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33 results about "Impedance tube" patented technology
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Acoustic absorbent high-temperature sound absorption performance test apparatus
InactiveCN101216461AMeet the temperature requirementsAccurate temperature measurementAnalysing solids using sonic/ultrasonic/infrasonic wavesAudio power amplifierSound sources
The invention discloses a high-temperature sound absorption performance test device of a sound absorption material, comprising an impedance tube, a test piece cylinder disposed on one end of the impedance tube for arranging a test piece, a sound source arranged on the other end of the impedance tube, and microphones disposed on the inner wall of the impedance tube close to the test piece cylinder, wherein the microphones are connected with a computer through a spectrum analyzer and the sound source is connected with a signal generator through an amplifier. The invention is characterized in that a majority of the impedance tube is disposed in a heating furnace in the axial direction from the test piece cylinder; a small part of the impedance tube from the end connected with the sound source is disposed in a cooling device in the axial direction; a heat-insulation plate is disposed on the end of the furnace close to the cooling device; the other end of the furnace includes the test piece cylinder and can divide the furnace into two sections through a connector; a plurality of microphone jacks are provided on the middle section of the furnace; the microphones are disposed on the inner wall of the impedance tube through the jacks; a furnace chamber is arranged in the furnace; a heater is disposed in the furnace chamber; and a temperature controller with a temperature measuring thermocouple connected with the heater is disposed in the vicinity of the test piece.
Owner:XI AN JIAOTONG UNIV
Device for testing sound absorption performance of porous metal material under variable parameter temperature field
InactiveCN101696955AAnalysing solids using sonic/ultrasonic/infrasonic wavesData acquisitionEngineering
The invention discloses a device for testing sound absorption performance of a porous metal material under a variable parameter temperature field. The testing device is used for testing sound absorption coefficients of the material under the variable parameter temperature field by using a specially designed structural device and a temperature control system as cores by means of transfer function method principle. The parameter change of environmental temperature required by a test piece can be realized by adjusting an electric heating temperature control system with the assistance of reasonable collocation of a water cooling system, the environmental temperature filed of the test piece of the tested material can be adjusted in a range of between room temperature and 600 DEG C, and the axial temperature gradient inside the test piece can be adjusted in a range of between 0 and 300 DEG C. The temperature evenness of each point on an inner section of an impedance tube is ensured so that the plane wave generated by a loudspeaker does not produce distortion during transmission; and the change of sound pressure signals in the impedance tube is measured by a high-temperature microphone, and the test data are acquired and processed by a data acquisition device and a microcomputer so as to obtain the sound absorption coefficients of the tested material. The testing frequency range of the device is related to the parameters of the impedance tube.
Owner:XI AN JIAOTONG UNIV
Prediction apparatus for sound absorption and insulation performance of multilayer material and method
InactiveCN104535647AEasy to implementEasy to operateAnalysing solids using sonic/ultrasonic/infrasonic wavesTransfer function matrixNoise optimization
A prediction apparatus for sound absorption and insulation performance of a multilayer material and a method are disclosed and relate to the field of testing of sound absorption and insulation performance of materials. The apparatus comprises an impedance tube with a built-in to-be tested single-layer material, a microphone group, a power amplifier, a data acquisition device, a computer and a loudspeaker. The method comprises: firstly testing the sound absorption and insulation performance of a single-layer material; testing the transfer function matrixes of other single-layer materials, and storing in a database; and utilizing the transfer function matrixes of the single-layer materials to calculate the sound absorption and insulation performance of the multi-layer material. According to the technical scheme, a four pole network theory is firstly utilized for testing the transfer function of the single-layer materials, and then the transfer function matrixes of the single-layer materials are utilized for directly obtaining the sound absorption coefficient and the transmission loss of the multi-layer material. The method is easy to realize and convenient to operate, also is high in testing precision, makes up insufficiency of impedance tube testing, and is widely applicable to noise optimization control of multiple fields.
Owner:BRILLIANCE AUTO
Calibration device and calibration method for equivalent self noise acceleration spectrum level of low-noise vector hydrophone
InactiveCN106124025AReduce background noiseLow test frequencyWave based measurement systemsVibration measurement in fluidLow noiseTwo-vector
The invention provides a calibration device and a calibration method for the equivalent self-noise acceleration spectrum level of a low-noise vector hydrophone. It is mainly composed of underwater acoustic tube, vacuum tube, electromagnetic shielding tube, vibration-damping base and upper cover. The noise self-spectrum measured by each vector hydrophone includes the self-noise spectrum and the environmental background noise spectrum, and the cross-correlation calculation of the noise signals of the two vector hydrophones can obtain the environmental background noise spectrum, and then through the known vector hydrophone The transfer function of the earphone can be calculated to obtain the equivalent self-noise acceleration spectrum level of the respective vector hydrophones. The present invention effectively reduces external vibration, electric, electromagnetic and acoustic interference, makes the background noise of the test environment extremely low, and thus better satisfies the calibration accuracy of the equivalent self-noise acceleration spectrum level parameters of the low-noise vector hydrophone It improves the evaluation effectiveness of the self-noise level of the low-noise vector hydrophone, and ensures the engineering application quality of the low-noise vector hydrophone.
Owner:HARBIN ENG UNIV
Measuring system for material normal direction incidence acoustical absorption coefficient and acoustic impedance
InactiveCN103675097AEasy to measureHigh measurement accuracyAnalysing solids using sonic/ultrasonic/infrasonic wavesImpedenceStanding wave ratioSound pressure
The invention relates to a measuring system for material normal direction incidence acoustical absorption coefficient and acoustic impedance. The measuring system comprises a signal transmitter module, an impedance tube, a signal acquisition module, a signal processing module, a signal display module and a report generation module, wherein the signal transmitter module, the impedance tube and the signal acquisition module are connected in sequence, the signal processing module is respectively connected with the signal acquisition module, the signal display module and the report generation module, the signal transmitter module sends out single frequency sinusoidal acoustical signals to the impedance tube, the signal acquisition module acquires the acoustic pressure signal in the impedance tube in real time, and transmits to the signal processing module, the signal processing module displays the received real time acoustic pressure signal through the signal display module, the material normal direction incidence acoustical absorption coefficient and acoustic impedance are calculated through the adoption of a standing wave ratio method, finally the calculated result is generated through the report generation module, and a testing report is stored. Compared with the prior art, the measuring system has the advantages that the measuring process is straightforward, and the measuring accuracy and efficiency are high.
Owner:TONGJI UNIV +1
Material sampler for detecting acoustical material
InactiveCN101303275AEnsure consistencySimple structureAnalysing solids using sonic/ultrasonic/infrasonic wavesWithdrawing sample devicesEngineeringImpedance tube
The invention relates to a material sampler for acoustic material detection, which is composed of a stander, a hydraulic jack, a guide pillar, a balancing plate, a spring, a cutting tool and a backing plate. The guide pillar is vertically and fixedly connected between the upper nog and the lower nog of the stander; the balancing plate is sleeved on the guide pillar; the spring is arranged on the guide pillar under the balancing plate; the hydraulic jack is fixedly arranged on the upper nog, the lower end of the jack being pressed on the balancing plate; the cutting tool, which is tubular, is connected under the balancing plate, the inner diameter of the cutting tool being equal to the inner diameter of the impedance tube of the material to be measured; and the backing plate is arranged on the lower nog. The material sampler can insure the conformity of the inner diameter of the material sample piece and the inner diameter of the impedance tube, the smoothness of the section and the conformity of the sample pieces so as to insure the accuracy of the detection for the performance parameters of the material, thereby reducing test cost and shortening time on testing.
Owner:CHONGQING CHANGAN AUTOMOBILE CO LTD
Method of using dual-port measurement system to measure acoustic impedance
ActiveUS20160077056A1Broaden applicationAnalysing solids using sonic/ultrasonic/infrasonic wavesSound sourcesTest object
A method of using a dual-port measurement system to measure acoustic impedance is used to measure an acoustic impedance Z of a tested object. The tested object includes an input end and an output end opposite to the input end. The dual-port measurement system comprises a first impedance tube and a second impedance tube. The first impedance tube includes a first inlet where a plane wave of a sound source is input, and a first outlet connected with the input end. The second impedance tube includes a second inlet connected with the output end, and a second outlet where the plane wave is output. The method uses the dual-port measurement system and a two-boundary method to obtain the acoustic impedances Z, whereby the dual-port measurement system is conveniently applied to various fields, such as the design of earphones, muffler tubes, sound absorption materials, and artificial ears.
Owner:NATIONAL TSING HUA UNIVERSITY
Correction method and device for combined sound source noise signal
ActiveCN109916609AMachine part testingSubsonic/sonic/ultrasonic wave measurementDigital signal processingSound sources
The invention belongs to the technical field of digital signal processing, and discloses a correction method and device for a combined sound source noise signal. The method comprises the following steps: acoustic impedance of a transition connection tube is measured through an impedance tube; a noise signal of a combined sound source system is corrected according to a transfer matrix of the transition connection tube; and wherein the combined sound source system comprises a low frequency loudspeaker and an intermediate frequency loudspeaker. The device includes the combined sound source system, the transition connection tube and the impedance tube; and the combined sound source system is vertically disposed on the impedance tube through the transition connection tube. The method and the device solve the problem that a working frequency range of the noise signal of an existing muffler transmission loss test bench cannot cover an entire test frequency band, and can output the noise signal with a wide frequency band, a high sound pressure level and stable fluctuation.
Owner:WUHAN UNIV OF TECH
Research method for conducting low-frequency noise processing by using COMSOL and resonant cavity models
ActiveCN108344803ALow costAchieve specific absorptionAnalysing solids using sonic/ultrasonic/infrasonic wavesPeak valueStudy methods
The invention relates to a research method for conducting low-frequency noise processing by using COMSOL and resonant cavity models. The method includes the steps that firstly, resonant cavity modelsof different specifications are made; secondly, first detection groups are placed in B&K type 4206 impedance tubes respectively for sound reduction index testing, and second detection groups are placed in B&K type 4206 impedance tubes respectively for sound reduction index testing; thirdly, theoretical simulation of resonant cavity sound absorption is conducted by using COMSOL software until theoretical data fitted by the COMSOL software is basically consistent with experimental data in the second step; fourthly, expansion simulation of resonant cavity sound absorption continues to be conducted through a control variable method by using the COMSOL software, and finally an influence curve of film thickness and diameter on the sound absorption effect is determined. According to the film typeresonant cavity with adjustable parameters, the absorption frequency and absorption coefficient of the peak value are adjusted by changing the size of the models and the thickness of elastic films, theoretical simulation is conducted by using the COMSOL software, and specific absorption at a specific frequency is realized with the least space, the minimum material consumption and the lowest cost.
Owner:CHONGQING UNIV
Improvement method for low noise structure and sound absorbing structure of indoor substation
ActiveCN110415951AOptimize layoutImprove sound-absorbing structureTransformers/inductances noise dampingInductances/transformers/magnets manufactureAuditory radiationLow noise
The present invention relates to an improvement method for a low noise structure and a sound absorbing structure of an indoor substation. The method visualizes and quantifies an external sound field of a power transformer through acoustic radiation characteristics analysis, combines acoustic radiation characteristics of the power transformer with feedback information between design departments toimprove and optimize an overall layout and the sound absorbing structure of the indoor substation, to reduce sound pressure level at the boundary of a noise sensitive area. Optimization of the overalllayout of the indoor substation includes adjusting position of a transformer vault away from the noise sensitive area, reducing height of a clearstory and changing orientation of the clearstory; Improvements of the sound absorbing structure include increasing depth of a cavity of the sound absorbing structure, attaching a metal film to inside of a foam metal sound absorbing panel, and changing position of some sound absorbing material. The method analyzes the acoustic radiation characteristics through impedance tube comparison test and establishing a 3D multiphysics coupling model. The improved sound absorbing structure can effectively improve overall sound absorption effect and reduce sound radiation level of the substation.
Owner:WUHAN UNIV
Method for carrying out low-frequency noise environmental governance by utilizing super sound absorber
ActiveCN108363872AAchieve specific absorptionSubsonic/sonic/ultrasonic wave measurementDesign optimisation/simulationResonant cavityEngineering
The invention relates to a method for carrying out low-frequency noise environmental governance by utilizing a super sound absorber. The method comprises the following steps of: 1, measuring a noise frequency of a low-frequency noise source; 2, determining a height of the super sound absorber according to a space distance between a cover of the low-frequency noise source and the low-frequency noise source; 3, manufacturing super sound absorber models in different specifications; 4, respectively putting a first detection group and a second detection group into a B&K type 4206 impedance tube tocarry out sound reduction index test; 5, carrying out theoretical simulation on resonant cavity sound absorption by utilizing COMSOL software until theoretical data fit by the COMSOL software is basically consistent with experimental data in the step 4; 6, carrying out extended simulation on the resonant cavity sound absorption by adoption of a control variable method by utilizing the COMSOL software and finally determining a film thickness and a diameter; and 7, manufacturing a plurality of super sound absorbers and fixed the bottoms of the super sound absorbers on the inner wall of the coverof the low-frequency noise source. According to the method, specificity absorption at specific frequencies is realized via minimum space and material and lowest cost.
Owner:CHONGQING UNIV
Backing-independent type acoustic impedance test method for acoustic coating
The invention discloses a backing-independent type acoustic impedance test method for an acoustic coating. An acoustic coating sample is placed at the intermediate position of the tube body of a water-filled impedance tube, and a liquid column of a certain height is ensured on both the upper surface and the lower surface of the acoustic coating sample. One end of the tube cavity of the water-filled impedance tube is internally provided with a projecting transducer. Two hydrophones are arranged in the liquid columns on the upper surface and the lower surface of the acoustic coating sample, respectively. The four hydrophones are respectively connected with a data acquisition instrument. The data acquisition instrument is connected with a measurement control computer. The projecting transducer is driven to launch a stabilized broadband white-noise signal. The data acquisition instrument acquires the acoustic pressures of the hydrophones at the same time and stores the acquired acoustic pressures as a data file. The height of the upper liquid column is changed, and then the data of the acoustic pressures are measured and stored again. After that, the stored data of the acoustic pressures are read, and then the input acoustic impedance and the transmission acoustic impedance of the acoustic coating sample are calculated according to a corresponding equation. According to the technical scheme of the invention, the low-and medium-frequency test accuracy is ensured independent of a backing. Meanwhile, the backing can be re-stuck without taking out the sample. Therefore, the measurement process is simplified, and the measurement efficiency is improved.
Owner:中国船舶重工集团公司第七〇二研究所
Camera module signal wiring mode
InactiveCN104270883AReduce connectionsStable jobTelevision system detailsCircuit optical detailsHigh rateInterference resistance
The invention discloses a camera module signal wiring mode. The camera module signal wiring mode is implemented in a camera module signal wire wring structure. The signal wire wiring structure comprises a substrate body, optical sensors and a plurality of components, wherein the substrate body is provided with a connection wire PAD, the optical sensors are located on the obverse of the substrate body, and the components are distributed on the obverse of the substrate body and located on the outer sides of the optical sensors. The signal wiring mode comprises the following steps that (1) a signal performs bypass parallel wiring; (2) smoothing is performed on the signal. Under the condition of limited design space, through the wiring mode of data signal wires in the optical sensors, the wiring lengths of a differential signal pair are matched, the transmission rates are equal, and better interference resistance is achieved. Because of the higher rates, the simpler signal wire connection and better differential impedance control over the signal by the wires, a camera module has the advantages of being stable in working, high in interference resistance and the like.
Owner:江西意科斯光电科技有限公司
Acoustic measurement system with tunable radial magnetic field loading device
InactiveCN110501420ASimple and fast operationChange performanceAnalysing solids using sonic/ultrasonic/infrasonic wavesElectrical impedanceAcoustics
The invention relates to the technical field of sound insulation testing of an impedance tube, in particular to an acoustic measurement system with a tunable radial magnetic field loading device. Theacoustic measurement system comprises an impedance tube measurement system and a tunable radial magnetic field loading device. The tunable radial magnetic field loading device is composed of a circular-ring-shaped frame, a support frame, a coil unit, a lock nut, an insulating washer, and a DC power supply and is arranged outside the impedance tube measurement system; the magnetic field plane generated by the tunable radial magnetic field loading device is perpendicular to the impedance tube axis of the impedance tube measurement system, so that the circular-ring-shaped frame of the tunable radial magnetic field loading device and the impedance tube are in a concentric manner. Since the distance between the end of the coil unit and the outer surface of the impedance tube is controlled within 2 mm, the radial magnetic field is applied to a tested piece; and the tunable radial magnetic field loading device can move axially along the impedance tube, so that the radial magnetic field can beloaded at any position of the impedance tube.
Owner:JIANGSU UNIV
Research method of low frequency noise processing using comsol and resonant cavity model
ActiveCN108344803BLow costAchieve specific absorptionAnalysing solids using sonic/ultrasonic/infrasonic wavesResonant cavityNoise
The invention relates to a research method for conducting low-frequency noise processing by using COMSOL and resonant cavity models. The method includes the steps that firstly, resonant cavity modelsof different specifications are made; secondly, first detection groups are placed in B&K type 4206 impedance tubes respectively for sound reduction index testing, and second detection groups are placed in B&K type 4206 impedance tubes respectively for sound reduction index testing; thirdly, theoretical simulation of resonant cavity sound absorption is conducted by using COMSOL software until theoretical data fitted by the COMSOL software is basically consistent with experimental data in the second step; fourthly, expansion simulation of resonant cavity sound absorption continues to be conducted through a control variable method by using the COMSOL software, and finally an influence curve of film thickness and diameter on the sound absorption effect is determined. According to the film typeresonant cavity with adjustable parameters, the absorption frequency and absorption coefficient of the peak value are adjusted by changing the size of the models and the thickness of elastic films, theoretical simulation is conducted by using the COMSOL software, and specific absorption at a specific frequency is realized with the least space, the minimum material consumption and the lowest cost.
Owner:CHONGQING UNIV
Impedance tube having a machined union
A combustion system can include: a liner defining a combustion chamber; a casing covering the combustion chamber; a first tube disposed in the liner; a machined union disposed inside the casing and connected to the first tube; a second tube passing through the casing and connected to the machined union; a sensor housing disposed outside the casing and connected to the second tube; and an infinite tube connected to the sensor housing.
Owner:DOOSAN HEAVY IND & CONSTR CO LTD
Acoustic coefficient testing device and testing method
ActiveCN113740438BImprove test efficiencyAnalysing solids using sonic/ultrasonic/infrasonic wavesEngineeringSound wave
The application provides an acoustic coefficient test device and a test method. The acoustic coefficient test device includes a speaker, an impedance tube and a sensor assembly. The impedance tube includes at least three sound guide tubes that are bent and connected in sequence and communicated with each other. The first sound guide tube The head end is docked with the speaker, and the connection between two adjacent sound guide pipes is used to install the material to be tested. The material to be tested can reflect the sound wave signal in the previous sound guide pipe to the next sound guide pipe. The sensor assembly includes at least three A group of main body sensors, each group of main body sensors are respectively installed in each sound guide pipe, and include a plurality of main body sensors arranged side by side along the length direction of the sound guide pipe, each main body sensor is used to collect the sound waves in each sound guide pipe Signal. The impedance tube includes at least three sound guide tubes that are bent and connected in sequence and communicated with each other. Materials to be tested are provided at the joints of two adjacent sound guide tubes, so that the acoustic test can be performed on multiple materials to be tested, and the test efficiency is improved. .
Owner:BYD CO LTD +1
Method and device for correcting combined sound source noise signal
ActiveCN109916609BMachine part testingSubsonic/sonic/ultrasonic wave measurementDigital signal processingSound sources
Owner:WUHAN UNIV OF TECH
Adjustable test piece cylinder rear plate
PendingCN111735876ASimple structureEasy to installAnalysing solids using sonic/ultrasonic/infrasonic wavesAir tightnessPhysics
The invention provides an adjustable test piece cylinder rear plate, and particularly relates to the field of feed production devices. The adjustable test piece cylinder rear plate comprises a bottomplate and a cylindrical impedance tube; the bottom plate is provided with a sealing column; the two sides of the sealing column are provided with a first clamping plate and a second clamping plate respectively, and the end parts of the first clamping plate and the second clamping plate are connected with the bottom plate; the sealing column is embedded into the impedance tube; and the side walls of the impedance tube is located between the first clamping plate and the sealing column and between the second clamping plate and the sealing column. According to the invention, the problems of air tightness and fixation caused by axially pushing the test piece cylinder rear plate can be solved.
Owner:南京光声超构材料研究院有限公司 +1
PCB impedance control method, device and equipment and readable storage medium
PendingCN113286444AAvoid issues where signal integrity is not guaranteedNon-metallic protective coating applicationImpedance matchingLight painting
The invention discloses a PCB impedance control method. The method comprises the steps: adding a region mark corresponding to a signal line region of a PCB light painting file in the PCB light painting file after the design of the PCB light painting file is completed, obtaining a marked PCB light painting file, and then transmitting the marked PCB light painting file and an impedance control requirement of the PCB light painting file to a board factory. Therefore, when the board factory carries out PCB resistance welding processing, distinguishing processing can be carried out according to the region mark and impedance control requirement, and the problem that the signal integrity cannot be guaranteed due to unqualified impedance matching caused by uneven resistance welding thickness of a signal line area due to the fact that the board factory processes the PCB according to a unified standard is solved. The invention further discloses a PCB impedance control device and equipment and a readable storage medium, which have the above beneficial effects.
Owner:LANGCHAO ELECTRONIC INFORMATION IND CO LTD
Axial magnetic field loading device with adjustable strength
PendingCN113311068ASolve the leakEasy to assemble and disassembleAnalysing solids using sonic/ultrasonic/infrasonic wavesCopper wireEngineering
The invention relates to an impedance tube sound insulation measurement technology, in particular to an axial magnetic field loading device with adjustable strength. The device is composed of a cylindrical pipe, a heat dissipation baffle, an enameled copper wire, a locking device, a piston rod, an adjustable lifting device and a direct-current power supply. The axial magnetic field loading device with the adjustable strength is connected through a tightening device, the cylindrical pipe and the impedance pipe are tightly connected, the problem of sound leakage in an impedance pipe measuring system is solved, and disassembly and assembly are convenient and fast. The axial magnetic field loading device with adjustable strength realizes loading of a uniform magnetic field, and the magnetic field strength is quantitatively controlled through input current. The heat dissipation baffle solves the problem that the sound insulation measurement precision is influenced because electric heat generated in a long-time experiment cannot be dissipated. An external adjustable uniform magnetic field test environment can be provided on the premise of ensuring the measurement precision.
Owner:JIANGSU UNIV
A testing method for acoustic impedance of acoustic coverings independent of backing
Owner:中国船舶重工集团公司第七〇二研究所
Device for testing sound absorption performance of porous metal material under variable parameter temperature field
InactiveCN101696955BAnalysing solids using sonic/ultrasonic/infrasonic wavesData acquisitionEngineering
Owner:XI AN JIAOTONG UNIV
Acoustic impedance tube
PendingCN111487324AImprove portabilityEasy to adjustAnalysing solids using sonic/ultrasonic/infrasonic wavesEngineeringLoudspeaker
The invention provides an acoustic impedance tube. The tube comprises an impedance tube, a positioning disc and a telescopic strut. The impedance tube comprises a fixed sleeve and a telescopic sleeve;a loudspeaker is arranged at the top of the telescopic sleeve; and the bottom of the telescopic sleeve is inserted into the top of the fixed sleeve, an acoustic measurement sensor is arranged on a wall of the fixed sleeve, the positioning disc is installed at the bottom of the fixed sleeve and used for fixing the acoustic impedance tube to the surface of a measured material, and a top end of thetelescopic strut is connected with the loudspeaker through a support and used for adjusting an overall height of the impedance tube. The two telescopic devices in the acoustic impedance tube can facilitate a user to adjust the lengths of different devices so as to correspond to to-be-measured materials with different frequencies, and portability of the acoustic impedance tube is improved.
Owner:STATE GRID HUBEI ELECTRIC POWER RES INST +2
A coupon generation method and system for testing high-speed signal impedance
ActiveCN108834315BImprove the efficiency of designing couponsResolution timeCircuit artworks manufactureComputer designed circuitsDifferential lineReliability engineering
Owner:ZHENGZHOU YUNHAI INFORMATION TECH CO LTD
Acoustic absorbent high-temperature sound absorption performance test apparatus
InactiveCN100561216CMeet the temperature requirementsAccurate temperature measurementAnalysing solids using sonic/ultrasonic/infrasonic wavesSound sourcesAudio power amplifier
The invention discloses a high-temperature sound-absorbing performance testing device for sound-absorbing materials, which comprises an impedance tube. A microphone is provided; the microphone is connected to a computer through a spectrum analyzer; the sound source is connected to a signal generator through an amplifier; it is characterized in that most of the impedance tube axially from the test piece cylinder is placed in a heating furnace body, and the impedance tube The small part from the end connected to the sound source in the axial direction is placed in a cooling device; the end of the furnace body close to the cooling device is provided with a heat shield, and the other end of the furnace body contains the test piece tube and the furnace body can be disassembled through the connecting piece It is divided into two parts; several microphone jacks are set in the middle of the furnace body, and the microphones are placed on the inner wall of the impedance tube through the jacks; a furnace is set in the furnace body, a heating body is set in the furnace, and a temperature measuring thermocouple is installed near the test piece to connect Temperature controller for controlling the heating body.
Owner:XI AN JIAOTONG UNIV
An improvement method for low-noise structure and sound-absorbing structure of indoor substation
ActiveCN110415951BEfficient Noise SuppressionImprove sound absorption performanceGeometric CADTransformers/inductances noise dampingLow noiseTransformer
The invention relates to an improvement method for low-noise structure and sound-absorbing structure of an indoor substation. Visualization and quantitative analysis are performed on the external sound field of a power transformer through the analysis of the sound radiation characteristics, and the indoor The overall layout and sound-absorbing structure of the substation are improved and optimized to reduce the sound pressure level at the boundaries of noise-sensitive areas. The optimization of the overall layout of the indoor substation includes adjusting the position of the transformer room to keep it away from the noise-sensitive area, reducing the height of the ventilation window and changing the orientation of the ventilation window, etc.; the improvement of the sound-absorbing structure includes increasing the cavity depth of the sound-absorbing structure, Attach a layer of metal film to the inner side of the metal sound-absorbing panel and change the position of some sound-absorbing materials. By comparing the actual measurement with impedance tubes and establishing a 3D multi-physics field coupling model to analyze the sound radiation characteristics, the improved sound-absorbing structure can effectively improve the overall sound-absorbing effect and reduce the sound radiation level of the substation.
Owner:WUHAN UNIV
Acoustic impedance tube acoustic performance test auxiliary test device
PendingCN114878699ASolving Combinatorial Testing ProblemsGuaranteed parallelMaterial analysis using sonic/ultrasonic/infrasonic wavesSound sourcesTest sample
The invention aims to provide an acoustic impedance tube acoustic performance test auxiliary test device which comprises a test piece cylinder and a sound source cylinder, one end of the test piece cylinder is connected with the sound source cylinder, the other end of the test piece cylinder is provided with a rear cover, a sound source is arranged in the sound source cylinder, a to-be-tested sample is placed in the test piece cylinder, and a grooved scale is arranged in a storage area of the to-be-tested sample. A thin clamping groove for mounting a fixing needle is formed in the size information position of the grooved scale; and a side square cover is arranged on the side of the test piece cylinder in the storage area of the to-be-tested sample. The test piece cylinder is provided with the side square cover, so that a to-be-tested sample can be conveniently and quickly taken out or placed; the problem of combined testing of various materials and an air layer can be well solved by using the combination of the fixing needle and the grooved scale, and the thickness and the relative position of a sample to be tested can be accurately determined; for a thin material, an experimental sample can be ensured to be simultaneously vertical to a pipe wall and a horizontal plane, and a to-be-tested sample is ensured to be parallel to a sound source to ensure the accuracy of experimental data; the device has the advantages of safety, reliability, simplicity in operation, novel structure and the like.
Owner:HARBIN ENG UNIV
Impedance tube having a machined union
ActiveUS20190292935A1Continuous combustion chamberEngine fuctionsCombustion systemCombustion chamber
A combustion system can include: a liner defining a combustion chamber; a casing covering the combustion chamber; a first tube disposed in the liner; a machined union disposed inside the casing and connected to the first tube; a second tube passing through the casing and connected to the machined union; a sensor housing disposed outside the casing and connected to the second tube; and an infinite tube connected to the sensor housing.
Owner:DOOSAN HEAVY IND & CONSTR CO LTD
Measuring and calculating method for viscoelasticity dynamic mechanical parameters of damping material
InactiveCN105259255ASimple structureEasy to processAnalysing solids using sonic/ultrasonic/infrasonic wavesViscoelasticityPoisson's ratio
The invention discloses a measuring and calculating method for viscoelasticity dynamic mechanical parameters of a damping material. The measuring and calculating method includes respectively measuring reflection coefficients of a solid damping material covering layer and a damping material covering layer including a cylindrical cavity under the condition of normal incidence in a water-filled impedance tube; obtaining the longitudinal wave velocity of the damping material according to the reflection coefficient of the solid damping material covering layer; obtaining the shear wave velocity of the damping material according to the reflection coefficient of the damping material covering layer including the cylindrical cavity, in combination with eigen equation of wave propagation in a viscoelastic cylindrical tube; and obtaining viscoelasticity dynamic mechanical parameters such as elasticity modulus, shear modulus and Poisson's ratio according to constitutive relation. The covering layer sample for measuring viscoelasticity dynamic mechanical parameters of the damping material is simple in structure and easy to produce, and meanwhile the sample can accomplish acoustic characteristic measuring so that the cost is reduced; the limitation that the vibration beam method only has low frequency measuring results is overcome, effective measuring frequency bands of viscoelasticity dynamic mechanical parameters are effectively increased, and synchronization of parameter measurement and mechanism study is achieved.
Owner:GUIZHOU UNIV
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