semi-submersible platform containing the inertia container is analyzed.

10. The structural parameter optimization design method of a tuned heave plate semi-submersible platform with an inertia container according to claim 9 is characterized in that: The structural parameters include the stiffness of the spring (702), the compression spring (1405), the damping coefficient of the damper (703), and the inertia coefficient of the open fluid inertia container (10).

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