22 results about "Noise reduction coefficient" patented technology

The invention relates to the technical field of functional materials, in particular to a sound-absorbing metal plate and a preparation method and application thereof. According to the sound-absorbing metal plate provided by the invention, the metal panel, the functional inner core and the back plate are adopted, and the core is that the sound-absorbing structure of the functional inner core is utilized, so that the noise reduction coefficient is more than 0.95. Specifically, according to the sound-absorbing metal plate provided by the invention, ethylene-vinyl acetate and polyethylene glycol terephthalate are adopted as basic resin, and the pore structure of the functional inner core is controlled by utilizing the synergistic effect of the foaming agent and the cross-linking agent, so that the pore structure is more beneficial to efficient absorption and reduction of sound reflection. According to the sound-absorbing metal plate, the functional inner core is further arranged between the metal face plate and the back plate, the sound-absorbing function and the structural stability of the functional inner core are further enhanced, and the sound-absorbing metal plate provided by the invention achieves the optimal performance. The sound-absorbing metal plate provided by the invention has the advantages of favorable flame retardancy, favorable safety, decoration and beautification functions and favorable overall effect.

The invention belongs to the field of acoustic materials, and relates to a biomass full-degradable porous sound absorption material and a preparation method thereof. In order to solve the problems of poor low-frequency performance, high energy consumption in the production process, non-degradability and the like of the existing sound absorption material, sisal fibers are used as a framework, gelatinized starch is used as a binder, a cross-scale pore structure with the porosity of 70%-87% is realized by regulating and controlling the ratio of water to starch (the mass ratio is 3: 1-15: 1), and a highly through hierarchical pore network is formed by combining a freeze drying process. Through the design of the thickness (10-50 mm) and the backing cavity (10-50 mm), the low-frequency sound absorption performance is remarkably improved, the noise reduction coefficient reaches up to 0.73, the material has good mechanical performance (the tensile strength is 0.5-2.3 MPa) and heat insulation performance (the heat conductivity coefficient is 0.06-0.105 W / (m.K)), meanwhile, bio-based raw materials (sisal fibers and corn starch) are adopted, complete degradation can be achieved, and the production process is free of pollution. The low-frequency sound absorption bottleneck of a natural fiber material is solved, and the composite material is suitable for the fields of building sound insulation, traffic noise reduction and the like and has high efficiency, environmental protection property and economical efficiency.

The utility model provides a multi-layer stacked impedance silencing plate for a sound barrier, which comprises a sound facing surface, a sound backing surface and a plurality of impedance silencing units arranged between the sound facing surface and the sound backing surface, and each impedance silencing unit is a variable cross-section cavity formed by sequentially extending and penetrating from the sound facing surface to the sound backing surface. A plurality of rows of impedance noise elimination units are arranged on the noise elimination plate, noise is eliminated when passing through the impedance noise elimination units, the purpose of noise elimination and reduction is achieved, and experimental tests prove that the noise reduction coefficient of the impedance noise elimination plate reaches 0.95-1.0. Compared with the prior art, the impedance silencing plate is formed by stacking and combining multiple layers of plates, the manufacturing difficulty of the impedance silencing unit is reduced, the manufacturing efficiency of the impedance silencing plate is greatly improved, and the impedance silencing plate is wide in material source, easy to obtain, low in manufacturing cost, light in product weight, good in mechanical strength and anti-fatigue performance and high in application and popularization value.

The invention relates to the technical field of noise pollution protection, in particular to a composite acoustic material for noise reduction and application of the composite acoustic material in large-scale oil-filled power transformation equipment. The composite acoustic material for noise reduction is composed of four parts, the side facing a sound source serves as a starting point, and the first part is a surface layer material in the direction away from the sound source step by step; the second part material is an acoustic function material; the third part is made of a backboard high-temperature-resistant heat-insulating material; and the fourth part is made of a sound insulation structure material. According to the composite acoustic material for noise reduction, the 100 Hz sound absorption coefficient is larger than 0.3, the noise reduction coefficient is not smaller than 0.75, and the original intention of low frequency, high efficiency and broadband effectiveness is met; the overall thickness is fixedly pressed to be 80 mm, the surface density is smaller than 36 kg / m < 2 >, the acoustic performance can reach that the sound insulation index is larger than 45 dB, the efficient sound insulation requirement on the premise of small thickness and light weight is met, and practical application value is achieved.

The present application belongs to the technical field of sound-absorbing materials, and relates to a low-density sound-absorbing inorganic material and a preparation method thereof.The present application provides a low-density sound-absorbing inorganic material, which is composed of carbon fibers and basalt fibers and has a layered structure.The present application produces a layered structure by regulating the proportion of carbon fibers and basalt fibers and utilizing the linear density difference between the carbon fibers and the basalt fibers.The low-density sound-absorbing inorganic material provided by the present application has good sound-absorbing and noise-reducing performance at medium and low frequencies, and has the advantages of low density, low thermal conductivity and high noise-reducing coefficient.

A magnesium-based fly ash porous sound-absorbing material with a surface hydrophobically modified, and a preparation method thereof are provided. In the preparation method, a basic magnesium sulfate cement is adopted as a cementing agent and a fly ash is adopted as a mineral admixture to prepare a slurry; foaming is conducted through a physical foaming process in a foaming machine to obtain a foam; and the foam is mixed with the slurry, and a resulting mixture is poured and cured, and then subjected to a surface hydrophobic modification through vapor deposition to obtain the sound-absorbing material. The sound-absorbing material has a density of 251 kg / m3 to 306 kg / m3, a noise reduction coefficient (NRC) of 0.65 to 0.7, a compressive strength of 1.8 MPa to 2.2 MPa, and a water contact angle of 129° to 151°.

The invention relates to the field of high polymer material processing, in particular to a waterproof roll with a sound-absorbing function, which comprises a porous sound-absorbing layer, a bonding layer and a waterproof layer which are arranged from top to bottom, the thickness of the porous sound-absorbing layer is 2-5mm, the porosity of the porous sound-absorbing layer is 60-80%, the bonding layer is arranged between the porous sound-absorbing layer and the waterproof layer, and the waterproof layer is arranged between the bonding layer and the waterproof layer. The waterproof layer is a modified asphalt layer or a high-molecular polymer layer, and the porous sound absorption layer and the waterproof layer form a permanent composite structure through the bonding layer; in the invention, firstly, in the aspect of functionality, the special bonding layer is arranged between the porous sound-absorbing layer and the waterproof layer, so that collaborative optimization of acoustic performance and waterproof performance is realized, and test data show that according to the sound-absorbing performance, the average sound-absorbing coefficient of the porous sound-absorbing layer within the frequency band of 125-4000 Hz reaches 0.65 or above due to the gradient pore structure (the porosity is 60-80%, and the pore diameter is 0.1-2 mm) of the porous sound-absorbing layer; the noise reduction coefficient is larger than or equal to 0.70 and is increased by 300% or above compared with a traditional waterproof roll.

The invention discloses a noise reduction control method, noise reduction equipment, a noise reduction headrest, a noise reduction seat and a vehicle. The noise detection device is used for detecting noise around human ears; the position detection device is used for detecting the current human ear position; the displacement control device is electrically connected with the position detection device and the sound production device, and the displacement control device is used for controlling the sound production device to move in the direction close to the human ear according to the current human ear position; the noise reduction controller is electrically connected with the sound production device, the noise detection device and the position detection device, and the noise reduction controller is used for determining a target noise reduction coefficient matched with the current human ear position from multiple pre-stored noise reduction coefficients and controlling the sound production device to produce a secondary sound field according to the target noise reduction coefficient and the noise around the human ear; noise around human ears is at least partially offset. According to the invention, the technical problem of poor noise reduction effect of active noise reduction control is solved.

The invention provides an impedance silencing plate for a sound barrier capable of being combined and stacked in multiple layers, which comprises a sound facing surface, a sound backing surface and a plurality of impedance silencing units arranged between the sound facing surface and the sound backing surface, and each impedance silencing unit is a variable cross-section cavity which sequentially extends and penetrates from the sound facing surface to the sound backing surface. A plurality of rows of impedance noise elimination units are arranged on the noise elimination plate, noise is eliminated when passing through the impedance noise elimination units, the purpose of noise elimination and reduction is achieved, and experimental tests prove that the noise reduction coefficient of the impedance noise elimination plate reaches 0.95-1.0. According to the impedance silencing plate, the multiple layers of plates are stacked and combined into the impedance silencing plate, the manufacturing difficulty of the impedance silencing unit is reduced, the manufacturing efficiency of the impedance silencing plate is greatly improved, and the impedance silencing plate is wide in material source, easy to obtain, low in manufacturing cost, light in product weight, good in mechanical strength and fatigue resistance and high in application and popularization value.

The invention discloses a multi-layer composite noise reduction material used in transformer equipment insulating oil, application and an electric reactor, and belongs to the technical field of composite acoustic materials. The cork rubber insulation board is composed of cork rubber and insulation paper boards arranged at the two ends of the cork rubber. One insulating paper board is arranged on the inner wall of an oil tank of the power transformation equipment, the other insulating paper board is provided with a through hole, and a cavity connected with the through hole is arranged in the cork rubber. The structure of the perforated plate and the cavity is easy to form a Helmholtz resonance sound absorption structure, and the structure has a remarkable absorption effect on long-wavelength low-frequency noise. Therefore, the composite material can still achieve the excellent performance that the 100 Hz sound absorption coefficient is larger than 0.3 and the noise reduction coefficient is not smaller than 0.75 in the severe acoustic environment with high sound velocity and long wavelength in oil, and the bottlenecks that a conventional porous material is poor in sound absorption effect in oil and the design of a resonant cavity is harsh are effectively overcome.

A locking dynamic high NRC acoustic baffle and / or tile and a locking dynamic high NRC ceiling and / or wall system, that includes a single piece of material folded into locking dynamic high NRC acoustic baffles and / or tiles, using locking pieces and locking mechanisms, to quickly and easily install the locking dynamic high NRC acoustic baffle and / or tile onto construction ceiling hangers or onto walls to provide an aesthetically pleasing image, along with a reduction in unwanted noise or room acoustics.

This invention discloses an active noise reduction control method, device, air conditioner, and storage medium for an air conditioner, belonging to the field of air conditioning technology. The method includes: acquiring a noise reduction coefficient from each of multiple designated locations within the air conditioner to other designated locations when the air conditioner is off; collecting real noise data generated at each designated location based on the noise reduction coefficient; performing noise reduction processing on a noise reduction module corresponding to the designated location based on the real noise data; acquiring the noise change rate of the real noise data within a preset time period, and determining whether abnormal noise exists based on the noise change rate; and generating a noise anomaly alert when abnormal noise is detected. The method provided by this invention can be applied to energy-saving air conditioners. By calibrating the noise reduction coefficient and collecting real noise data, targeted noise reduction processing can be achieved, thereby improving the overall noise reduction effect; simultaneously, timely maintenance can be performed by identifying abnormal noise.

The invention discloses a metal sound absorber sound barrier design method and device, equipment, a medium and a product, and relates to the technical field of noise control, and the method comprises the steps: determining a target frequency band based on a target sound source; establishing a thermal viscosity-pressure acoustic coupling simulation model of the sound barrier; establishing a model database; scanning the sound barrier thermal viscosity-pressure acoustic coupling simulation model based on the data of the model database, and establishing a simulation database; comparing the sound absorption coefficient obtained by the simulation database with the sound absorption coefficient obtained by the existing theoretical model, and if a deviation exists, correcting the sound absorption coefficient of the simulation database; the maximum noise reduction coefficient and the maximum maximum effective sound absorption bandwidth in the target frequency band serve as optimization targets, and the optimal design parameters and expected performance of the metal sound absorber sound barrier are obtained. Core parameters such as the double-layer distance, the back cavity depth and the micropore diameter can be flexibly adjusted based on the target vibration frequency band, and it is guaranteed that the performance of the sound absorber is optimal.

The utility model provides an impedance muffling plate which comprises a shell and a muffling component arranged in the shell, the shell is a metal shell or a non-metal shell, the impedance muffling plate is characterized in that the muffling component comprises a base body and a muffling component arranged in the base body, the base body can be made of a soft material or a hard material, and the base body is made of a metal material or a hard material. The sound barrier shell comprises a base body and a silencing assembly, the silencing assembly is inserted into the base body in a penetrating mode, a plurality of silencing units are arranged in the silencing assembly, and the silencing units are variable cross-section silencing cavities penetrating through the silencing assembly. Noise is reduced when passing through the impedance noise elimination unit, the purpose of noise elimination and reduction is achieved, experimental tests prove that the noise reduction coefficient of the impedance noise elimination plate reaches 0.95-1.0, and the impedance noise elimination plate has great application and popularization value.

The utility model discloses an ardealite noise barrier plate, and relates to the technical field of road engineering. A plurality of first concave holes are formed in the surface of the side, close to the road, of the ardealite noise barrier plate at intervals, first micro holes and second micro holes are formed in the ardealite noise barrier plate, and the hole diameter of the first concave holes is larger than that of the first micro holes; and the aperture of the first micropores is larger than that of the second micropores. The first concave holes, the first micropores and the second micropores which are different in aperture are formed, and the aperture of the first micropores is larger than that of the second micropores, so that absorption of low-frequency sound waves can be improved through the first concave holes, absorption of medium-frequency sound waves can be improved through the first micropores, and absorption of high-frequency sound waves can be improved through the second micropores; furthermore, broadband sound absorption is achieved through the multi-stage pore structure, the noise reduction coefficient of the phosphogypsum noise barrier plate is increased, and the sound absorption effect of the phosphogypsum noise barrier plate is improved.

The invention discloses a noise reduction method and system for an elevator machine room, and the method comprises the following steps: S1, collecting a first noise signal waveform of a noise source in each operation stage of an elevator car, extracting a first medium-high frequency component according to the first noise signal waveform, and setting a noise reduction coefficient of each operation stage of the elevator car; s2, acquiring distances between a plurality of loudspeakers and the noise source, wherein the plurality of loudspeakers are arranged around the noise source; s3, according to the noise signal waveform, the noise reduction coefficient and the distance, the sound output waveform of the loudspeaker in each operation stage of the elevator car is calculated; and S4, transmitting the sound output waveform to each loudspeaker so as to enable the output sound output waveform to carry out noise reduction on the noise source. The sound waveform is output through the combination of the distance between the loudspeaker and the noise source, the noise reduction coefficients of the noise source in different stages and the first noise signal waveform, and an excellent noise reduction effect is obtained.

The invention discloses a foam silicate particle sound absorption material and a preparation method thereof, and belongs to the technical field of sound absorption materials. The sound absorption material comprises the following components in parts by weight: 100 parts of foamed silicate particles, 20-30 parts of organic glue and 3-5 parts of mineral fibers. The foam silicate particle sound absorption material is high in strength, silicate particles are excellent in weather resistance, freeze-thaw resistance and fireproof performance, small holes exist between individual particles of the formed sound absorption material, the foam silicate particles are of a porous structure, the viscous internal friction, heat conduction and relaxation effects of the sound absorption material are further improved, and the sound absorption material has a good sound absorption effect. The sound absorption effect can be further improved, the noise reduction coefficient NRC can stably reach 0.75 or above, the noise reduction coefficient NRC can reach 0.80 or above through process matching, and the outdoor acoustic sound absorption material is a high-quality outdoor acoustic sound absorption material superior to sound absorption materials in the market.

The utility model relates to an under-vehicle sound absorption and noise reduction structure of a railway vehicle, and belongs to sound absorption and noise reduction structures for railway vehicles. The metal fiber acoustic board is adhered to the periphery of the metal frame and is fixedly connected with the metal frame through rivets I, the metal fiber acoustic board and the metal frame are fixedly connected with the supporting and fixing plate through rivets II, the porous acoustic material is positioned above the high-temperature-resistant aerogel, and the porous acoustic material and the high-temperature-resistant aerogel are adhered to the upper part of the metal fiber acoustic board after being subjected to six-surface wrapping by aluminum foil. The sound absorption plate has the advantages that the structure is novel, the sound absorption effect is good through experimental tests, and the noise reduction coefficient of the whole structure can reach 0.5 or above through tests; the sound absorption structure is additionally arranged below the aluminum profile of the vehicle body chassis, so that the reverberation noise of wheel rails in a bogie area can be reduced; the sound absorption structure is high in material integration, high in installation reliability, resistant to high temperature and high in weather resistance.

The utility model relates to the technical field of indoor sound absorption, and discloses an indoor sound-absorbing coating which comprises a base body, a leveling layer is fixedly arranged at the right end of the base body, a first sound-absorbing putty coating is fixedly arranged at the right end of the leveling layer, a second sound-absorbing putty coating is fixedly arranged at the right end of the first sound-absorbing putty coating, and the second sound-absorbing putty coating is fixedly arranged at the right end of the second sound-absorbing putty coating. A sound-absorbing latex paint coating is fixedly arranged at the right end of the second sound-absorbing putty coating, and glass beads are fixedly arranged in the second sound-absorbing putty coating and the sound-absorbing latex paint coating. The indoor sound-absorbing coating has better sound-absorbing capacity, the noise reduction coefficient (NRC) can reach 0.33, and the hollow glass beads are very light in weight, so that the weight of sound-absorbing putty and sound-absorbing emulsion paint is reduced, the indoor sound-absorbing coating can effectively work for a long time under severe working conditions, the labor intensity is reduced, the construction is more convenient and quicker, the cost is greatly reduced, and the indoor sound-absorbing coating is suitable for popularization and application. And the device has relatively high practicability and good market popularization prospects.

This invention discloses a method for testing the noise reduction coefficient of a sound barrier material, comprising the following steps: placing a plate-shaped test specimen made of the noise reduction material into a reverberation chamber; measuring the sound absorption coefficient α at different frequency bands. s A sound absorption coefficient curve was plotted to determine the maximum sound absorption coefficient α of the noise reduction material. max Determine half of the maximum sound absorption coefficient α based on the sound absorption coefficient curve. max The minimum frequency f corresponding to / 2 min and maximum frequency f max According to f min and f max Determine the frequency band Δf = [f min ,f max According to the traffic noise frequency band Δf T And determine the traffic noise bandwidth Card(Δf) T Determine the effective sound absorption frequency band of the material Δf∩Δf T And determine the effective sound absorption bandwidth Card(Δf∩Δf) T This method allows for the determination of the noise reduction coefficient ε of the material in traffic noise applications. The method for testing the noise reduction coefficient of sound barrier materials in this invention has advantages such as the ability to analyze and evaluate the noise reduction performance of sound barriers through noise reduction coefficient evaluation indicators, and accurately reflecting the sound absorption characteristics and effects of the materials.

The invention relates to collagen nanofiber and lignin composite sponge with an aperture-adjustable layered porous structure, preparation of the collagen nanofiber and lignin composite sponge and application of the collagen nanofiber and lignin composite sponge as a sound absorption material, and belongs to the technical field of noise pollution treatment. The main raw materials of the sound-absorbing sponge are collagen and lignin, collagen nanofiber sponge is used as a framework, and after lignin is doped, the composite sound-absorbing sponge (CLS) with a multi-stage layered pore structure with a loose upper layer and a compact lower layer is formed. Based on the structure, the material shows high porosity (gt; compared with the prior art, the material provided by the invention has the advantages that the material has excellent low-frequency sound absorption performance (the sound absorption coefficient in the frequency range of 2000-6300Hz exceeds 0.9), light weight (10mg / cm < 3 >) and wide-frequency range sound absorption characteristic (the sound absorption coefficient in the frequency range of 2000-6300Hz exceeds 0.9), and meanwhile, the material has extremely excellent low-frequency sound absorption performance, and the noise reduction coefficient NRC of a sample under the thickness of 30mm reaches 0.64 and is far better than that of a natural sound absorption material and a commercial acoustic material which are reported at present.