61 results about "Viscoelastic damping" patented technology

The invention belongs to the technical field of structural engineering, and relates to a self-resetting lateral force resisting module suitable for a beam through type frame. According to the technical scheme, a rotating support is an obtuse-angle triangular frame composed of an inclined support and a horizontal beam, the obtuse-angle top of the obtuse-angle triangular frame is hinged to the bottom of an upper-layer main beam of a beam-through type frame, and the center of the horizontal beam of the obtuse-angle triangular frame is connected with a thorn ring-disc spring reset system; the acute angle of the obtuse triangle frame is connected with an inner wedge-shaped plate-disc spring reset system and an outer wedge-shaped plate-disc spring reset system; the viscoelastic damping groove is connected to the lower portion of the horizontal beam and located between the thorn ring-disc spring reset system and the inner wedge-shaped plate-disc spring reset system and the outer wedge-shaped plate-disc spring reset system. The bottoms of the thorn ring-disc spring reset system, the viscoelastic damping groove, the inner wedge-shaped plate-disc spring reset system and the outer wedge-shaped plate-disc spring reset system are fixedly connected with the upper portion of a lower layer main beam of the beam through type frame. The characteristics of a beam through type steel frame are fully matched, and the weak layer effect of the beam through type steel frame in the application of a high-rise building structure in the background technology is solved.

The invention discloses a multi-stage assembly type viscoelasticity-metal toughness damper and a vibration reduction method, and belongs to the technical field of engineering structure vibration reduction. The damper comprises a viscoelastic damper unit, a metal damper unit and an SMA self-resetting unit. The viscoelastic damper unit is composed of a constraint steel plate and a viscoelastic material layer which are laminated, and the two ends of the viscoelastic damper unit are connected with the first connecting plate and the second connecting plate correspondingly. The metal damper unit comprises outer restraining plates arranged on the two sides of the viscoelastic unit and metal energy dissipation webs connected between the outer restraining plates and the connecting plates. The SMA self-resetting unit comprises a force transmission steel plate, a stress steel plate and an SMA component. According to the damper, the viscous-elastic material is used for shearing and dissipating energy under small shock or wind vibration, the SMA component provides reset force, and the metal web keeps elasticity; the metal webs conduct buckling energy dissipation under medium earthquakes or large earthquakes and work in cooperation with the viscoelastic units and the SMA units, the energy dissipation capacity is remarkably improved, and residual deformation is controlled. The device has the advantages of multi-stage collaborative energy consumption, good self-resetting performance, assembling capability and easiness in maintenance.

The invention relates to the technical field of cables, provides an environment-friendly marine cable, and aims to solve the technical problem that an existing marine cable is insufficient in comprehensive protection capability. The cable sequentially comprises a cable core conductor, an insulating layer, an inner protective layer, a viscoelastic damping and stress decoupling layer, a dual-function sacrificial hydrogel layer and a high-durability environment-friendly outer sheath from inside to outside. By the adoption of the technical scheme, integrated cooperative protection of the structure and materials can be achieved, dual active protection on moisture and salt mist is provided, the cable is endowed with excellent mechanical stress tolerance, and high environmental protection performance and long-period durability of the cable are guaranteed.

The invention belongs to the technical field of rubber composite materials, and provides a low-noise rubber track composite material and application thereof. A double-filler synergistic damping design of montmorillonite / silicon carbide composite filler and carbon black grafted with a damping functional polymer is adopted, montmorillonite is loaded on the surface of silicon carbide in an intercalation-stripping composite structure, the stripping degree is 60-90%, the polymer is grafted on the surface of carbon black through a silane coupling agent, the grafting density is 0.3-0.8 chains / nm < 2 >, the mass ratio of the two fillers is 1.5: 1-3: 1, and the damping functional polymer is grafted on the surface of carbon black through a silane coupling agent. And a dual noise reduction mechanism in which rigidity enhancement and viscoelastic damping are cooperated is formed. The loss factor tan delta is larger than or equal to 0.15 in the frequency range of 20-1000 Hz, and compared with a conventional material, the noise is reduced by 10-30 dB. The invention solves the technical problems of poor damping effect and weak noise control capability of the traditional rubber track material, and has wide application value in the fields of engineering machinery tracks, automobile tires, shock absorption and noise reduction materials and the like.

The utility model discloses a double-sided plane grinding and polishing machine, which relates to the technical field of grinding and polishing equipment, aims to solve the technical problem that ultrathin or fragile products are easily damaged by the current double-sided lapping machine, and comprises a double-sided lapping machine, an outer matching ring, a lower grinding disc, a butt joint seat and a wandering star wheel. The wandering star wheel is composed of the hollowed-out ring and the butt joint gear ring, the reinforcing frame is arranged in the hollowed-out ring, on the premise that the strength of the wandering star wheel is guaranteed, unnecessary materials are removed, the mass of the wandering star wheel is reduced, and therefore inertia is reduced, meanwhile, a composite buffering structure is arranged in the wandering star wheel, and the service life of the wandering star wheel is prolonged. The first buffer layer of the composite buffer structure is made of elastic rubber and can absorb most impact force generated by inertia of the wandering star wheel, the damping layer is made of viscoelastic damping materials and can effectively restrain transmission of vibration, and the second buffer layer is made of silica gel and further buffers and disperses acting force on a product. And the phenomenon that ultrathin or fragile products are damaged in the machining process can be effectively avoided.

The utility model discloses a magnetorheological sound insulation cotton damping with anti -interference structure relates to sound insulation material technical field, including sound insulation cotton layer and anti -interference structure layer. The composite electromagnetic shielding layer of the magnetorheological sound insulation cotton damping with anti -interference structure outermost layer is alternately woven composite by nanometer copper net and graphene film, can be all -round shielding to electromagnetic interference, creates stable electromagnetic environment for the inside magnetorheological liquid filling cavity, effectively avoids the outside electromagnetic signal interference magnetorheological liquid response to the magnetic field, guarantees its rheological characteristic stable play, the three -dimensional shock attenuation layer of inner layer adopts the even arrangement of hexagonal honeycomb -like elastic rubber film and viscoelastic damping block, and is matched with interval distribution's shock attenuation spring and shock attenuation rubber block, can form multistage shock attenuation system, effectively absorbs and buffers mechanical vibration, greatly reduced the influence of outside vibration to sound insulation cotton layer and magnetorheological liquid filling cavity, has improved the reliability of product under complex vibration environment significantly.

The invention discloses a self-repairing road concrete pipe with an anti-seismic structure, and relates to the technical field of civil engineering materials and structural seismic resistance. The structure comprises a concrete pipe joint, a repairing liquid main pipe network, an asphalt damping bonding layer and a high-density polyethylene exoskeleton which are sequentially and coaxially arranged from inside to outside, and the repairing liquid main pipe network is attached to the outer wall of the concrete pipe joint and filled with repairing liquid; the asphalt damping bonding layer coats the asphalt damping layer and the asphalt damping layer and provides viscoelastic damping; the high-density polyethylene exoskeleton is arranged outside in a sleeving mode, a mechanical weak line is arranged on the pipe wall of the high-density polyethylene exoskeleton, and seismic resistance and self-repairing are achieved through a three-stage mechanism: in the first stage, the exoskeleton dissipates main energy through plastic deformation of the weak line; in the second stage, the asphalt layer absorbs residual energy through viscous deformation; and in the third stage, when the concrete pipe cracks, the asphalt layer transmits deformation to the repairing liquid pipe network and enables the repairing liquid pipe network to be broken, and precise self-repairing is achieved. The structure integrates efficient energy consumption and repairing functions, and the anti-seismic toughness and durability of the underground pipeline are improved.

The present invention provides a damping rubber composition that can form a damping member with excellent damping properties in low-strain areas such as wind sway, while suppressing adhesion to rolls and having good processability. [Solution] The damping rubber composition contains (a) a base rubber, (b) a tackifier, (c) carbon black, (d) an inorganic filler with a particle size of 3 μm or more as measured by the air permeability method, and (e) a fatty acid derivative as a lubricant, wherein the (a) base rubber contains at least one selected from the group consisting of polyisoprene rubber and polybutadiene rubber, and the amount of (b) tackifier is 70 to 110 parts by mass, the amount of (c) carbon black is 100 to 160 parts by mass, the amount of (d) inorganic filler is 5 to 100 parts by mass, and the amount of (e) lubricant is 0.5 to 10 parts by mass per 100 parts by mass of the (a) base rubber.

The invention discloses a hybrid self-resetting support provided with a rate-dependent viscoelastic damper, which belongs to the technical field of seismic resistance of structural engineering, and comprises an outer pipe, an inner plate, a viscoelastic damper, a shape memory alloy U-shaped damper and channel steel, the viscoelastic damper is formed by stacking a viscoelastic material layer and a steel plate, is fixed between the inner plate and the outer pipe, and is arranged at the end part of the inner plate; when an earthquake acts, the inner plate moves in the axial direction relative to the outer pipe, the viscoelastic material layer is driven to be subjected to shear deformation, and damping force related to the loading frequency is provided; in addition, a plurality of shape memory alloy U-shaped dampers are arranged between the inner plate and the outer pipe at intervals in the supporting axial direction, and the self-resetting capacity is provided through bending deformation. The U-shaped damper and the viscoelastic damper are stressed in parallel, damping energy consumption and restoring force are generated at the same time, the floor acceleration and the base shearing force can be effectively reduced, and the device has the advantages of being simple in structure and reliable in connection.

To provide a viscoelastic damper capable of suppressing deterioration over time due to temperature changes in the installation environment. [Solution] The viscoelastic damper comprises a pair of plate-shaped bodies, a viscoelastic body arranged between the pair of plate-shaped bodies, and a sealing member that isolates the viscoelastic body from the outside, and the sealing member is arranged between the pair of plate-shaped bodies at a position away from the outer peripheral surface of the viscoelastic body.

damping device (40) for an optical system, in particular a projection optic (10) of a lithography system (1), comprising - a supporting, first element (42), in particular a support frame (34) for receiving at least one optical element (36); - a second element (50) incorporated in the first element (42), in particular the optical element (36); and - at least one damping element (38) arranged between the first element (42) and the second element (50), in particular a mechanical end stop, wherein the damping element (38) has a liquid crystalline elastomer (48) with viscoelastic damping properties.

The invention discloses a combined support combining a bio-based composite material framework and a high-performance filling material and a preparation process of the combined support, and belongs to the technical field of bridge engineering materials. According to the support, a porous net-shaped framework is made of a polylactic acid-based composite material, an interface bonding layer is formed on the inner surface of a framework pore through a bio-based polyurethane adhesive, and natural rubber, a viscoelastic damping material or a shape memory alloy complex is poured to serve as a high-performance filling material. The preparation process comprises the key steps of framework compression molding, interface treatment, vacuum pressure filling, segmented vulcanization and the like. According to the technical scheme, through the synergistic effect of the bio-based framework and the functional filling body, the bearing stability and environmental adaptability of the support are remarkably improved, meanwhile, the advantages of being high in maintainability and low in whole life cycle cost are achieved, the support is particularly suitable for a corrosive environment or a bridge engineering scene with the high anti-seismic requirement, and the application prospect is wide. And the balance between mechanical properties and ecological benefits is realized.

The invention relates to the technical field of building materials, and discloses a multi-surface-layer decorative sound-absorbing partition panel manufacturing process which comprises the steps that a multi-surface-layer decorative panel and a back plate are fixed to form a closed cavity; mixing the composite functional resin system and the curing and synergistic system under a specific pressure, and injecting the mixture into the cavity; and carrying out in-situ reaction at a specific temperature to foam and cure the mixture to form the viscoelastic damping core material which is integrally connected with the panel. The technical core is that the composite functional resin system comprises a self-adaptive interface coupling agent, the coupling agent can spontaneously migrate to the inner surface of the panel and be enriched in the in-situ reaction process, an interface of a core material and the panel is constructed by forming chemical bonding, and a traditional adhesive layer is replaced. The production process is simplified; a traditional adhesive is replaced by chemical bonding, so that the interface bonding strength is improved, and the acoustic bridge effect is avoided; through specific core material components, the board has excellent sound insulation and vibration damping performance.

This utility model discloses a connection structure for a plate viscoelastic damper in a structure, used for connecting the viscoelastic damper to the main structure. It includes: a plate viscoelastic damper, a pin, and connecting parts. The plate viscoelastic damper consists of connecting steel plates on both sides, a connecting steel plate in the middle, and a viscoelastic damping layer. The viscoelastic damping layer is formed by alternating layers of rubber and steel plates, vulcanized and bonded. The connecting parts consist of double-clamped plates, a single-clamped plate, and a pin. This utility model utilizes the pin and connecting parts to connect the viscoelastic damper to the structure, avoiding the high temperatures generated during welding from damaging the rubber layer in the viscoelastic damping layer. It also facilitates later maintenance and replacement of the viscoelastic damper by disassembling the pin. This solves the accuracy and quality problems in the production and installation processes of plate viscoelastic dampers, effectively improving construction efficiency and installation quality.

The application provides an assembled staged viscoelastic-friction composite damper, belonging to the technical field of dampers, which comprises a viscoelastic damping unit, a self-resetting friction damping unit and an intermediate connecting plate, the viscoelastic damping unit and the self-resetting friction damping unit are arranged on the two sides of the intermediate connecting plate; the viscoelastic damping unit and the self-resetting friction damping unit each comprise two fixed plates and one movable plate, the fixed plates are connected to the intermediate connecting plate, and the movable plate is arranged between the two fixed plates; a plurality of viscoelastic material blocks are arranged between the fixed plate and the movable plate of the viscoelastic damping unit, and a plurality of friction plates are arranged between the fixed plate and the movable plate of the self-resetting friction damping unit; a plurality of SMA wires are further connected between the fixed plate and the movable plate of the self-resetting friction damping unit, and the SMA wires are used for limiting the displacement of the movable plate along the length direction of the fixed plate; the application can avoid invalid wear of the self-resetting friction damping unit and damage of the viscoelastic damping unit, and effectively dissipate energy and damp.

The application belongs to the technical field of structural vibration control devices, and discloses a high-stability multidirectional vibration isolator. The vibration isolator comprises horizontally arranged upper and lower steel plates, a spiral spring fixed between the upper and lower steel plates, a threaded sleeve and a viscoelastic damping block. The threaded sleeve is rigidly connected to the upper and lower steel plates and located outside the spiral spring. The viscoelastic damping block is arranged in the spiral spring and fixed below the upper steel plate and above the lower steel plate. The viscoelastic damping block is a curved surface. The application improves the vertical vibration isolation effect and displacement control capacity of the spring vibration isolator, makes up for the horizontal vibration isolation defects caused by the insufficient lateral stability of the spring vibration isolator, increases the application scenarios of the spring vibration isolator, and does not excessively increase the implementation complexity, thereby facilitating application.

Viscoelastic damper assembly applicable both in air and submerged applications and with improved efficiency over prior art solutions for adding damping to an object or structure.

This invention relates to the field of vibration reduction system technology, specifically to a broadband damping composite system, its construction method, and its application. The broadband damping composite system comprises a viscoelastic damping layer, an adhesive layer, and a magnesium alloy restraint layer; the viscoelastic damping layer is made of butyl rubber, acrylate polymer, or polyurethane. This invention also provides a construction method for the broadband damping composite system, including the following steps: bonding the viscoelastic damping layer and the magnesium alloy restraint layer together using an adhesive layer to obtain the broadband damping composite system. This invention further provides an application of the broadband damping composite system obtained by this construction method in steel structure floor slabs. This invention solves the problem that existing building damping systems struggle to simultaneously achieve high energy efficiency, extreme lightweight design, broadband adaptability, and ease of implementation.

The application discloses an electric arc additive and multi-directional loading device cooperative operation welding gun system and a rigidity and damping cooperative control method thereof, the system comprises an anti-vibration welding gun neck assembly, an anti-interference wire feeding hose assembly, a controller and an avoidance trigger sensor; the anti-vibration welding gun neck assembly adopts a multilayer damping composite bellows structure, adjusts the rigidity of the gun neck through circumferentially distributed independent sealed air pressure chambers, and cooperates with a viscoelastic damping layer to realize wideband vibration damping; the anti-interference wire feeding hose assembly adopts an axial partition type electromagnetic shielding structure, cooperates with an active electromagnetic cancellation structure to realize full-band anti-electromagnetic interference; the control method has multiple working modes such as rigid posture keeping, flexible avoidance synchronous arc extinguishing, posture resetting, vibration active suppression, electromagnetic active cancellation and the like. The application effectively solves the vibration interference, electromagnetic interference and collision safety problems during the electric arc additive and multi-directional loading device cooperative operation, and significantly improves the stability and forming quality of the electric arc additive manufacturing process.

The invention provides a shear restraint layer damping type pulse magnet coil and a preparation method thereof, and the pulse magnet coil comprises a coil body which forms an annular magnet structure; the structural shape of the insulating structural body is matched with the appearance of the coil body, and the insulating structural body wraps the outer side of the coil body, is made of an insulating material and is used for limiting the radial deformation of the coil body; and the viscoelastic damping layer is arranged between the coil body and the insulating structural body, wraps the coil body and is made of a viscoelastic material, and the two sides of the viscoelastic damping layer are fixedly connected with the outer surface of the coil body and the inner surface of the insulating structural body respectively. When pulse current is introduced into the coil body to generate vibration, the viscoelastic damping layer generates shear deformation along with vibration of the coil body and the insulation structure body, vibration mechanical energy is converted into heat energy through the viscoelastic material to be dissipated, and meanwhile axial and radial vibration reduction is conducted on the coil body. The structure is simple, the cost is lower, and radial and axial vibration reduction and fatigue resistance of the pulse magnet coil can be considered.

This invention discloses a spacer and a spacer installation system. By connecting a conductor connection mechanism to an insulator, the insulator is fixed to the conductor using the clamps of the conductor connection mechanism. A silicone rubber pad increases the friction between the clamps and the conductor, allowing the conductor to better transfer vibration energy to the conductor connection mechanism during vibration. In the conductor connection mechanism, the viscoelastic damping material of the clamps initially eliminates the transmitted vibration energy. Then, a secondary elimination of vibration energy occurs using a permanent magnet electromagnetic damper composed of a permanent magnet, bearing, and spring. The vibration energy is transmitted to the spring through the bearing, causing the spring to move in the magnetic field generated by the permanent magnet. Based on the principle of electromagnetic induction, the vibration energy is converted into electrical energy and dissipated. Therefore, this invention can absorb the energy brought by conductor vibration, thereby solving the problem of poor stability in transmission lines caused by vibration.

The invention discloses an energy-absorbing, vibration-reducing and noise-reducing high-speed railway viaduct vibration-reducing effect evaluation method, which comprises the following steps: S1, arranging force sensors and displacement sensors in a restraint layer, a base layer and a damping layer of a high-speed railway viaduct structure, and collecting normal stress of the force sensors and the displacement sensors in three-axis directions, shear stress of x-y, y-z and z-x planes and displacement of the force sensors and the displacement sensors in corresponding directions; s2, performing the following assumptions to calculate a loss factor: (1) the viscoelastic damping material satisfies a linear viscoelastic constitutive relationship; (2) the restraint layer and the base layer meet the plane assumption in the vibration process, namely, the deformation is uniform; (3) the influence of shear deformation and rotational inertia of the structure is neglected; s3, determining the circular frequency of the vibration mode and the first-order mode of the constraint damping structure; s4, calculating strain energy of the constraint layer, the damping layer and the base layer; s5, calculating dissipated energy of the damping layer; and S6, calculating a transverse loss factor and a vertical loss factor in the first-order mode.

The invention discloses an anti-vibration optical fiber connector assembly based on inertia decoupling and viscoelastic damping, and belongs to the technical field of optical fiber sensing. The optical fiber connector assembly comprises: a connector housing assembly; the suspension insertion core module is arranged in the connector shell assembly, and the head of the suspension insertion core module is provided with an optical fiber insertion core; the inertial mass unit is arranged at the tail part of the suspension insertion core module; the viscoelastic damping layer is filled in a gap among the suspension insertion core module, the inertia mass unit and the connector shell assembly, so that the suspension insertion core module is supported in the connector shell assembly in a suspension manner; the viscoelastic damping layer is used for absorbing vibration energy transmitted to the connector shell assembly from the outside and is matched with the inertial mass unit to isolate the influence of vibration on the optical fiber insertion core; on the premise that a standard physical interface is reserved, external high-frequency vibration crosstalk is effectively filtered out through physical isolation, photoelastic effect noise and end face reflection fluctuation are eliminated, and the detection precision and stability of the DAS are remarkably improved.

The application discloses a self-resetting viscoelastic damping support, wherein the flange sections of the upper steel member and the lower steel member are bonded by viscoelastic material to form a damping section; the end of the flange section is opposite to the limiting protrusion of the adjacent reinforcing section and is spaced from each other to form a gap section; the center line of the pulling side of the damping section is symmetrically distributed with an alloy cable group in the vertical bonding side direction, the shape memory alloy cable is at a set angle with the center line, and the two ends of each shape memory alloy cable are respectively threaded through the wire guide hole of the upper steel member pulling side and the wire guide hole of the lower steel member pulling side and fixed on the limiting end head, and the limiting end head is held at the wire guide hole adjacent to the limiting end head. The application has simple structure, clear movement mechanism, can well coordinate deformation and movement, and can show good performance under one-way tension and compression or reciprocating load such as earthquake.

The invention discloses a double-shaft decoupling type precision positioning platform containing a viscoelastic damping block, and belongs to the technical field of precision positioning, the double-shaft decoupling type precision positioning platform comprises a mounting base, a composite integrated flexible structure is arranged in the mounting base, and two groups of amplification mechanisms serving as power sources and two groups of decoupling mechanisms matched with the amplification mechanisms are arranged on the flexible structure in different directions; piezoelectric ceramic driving devices are installed in the two amplification mechanisms, an objective table is arranged at the motion center, affected by stretching and retracting of the two amplification mechanisms, of the flexible structure, a plurality of damping blocks are attached to the flexible structure, two micrometer heads connected with the flexible structure are arranged on the outer portion of the side face of the installation base, and micro-nano-scale high-precision positioning can be achieved.

The utility model relates to the technical field of laminated wood reticulated shell nodes, in particular to a laminated wood reticulated shell energy consumption node structure which comprises a steel connecting piece, six metal connecting pieces which are circumferentially arranged at equal angles are fixedly installed on the outer surface of the steel connecting piece, and installation clamping grooves are formed in the metal connecting pieces. A plurality of V-shaped teeth which are linearly arranged at equal intervals are arranged on the surfaces of the two opposite inner sides of the mounting clamping groove, laminated wood is clamped in the mounting clamping groove, a plurality of V-shaped grooves which are linearly arranged at equal intervals are formed in the surfaces of the two opposite sides of the laminated wood, and two connecting bolts used for fixing the laminated wood are in threaded connection with the metal connecting piece. Six first mounting blocks which are circumferentially arranged at equal angles are fixedly mounted on the outer side surface of the steel connecting piece; through the viscoelastic damper, when the whole structure is stressed and deformed, energy is dissipated through shear deformation of a viscoelastic material, the energy dissipation capacity of the joint is effectively improved, and the response of the structure under the dynamic load is reduced.

The invention discloses a mute ABS (Acrylonitrile Butadiene Styrene) composite material and a preparation method thereof. The composite material is prepared from the following components in parts by weight: 70-90 parts of ABS resin, 10-30 parts of TPU (Thermoplastic Polyurethane) resin, 3-6 parts of a compatilizer, 0.5 part of an antioxidant and 0.4-0.6 part of a lubricant. By adding the damping TPU resin with high viscoelasticity into the ABS resin, the noise performance of the mute ABS composite material is obviously improved compared with that of common ABS resin, abnormal sound generated in the using process of plastic parts can be greatly reduced, and meanwhile, the mute ABS composite material has high toughness and can be widely applied to the industries of household appliances, automobiles, electronic appliances and the like.

The airborne equipment back vibration isolator comprises a mounting beam, a center shaft and a knuckle bearing, the two ends of the center shaft vertically penetrate through the upper end and the lower end of the mounting beam correspondingly and then are coaxially and fixedly connected with two viscoelastic damping blocks correspondingly, and the two viscoelastic damping blocks are fixed to the upper end and the lower end of the mounting beam correspondingly in a limiting mode; one end of the knuckle bearing is arranged on the center shaft in a sleeving mode, the other end of the knuckle bearing is horizontally and fixedly connected with a first shell and an axial damping piece located in the first shell, and the end, away from the knuckle bearing, of the first shell is fixedly connected with an end cover. The end, away from the knuckle bearing, of the axial damping piece is fixedly connected with a connecting shaft, one end of the connecting shaft penetrates through the end cover and then is connected with airborne equipment, a first conical spring connected to the axial damping piece in a sleeving mode is arranged between the end of the connecting shaft and the knuckle bearing, and a second conical spring connected to the connecting shaft in a sleeving mode is arranged between the end of the connecting shaft and the end cover. The vibration isolator can resist impact and effectively prevent the vibration isolator from being broken.

This utility model relates to the field of sheet metal technology and discloses a noise-reducing composite aluminum plate, including a substrate and a cover plate. The substrate has grooves and an array of regular hexagonal microgrooves, with the microgrooves filled with viscoelastic damping adhesive to form a vibration dissipation layer. A trapezoidal wave support skeleton is provided in the groove, with honeycomb panels embedded in its troughs and filled with gradient-density sound-insulating cotton. The inner side of the cover plate is connected to the wave crest of the support skeleton through a connecting seat, and the outer surface has gradient-distributed conical through holes. The cavity between the substrate and the cover plate is filled with closed-cell polyurethane foam. This composite aluminum plate achieves efficient suppression of broadband noise and dissipation of vibration energy through a multi-level synergistic mechanism of conical hole sound wave guidance, cavity sound absorption, trapezoidal wave Bragg scattering, honeycomb hole multiple reflection, gradient cotton layered absorption, and microgroove shear damping. At the same time, waveform interlocking and interference fit ensure structural sealing and long-term stability.

The invention belongs to the technical field of acoustic sound absorption, and particularly relates to an underwater low-frequency broadband sound absorption superstructure covering layer based on a variable-diameter spiral SMA (Shape Memory Alloy) structure, which comprises a rubber matrix made of a viscoelastic damping rubber material and divided into a plurality of unit areas with the same size, a perforated spiral structure is embedded in each unit area, and a specific distance is kept between every two adjacent perforated spiral structures, so that the periodic metamaterial can be ensured to fully play a role. According to the invention, when sound waves enter the structure, the viscoelastic damping rubber can dissipate part of sound energy, and the rigid spiral structure changes the propagation path of the sound waves in the rubber, so that the sound waves are subjected to waveform transformation and are refracted along the outline of the spiral structure; therefore, the propagation distance and propagation time of sound waves in the rubber are increased, the opportunity of interaction between the sound waves and the rubber is increased, and the absorption efficiency of the rubber on sound wave energy is further improved.