CN113187847A

CN113187847A - Marine magneto-rheological elastomer vibration-damping buoyant raft

Info

Publication number: CN113187847A
Application number: CN202110459897.4A
Authority: CN
Inventors: 游世辉; 张圣东; 杨俊彦
Original assignee: Zaozhuang University
Current assignee: Zaozhuang University
Priority date: 2021-04-27
Filing date: 2021-04-27
Publication date: 2021-07-30
Anticipated expiration: 2041-04-27
Also published as: CN113187847B

Abstract

The invention provides a magnetorheological elastomer vibration reduction floating raft for a ship, which comprises an elastic base, wherein the top end of the elastic base is sequentially provided with a middle raft body and vibration excitation equipment from bottom to top, the elastic base is connected with the middle raft body through a lower-layer vibration isolator, and the middle raft body is connected with the vibration excitation equipment through an upper-layer vibration isolator. The invention can improve the vibration isolation effect of the floating raft system, and can adjust the rigidity of the raft frame according to the change of the excitation load no matter at low frequency or high frequency.

Description

Marine magneto-rheological elastomer vibration-damping buoyant raft

Technical Field

The invention mainly relates to the technical field of ship vibration reduction, in particular to a magnetorheological elastomer vibration reduction buoyant raft for a ship.

Background

The floating raft vibration isolation is an effective vibration isolation mode and is applied to machines or ships with higher vibration isolation requirements.

According to the small compressor or motor damping floating raft device provided in the patent document with the application number of CN201110202032.6, the product comprises a primary damping device and a secondary damping device, wherein the compressor or the motor is connected with the primary damping device, and the base is connected with the secondary damping device. The primary damping device comprises an anchoring rubber column and a floating raft seat plate, and the compressor or the motor is flexibly connected with the floating raft seat plate through the anchoring rubber column. The second-stage damping device comprises a supporting spring, a buffering rubber cushion, an elastic sleeve, a bolt assembly compressor or a motor, and the base is connected through the two-stage damping device in a flexible connection and flexible supporting mode. When the amplitude generated by the compressor or the motor is transmitted to the base, the amplitude can be weakened by more than 90%, and the working condition of the system and the feeling of a user can be greatly improved.

Although many researchers improve the structure of raft frame, but can not carry out full frequency intelligent control according to 0 ~ 1000Hz equipment excitation frequency, the raft frame is as the isolator of having installed many equipment, and its mechanical properties need adjust according to different equipment excitation frequencies to reach optimal vibration isolation effect.

Disclosure of Invention

The invention mainly provides a magnetorheological elastomer vibration reduction buoyant raft for a ship, which is used for solving the technical problems in the background technology.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a marine magneto-rheological elastomer vibration reduction buoyant raft comprises an elastic base, wherein the top end of the elastic base is sequentially provided with a middle raft body and vibration excitation equipment from bottom to top, the elastic base is connected with the middle raft body through a lower-layer vibration isolator, and the middle raft body is connected with the vibration excitation equipment through an upper-layer vibration isolator;

the middle raft body is internally provided with a plurality of magneto-rheological elastomers, an excitation coil is arranged in each magneto-rheological elastomer, the bottom of each magneto-rheological elastomer is fixed at the top of the middle raft body, and the top of each magneto-rheological elastomer is movable and corresponds to one upper-layer vibration isolator in position;

the lower-layer vibration isolator comprises a plurality of vibration reduction springs and a plurality of groups of vibration reduction assemblies, wherein the vibration reduction springs are connected with the lower surface of the middle raft body and the upper surface of the elastic base;

damping subassembly connects two including locating the first cylinder at elastic pedestal both ends respectively the scissors formula coupling assembling of first cylinder piston rod execution end, scissors formula coupling assembling each department of bending all is equipped with the vibration isolation spring, and every vibration isolation spring all leans on with middle raft body lower surface counterbalance.

Furthermore, folding telescopic link bottom is connected with rotates adjustment mechanism, rotate adjustment mechanism including offer in the recess on elastic base top is fixed in the inside first electronic guide rail of recess, with first electronic guide rail top sliding connection's first slider is fixed in the second cylinder on first slider top, and be fixed in rotation axis on the piston rod of second cylinder makes folding telescopic link can concentrate near the rotation axis fast to the relatively poor region of rigidity cushions in the middle raft body through the vibration isolation spring on the folding telescopic link.

Furthermore, every the rotation axis outer peripheral face all imbeds and has a plurality of first balls, and is a plurality of first ball encircles the radial planar axis of rotation axis and sets up equidistance one by one to prevent to produce dry friction between rotation axis and the swivel becket, prolonged the life of rotation axis and swivel becket.

Furthermore, a plurality of supplies have been seted up on the folding telescopic link the swivel becket of rotation axis interlude to guide folding telescopic link to concentrate near the rotation axis fast, and cushion the relatively poor region of rigidity in the middle raft body through the vibration isolation spring on the folding telescopic link.

Further, every the top of vibration isolation spring all be fixed with the supporting disk that middle raft body bottom surface leaned on, every the top of supporting disk all imbeds there is the second ball to prevent to produce the dry friction between vibration isolation spring and the middle raft body bottom surface, thereby prolong the life of vibration isolation spring and middle raft body.

Further, the content percentage of the magnetic particles in the magnetorheological elastomer is 27%.

Furthermore, the elastic base is including being fixed in the damping cover of lower floor's isolator bottom is fixed in the leaf spring of damping cover internal surface, and be fixed in the leaf spring bottom and with the rubber slab that the damping cover was pegged graft mutually for be fixed in the damping cover of lower floor's isolator bottom and lie in subaerial between the rubber slab, can further absorb the vibration through the leaf spring.

Further, the inner wall fixed surface that the damping covers has the first neodymium magnet that the symmetry set up, first neodymium magnet bottom is equipped with second neodymium magnet, second neodymium magnet and first neodymium magnetism nature repel each other, second neodymium magnet is fixed in the top surface of rubber slab, through the characteristic that the second neodymium magnetism nature on first neodymium magnet on the damping covers and the rubber slab repels each other to further cushion the damping cover.

Further, first cylinder top is connected with slide mechanism, slide mechanism including the embedding in the electronic guide rail of second on middle raft body bottom surface, with electronic guide rail sliding connection of second just is fixed in the second slider on first cylinder top surface to make things convenient for the folding telescopic link of first cylinder quick control to fold and extend, prevent that first cylinder from stretching out the damping raft because of the overlength, and then the influence is used.

Furthermore, middle raft body external fixation has the PLC controller, the PLC controller is in order to realize data interaction with first cylinder, second cylinder and excitation coil electric connection to dynamic response can be solved to the resonance load effect of different frequencies, vibration damping performance evaluation later provides the basis.

Compared with the prior art, the invention has the beneficial effects that:

firstly, this magnetic current becomes elastomer buoyant raft can promote the vibration isolation effect of buoyant raft system, no matter at low frequency or high frequency, all can be according to the rigidity of the change adjustment raft frame of excitation load. For the raft frame that needs to install many equipment, it is necessary that can adjust the vibration isolation effect of raft frame according to the vibration frequency of different equipment. The vibration isolation effect is excellent within the vibration range of 0-1000 Hz, and the maximum vibration isolation effect can reach 45 dB.

Secondly, the invention can realize the simultaneous vibration isolation of low frequency and high frequency, which specifically comprises the following steps: the vibration exciting frequency is used as guidance, the current of the built-in magnet exciting coil is changed, the local rigidity of the raft body is adjusted, and optimal vibration isolation is carried out in a device-by-device mode.

The present invention will be explained in detail below with reference to the drawings and specific embodiments.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is an isometric view of the present invention;

FIG. 3 is an exploded view of the present invention;

FIG. 4 is a schematic structural view of the damping assembly of the present invention;

FIG. 5 is a schematic view of the structure of the elastic base of the present invention;

FIG. 6 is a schematic view of the folding telescopic rod of the present invention;

FIG. 7 is a schematic view of the rotation adjustment mechanism of the present invention;

FIG. 8 is an enlarged view of the structure in area A of FIG. 4;

FIG. 9 is a graph of stiffness as a function of current;

FIG. 10 is a graph of power flow drop contrast curves from 1 to 5A;

FIG. 11 is a power flow drop contrast plot of 6-10A;

fig. 12 is a graph of power flow step and field current for optimal control.

In the figure: 10. an elastic base; 11. a vibration damping cover; 12. a plate spring; 13. a rubber plate; 20. a lower layer vibration isolator; 21. a vibration reduction assembly; 211. a first cylinder; 212. folding the telescopic rod; 2121. a rotating ring; 213. a vibration isolation spring; 2131. a second ball bearing; 2132. a support disc; 214. a rotation adjustment mechanism; 2141. a rotating shaft; 2142. a second cylinder; 2143. a first motorized rail; 2144. a groove; 2145. a first slider; 2146. a first ball bearing; 215. a sliding mechanism; 2151. a second motorized rail; 2152. a second slider; 22. a damping spring; 30. a middle raft body; 31. a field coil; 32. a magnetorheological elastomer; 33. a PLC controller; 40. an upper vibration isolator; 50. and (5) a vibration excitation device.

Detailed Description

In order to facilitate an understanding of the invention, the invention will now be described more fully hereinafter with reference to the accompanying drawings, in which several embodiments of the invention are shown, but which may be embodied in different forms and not limited to the embodiments described herein, but which are provided so as to provide a more thorough and complete disclosure of the invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may be present, and when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present, as the terms "vertical", "horizontal", "left", "right" and the like are used herein for descriptive purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the knowledge of the terms used herein in the specification of the present invention is for the purpose of describing particular embodiments and is not intended to limit the present invention, and the term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

In an embodiment, referring to fig. 1 to 8, in a preferred embodiment of the present invention, a magnetorheological elastomer vibration damping raft for a ship includes an elastic base 10, wherein a middle raft 30 and a vibration excitation device 50 are sequentially disposed on a top end of the elastic base 10 from bottom to top, the elastic base 10 and the middle raft 30 are connected by a lower layer vibration isolator 20, and the middle raft 30 and the vibration excitation device 50 are connected by an upper layer vibration isolator 40;

the middle raft body 30 is internally provided with a plurality of magneto-rheological elastomers 32, an excitation coil 31 is arranged in each magneto-rheological elastomer 32, the bottom of each magneto-rheological elastomer 32 is fixed at the top of the middle raft body 30, and the top of each magneto-rheological elastomer is movable and corresponds to one upper-layer vibration isolator 40;

the lower-layer vibration isolator 20 comprises a plurality of damping springs 22 which are connected with the lower surface of the middle raft body 30 and the upper surface of the elastic base 10, and a plurality of groups of damping assemblies 21 which are arranged on the upper surface of the elastic base 10;

the vibration reduction assembly 21 comprises first air cylinders 211 respectively arranged at two ends of the elastic base 10 and a scissors type connecting assembly 212 connected with the actuating ends of piston rods of the two first air cylinders 211, each bending part of the scissors type connecting assembly 212 is provided with a vibration isolation spring 213, and each vibration isolation spring 213 is abutted against the lower surface of the middle raft body 30;

it should be noted that, in this embodiment, based on the formula of vibration power flow of the vibration system: and P is F.V, F and V are instantaneous values representing the acting force and the speed of a certain point of the system respectively, so that when the exciting coil 31 is electrified in the same direction, the bottom of the exciting coil 31 is set to be fixedly restrained, Maxwell stress boundary conditions are set at the boundary inside the middle raft body 30, and z-direction resonant load of 0-1000 Hz and 2000N is applied to the top surface of the equipment model. The model is divided into grids by using a free tetrahedron, the research steps of Comsol are set as follows when solving, step 1 calculates the magnetic field generated by four excitation coils 31, step 2 realizes the magnetic coupling of force and calculates the stress distribution under the magnetic field, step 3 and step 4 calculate the response of the coupled middle raft 30 under the resonance load of 0-1000 Hz, according to the solving result, power flow data are extracted from the top end of the upper vibration isolator 40 and the bottom end of the lower vibration isolator 20 and respectively used as input power flow and output power flow, the power flow drop is calculated in Matlab, the excitation current of the excitation coils 31 is adjusted to improve the vibration damping effect of the floating raft under different vibration exciting loads, the optimal excitation current corresponding to each frequency band can be extracted for quantitatively controlling the vibration damping of the floating raft, namely the current corresponding to the maximum power flow drop, so far, for different vibration exciting devices 50 installed on the same raft, the current value can be introduced according to the vibration exciting load frequency, and the corresponding power flow fall is carried out;

further, in order to compare the vibration isolation effect, the common plate type raft frame and the hollow-out type raft frame are respectively calculated, according to the difference calculation result, power flow data are extracted from the top end of the upper layer vibration isolator 40 and the bottom end of the lower layer vibration isolator 20 and are respectively used as an input power flow and an output power flow, the power flow drop is calculated in Matlab, and the result is shown in fig. 10 and 11, and can be seen from the graph: in the low frequency range below 300Hz, the number of valleys occurring is large because the natural frequency is mainly concentrated in the low frequency band; when the system is resonant, the value of the input power flow is not much different from the value of the output power flow, i.e. P_inThe closer to P_outThe smaller the vibration isolation effect, the worse the vibration isolation effect; according to the previous research, the larger the current is, the larger the overall rigidity of the floating raft of the magnetorheological elastomer is, so that the vibration isolation effect is better when the exciting current is 6-10A for the medium-frequency exciting load of 300-600 Hz, and the vibration isolation effect can reach about 30 dB. For high-frequency load above 600Hz, the effect is better when the current is 3 and 4A, and can reach about 30 dB. The method just accords with the vibration reduction design concept of low frequency high rigidity, high frequency low rigidity; it can also be seen from the figure that, for the raft with low rigidity (with 1-5A current), a formant is easy to appear in the high frequency stage compared with the raft with high rigidity (with 6-10A current), and the raft with high rigidity is relatively flat, because the raft with high rigidity has stronger ability of resisting deformation and absorbs more energy in the vibration process.

Further, the four mounting points of the upper vibration isolator 40 are installed right above the exciting coil 31, because the magnetic field generated in this region is locally strongest, and has the best magnetic effect, so that the local rigidity can be adjusted. In other areas of the raft frame, the magnetic fields of the magnet exciting coils 31 are superposed to generate a stronger magnetic field, so that the overall rigidity of the raft frame can be adjusted;

furthermore, by taking the excitation frequency as a guide, the method proposes that the local rigidity of the intermediate raft body 30 is adjusted by changing the current of the built-in excitation coil 31, and the excitation equipment 50 is subjected to optimal vibration isolation in equipment-based mode;

furthermore, four excitation coils 31 are uniformly arranged on the intermediate raft body 30, the radius of each excitation coil 31 is 100mm, the height of each excitation coil 31 is 210mm, the bottom surface of each excitation coil 31 is set to be fixedly constrained, z-direction displacement w is applied to the top surface to be-10 mm, the rigidity is determined by calculating the magnitude of the reaction force of the bottom surface, 0-10A of current is sequentially introduced into each excitation coil 31, the calculated rigidity value is shown in fig. 9, and as seen from the figure, the rigidity is nonlinearly increased along with the increase of the current, because the elastic modulus of the magnetorheological elastomer 32 is nonlinearly changed along with an external magnetic field;

further, adjusting the current generated by the exciting coil 31 can improve the vibration reduction effect of the floating raft under different excitation loads, and in order to quantitatively control the vibration reduction of the floating raft, the optimal excitation current corresponding to each frequency band, that is, the current corresponding to the maximum power current drop value, can be extracted, so far, for different devices installed on the same raft body, the current values can be introduced according to the excitation load frequency, and the corresponding power current drops are represented by the graph 12.

Specifically, please refer to fig. 3, 4 and 7 again, in another preferred embodiment of the present invention, the bottom end of the folding telescopic rod 212 is connected with a rotation adjusting mechanism 214, the rotation adjusting mechanism 214 includes a groove 2144 formed at the top end of the elastic base 10, a first electric guide rail 2143 fixed inside the groove 2144, a first sliding block 2145 slidably connected to the top end of the first electric guide rail 2143, a second air cylinder 2142 fixed to the top end of the first sliding block 2145, and a rotating shaft 2141 fixed to a piston rod of the second air cylinder 2142, a plurality of first balls 2146 are embedded in an outer circumferential surface of each rotating shaft 2141, the plurality of first balls 2146 are equidistantly arranged around a central axis of a radial plane of the rotating shaft 2141, the folding telescopic rod 212 is provided with a plurality of rotating rings 2121 through which the rotating shaft 2141 is inserted, a supporting plate 2132 abutting against a bottom end surface of the intermediate raft 30 is fixed to the top end of the vibration isolating spring 213, a second ball 2131 is embedded in the top end of each supporting disc 2132;

it should be noted that, in this embodiment, when the first electric guide rail 2143 on the elastic base 10 drives the first sliding block 2145 thereon to slide, the second air cylinder 2142 is fixed on the first sliding block 2145, so as to drive the second air cylinder 2142 and the rotating shaft 2141 on the piston rod thereof to translate until the rotating shaft 2141 moves to an area with poor rigidity in the intermediate raft body 30 under the control of the PLC controller 33, and then the piston rod of the second air cylinder 2142 drives the rotating shaft 2141 to ascend until the rotating shaft 2141 passes through a hinge point of a connecting rod in the folding telescopic rod 212, so that the folding telescopic rod 212 can rotate with the rotating shaft 2141 as a rotation center, at this time, the folding telescopic rod 212 can be rapidly concentrated near the rotating shaft 2141, and the vibration isolation spring 213 on the folding telescopic rod 212 buffers the area with poor rigidity in the intermediate raft body 30;

further, the rotating shaft 2141 is allowed to roll by the first ball 2146 thereon on the rotating ring 2121 of the folding telescopic rod 212, thereby preventing dry friction between the rotating shaft 2141 and the rotating ring 2121, and thus prolonging the service life of the rotating shaft 2141 and the rotating ring 2121;

further, since the folding telescopic rod 212 is composed of a plurality of connecting rods hinged to each other, the folding telescopic rod 212 guides the rotating shaft 2141 to pass through by the rotating ring 2121 arranged at the hinge of two of the connecting rods, so that the connecting rods rotate around the rotating ring 2121 as the rotating center, thereby guiding the folding telescopic rod 212 to quickly concentrate near the rotating shaft 2141, and cushioning the region with poor rigidity in the intermediate raft 30 by the vibration isolation springs 213 on the folding telescopic rod 212;

further, when the vibration isolation spring 213 is driven by the folding telescopic rod 212 to translate, the second rolling balls 2131 on the supporting disc 2132 of the vibration isolation spring 213 roll on the bottom end surface of the intermediate raft body 30, so that dry friction between the vibration isolation spring 213 and the bottom end surface of the intermediate raft body 30 is prevented, and the service lives of the vibration isolation spring 213 and the intermediate raft body 30 are prolonged.

Specifically, referring to fig. 2, 3 and 4, in another preferred embodiment of the present invention, the magnetic-particle-content percentage of the magnetorheological elastomer 32 is 27%;

it should be noted that, in this embodiment, the optimal particle content percentage of the magnetorheological elastomer is 27%, based on the research, parameters of the isotropic magnetorheological elastomer with a particle volume fraction of 30% are adopted, and specific parameters are shown in table 1;

TABLE 1 parameter table of magnetorheological elastomer raft frame

In particular, with reference to fig. 1, 2 and 5 in particular, in another preferred embodiment of the invention, the elastic base 10 includes a vibration-damping cap 11 fixed to the bottom end of the lower vibration isolator 20, a plate spring 12 fixed to the inner surface of the vibration-damping cap 11, and a rubber plate 13 fixed to the bottom end of the plate spring 12 and inserted into the vibration-damping cover 11, first neodymium magnets 111 which are symmetrically arranged are fixed on the inner wall surface of the vibration reduction cover 11, a second neodymium magnet 131 is arranged at the bottom end of the first neodymium magnet 111, the second neodymium magnet 131 magnetically repels the first neodymium magnet 111, the second neodymium magnet 131 is fixed to the top surface of the rubber plate 13, the top end of the first cylinder 211 is connected with a sliding mechanism 215, the sliding mechanism 215 comprises a second electric guide rail 2151 embedded in the bottom end surface of the intermediate raft 30, a second slider 2152 slidably coupled to the second motor guide 2151 and fixed to a top surface of the first cylinder 211;

in the present embodiment, the vibration can be further absorbed by the plate spring 12 between the damper cover 11 fixed to the bottom end of the lower vibration isolator 20 and the rubber plate 13 located on the ground;

further, when the vibration reduction cover 11 moves downward, the vibration reduction cover 11 is further buffered by the characteristic that the first neodymium magnet 111 on the vibration reduction cover 11 and the second neodymium magnet 131 on the rubber plate 13 magnetically repel each other;

further, make first cylinder 211 and second slider 2152 on it can slide to the regional below that rigidity is relatively poor in middle raft body 30 with the help of second electronic guide rail 2151 to make things convenient for first cylinder 211 to control folding telescopic link 212 fast and fold and extend, prevent that first cylinder 211 from stretching out the damping raft because of the overlength, and then the influence is used.

Specifically, please refer to fig. 1, 2, 3 and 4 again, in another preferred embodiment of the present invention, a PLC controller 33 is fixed outside the intermediate raft 30, and the PLC controller 33 is electrically connected to the first cylinder 211, the second cylinder 2142 and the excitation coil 31 to realize data interaction;

it should be noted that, in this embodiment, because the PLC controller 33 is electrically connected to the first cylinder 211, the second cylinder 2142, and the excitation coil 31, and because the system is a coupling process between a complex force field, a magnetic field, and vibration, the PLC controller 33 uses a finite element method to input parameters such as mass, stiffness, and damping of each part into the Comsol, and then solve the parameters, the Comsol can calculate the natural frequency of the system under the condition of force magnetic coupling and perform modal research, and can solve dynamic response to the resonant load action of different frequencies, thereby providing a basis for subsequent vibration damping performance evaluation.

The specific operation mode of the invention is as follows:

when the vibration reduction floating raft is used, based on a vibration power flow formula of a vibration system: p is F · V, and F and V are instantaneous values representing the acting force and the speed of a certain point of the system, respectively, so that when currents in the same direction are applied to the excitation coil 31, the bottom of the excitation coil 31 is set to be fixedly constrained, a Maxwell stress boundary condition is set at the boundary inside the intermediate raft body 30, and a z-direction resonant load of 0-1000 Hz and 2000N is applied to the top surface of the equipment model;

because the PLC 33 is electrically connected with the first cylinder 211, the second cylinder 2142 and the excitation coil 31, and the system is a coupling process among a complex force field, a magnetic field and vibration, the PLC 33 adopts a finite element method, and parameters such as mass, rigidity and damping of each part are input into the Comsol, and then solution is carried out, the Comsol can calculate the natural frequency of the system under the condition of force magnetic coupling and carry out modal research, and dynamic response can be solved for the resonance load action of different frequencies, thereby providing a foundation for the subsequent vibration damping performance evaluation;

the model is divided into grids by using a free tetrahedron, the research steps of Comsol are set as follows when solving, step 1 calculates the magnetic field generated by four excitation coils 31, step 2 realizes the magnetic coupling of force and calculates the stress distribution under the magnetic field, step 3 and step 4 calculate the response of the coupled middle raft 30 under the resonance load of 0-1000 Hz, according to the solving result, power flow data are extracted from the top end of the upper vibration isolator 40 and the bottom end of the lower vibration isolator 20 and respectively used as input power flow and output power flow, the power flow drop is calculated in Matlab, the excitation current of the excitation coils 31 is adjusted to improve the vibration damping effect of the floating raft under different vibration exciting loads, the optimal excitation current corresponding to each frequency band can be extracted for quantitatively controlling the vibration damping of the floating raft, namely the current corresponding to the maximum power flow drop, so far, for different vibration exciting devices 50 installed on the same raft, the current value can be introduced according to the vibration exciting load frequency. Dropping its corresponding power flow.

The invention is described above with reference to the accompanying drawings, it is obvious that the invention is not limited to the above-described embodiments, and it is within the scope of the invention to adopt such insubstantial modifications of the inventive method concept and solution, or to apply the inventive concept and solution directly to other applications without modification.

Claims

1. The marine magneto-rheological elastomer vibration reduction buoyant raft comprises an elastic base (10), and is characterized in that the top end of the elastic base (10) is sequentially provided with a middle raft body (30) and vibration excitation equipment (50) from bottom to top, the elastic base (10) is connected with the middle raft body (30) through a lower-layer vibration isolator (20), and the middle raft body (30) is connected with the vibration excitation equipment (50) through an upper-layer vibration isolator (40);

the middle raft body (30) is internally provided with a plurality of magneto-rheological elastomers (32), an excitation coil (31) is arranged in each magneto-rheological elastomer (32), the bottom of each magneto-rheological elastomer (32) is fixed at the top of the middle raft body (30), and the top of each magneto-rheological elastomer is movable and corresponds to one upper-layer vibration isolator (40);

the lower-layer vibration isolator (20) comprises a plurality of damping springs (22) which are connected with the lower surface of the middle raft body (30) and the upper surface of the elastic base (10), and a plurality of groups of damping assemblies (21) which are arranged on the upper surface of the elastic base (10);

damping subassembly (21) are including locating first cylinder (211) at elastic base (10) both ends respectively, connect two scissors formula coupling assembling (212) of first cylinder (211) piston rod execution end, scissors formula coupling assembling (212) each department of bending all is equipped with vibration isolation spring (213), and every vibration isolation spring (213) all leans on with middle raft body (30) lower surface counterbalance.

2. The marine magnetorheological elastomer vibration damping raft according to claim 1, wherein a rotation adjusting mechanism (214) is connected to the bottom end of the folding telescopic rod (212), the rotation adjusting mechanism (214) comprises a groove (2144) formed in the top end of the elastic base (10), a first electric guide rail (2143) fixed inside the groove (2144), a first sliding block (2145) slidably connected to the top end of the first electric guide rail (2143), a second cylinder (2142) fixed to the top end of the first sliding block (2145), and a rotating shaft (2141) fixed to the piston rod of the second cylinder (2142).

3. The magnetorheological elastomer vibration damping raft for ships according to claim 2, wherein a plurality of first balls (2146) are embedded in the outer circumferential surface of each rotating shaft (2141), and the first balls (2146) are arranged around the central axis of the radial plane of the rotating shaft (2141) at equal intervals one by one.

4. The marine magnetorheological elastomer vibration damping raft according to claim 3, wherein the folding telescopic rod (212) is provided with a plurality of rotating rings (2121) for the rotating shaft (2141) to penetrate through.

5. The marine magnetorheological elastomer vibration damping raft according to claim 1, wherein a support plate (2132) abutting against the bottom end surface of the intermediate raft body (30) is fixed at the top end of each vibration isolation spring (213), and second balls (2131) are embedded in the top end of each support plate (2132).

6. The marine magnetorheological elastomer vibration damped raft of claim 1, wherein the magnetorheological elastomer (32) has a magnetic particle content percentage of 27%.

7. The marine magnetorheological elastomer vibration damping raft according to claim 1, wherein the elastic base (10) comprises a vibration damping cover (11) fixed to the bottom end of the lower vibration isolator (20), a plate spring (12) fixed to the inner surface of the vibration damping cover (11), and a rubber plate (13) fixed to the bottom end of the plate spring (12) and inserted into the vibration damping cover (11).

8. A magnetorheological elastomer vibration damping raft according to claim 7, wherein the inner wall surface of the vibration damping cover (11) is fixed with symmetrically arranged first neodymium magnets (111), the bottom end of the first neodymium magnet (111) is provided with a second neodymium magnet (131), the second neodymium magnet (131) is magnetically repulsive to the first neodymium magnet (111), and the second neodymium magnet (131) is fixed on the top end surface of the rubber plate (13).

9. The marine magnetorheological elastomer vibration damping raft according to claim 1, wherein a sliding mechanism (215) is connected to the top end of the first cylinder (211), the sliding mechanism (215) comprises a second electric guide rail (2151) embedded in the bottom end surface of the intermediate raft body (30), and a second slider (2152) which is connected with the second electric guide rail (2151) in a sliding manner and fixed to the top end surface of the first cylinder (211).

10. The marine magnetorheological elastomer vibration damping raft according to claim 1, wherein a PLC (programmable logic controller) controller (33) is fixed outside the middle raft body (30), and the PLC controller (33) is electrically connected with the first cylinder (211), the second cylinder (2142) and the excitation coil (31) to realize data interaction.