CN114200004A - Method and system for testing high-frequency-band sound absorption coefficient, electronic equipment and computer-readable storage medium - Google Patents
Method and system for testing high-frequency-band sound absorption coefficient, electronic equipment and computer-readable storage medium Download PDFInfo
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- CN114200004A CN114200004A CN202111442900.8A CN202111442900A CN114200004A CN 114200004 A CN114200004 A CN 114200004A CN 202111442900 A CN202111442900 A CN 202111442900A CN 114200004 A CN114200004 A CN 114200004A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/04—Analysing solids
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/32—Arrangements for suppressing undesired influences, e.g. temperature or pressure variations, compensating for signal noise
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2291/00—Indexing codes associated with group G01N29/00
- G01N2291/02—Indexing codes associated with the analysed material
- G01N2291/023—Solids
- G01N2291/0231—Composite or layered materials
Abstract
The invention claims a method for testing a high-frequency-band sound absorption coefficient by adopting a reverberation room rule, which relates to the technology of testing automobile material noise, and comprises the steps of constructing a reverberation room with a humidity buffer room, arranging a sound insulation door between the reverberation room and the buffer room, arranging a humidity monitoring point in the buffer room, arranging four humidity monitoring points in the reverberation room, distributing the four humidity monitoring points at four corners of a test material, adjusting the humidity of the reverberation room and the humidity of the buffer room, and controlling the humidity difference of the two rooms to be lower than 5%; testing the reverberation time of the empty room state of the reverberation room; testing the reverberation time of the test sample in the reverberation chamber; and determining the sound absorption coefficients before and after the sample is placed in the reverberation chamber, and obtaining the sound absorption coefficient of the material by subtracting the two coefficients. The high-frequency-band sound absorption testing precision is improved.
Description
Technical Field
The invention relates to a noise test technology of an automobile material, in particular to research on test control of a sound absorption coefficient of the automobile material in a high-frequency band.
Background
A silent passenger compartment environment is a basic requirement of a current automobile, and with the rapid development of electric vehicles and intelligent vehicles, a silent and comfortable driving experience is one of important conditions for excellent quality of a trolley. In order to create a silent environment in a vehicle, strict requirements are required for the sound absorption performance of acoustic materials (such as carpets, sound insulation pads, ceiling linings and the like) used by the vehicle, and an indispensable task in the development process is to test the sound absorption coefficient of the acoustic materials, so that the sound absorption performance of the materials is measured according to the sound absorption coefficient.
The method for testing the sound absorption coefficient of the material by using the reverberation chamber method is a method commonly adopted by many host factories, but has a common problem that the test precision of the sound absorption coefficient of a high frequency band above 4000Hz is poor, the deviation of the result of repeated tests of the same material is large, and the technical difficulty is brought to the balance of sound absorption performance and cost.
The method for improving the high-frequency-band sound absorption coefficient test precision by controlling the temperature and humidity of the test environment, improving the test tool, enhancing the sealing of the sound-proof door of the reverberation chamber and the like is developed in the industry, but the effect is not ideal.
Disclosure of Invention
The invention provides a method for improving the test precision of a high-frequency-band sound absorption coefficient, aiming at the problems of large test error and low test precision of a material sound absorption coefficient by adopting a reverberation chamber method in the prior art, and the aim of improving the test precision is mainly fulfilled by additionally arranging a humidity buffer room in an inlet area of a reverberation chamber and increasing the number of humidity monitoring points inside the reverberation chamber.
The technical scheme for solving the technical problems is that a method for testing the high-frequency-band sound absorption coefficient by adopting a reverberation chamber rule is provided, a humidity buffer room is arranged in an inlet area of the reverberation chamber, the reverberation chamber and the buffer room are isolated by a reverberation chamber sound insulation door, a humidity monitoring point is arranged in the buffer room, four humidity monitoring points are arranged in the reverberation chamber and distributed at four corners of a test material, and a humidity adjusting device detects and controls the humidity difference of the two rooms to be lower than 5%; testing the reverberation time T1 of the empty room state of the reverberation room; placing the test sample piece into a reverberation room, closing a sound insulation door, and placing the reverberation time T2 of the test sample piece in the reverberation room; invoking the formula Ti=0.161V/αis (i =1,2) respectively calculating sound absorption coefficients alpha 1 and alpha 2 before and after the sample is placed in the reverberation chamber, and according to a formula alpha=α2-α1Calculating a sound absorption coefficient alpha of the detection sample, wherein V is the volume of the reverberation chamber and alpha1For acoustic absorption coefficient, alpha, before placing the sample2For the sound absorption coefficient after placing the sample, S is the area of the detection material.
Further, the vertical heights of the four monitoring points are 0.5m, 1m, 1.5m and 2m respectively, the arithmetic mean value of the detected humidity of the four monitoring points is calculated to be the humidity value of the reverberation chamber, and the humidity controller ensures that the difference between the humidity of the empty room of the reverberation chamber and the humidity of the room with the sample is lower than 2%. The humidity controller controls the humidity of the empty room of the reverberation room to be kept at 60 percent, and the humidity of the buffer room is 55 to 60 percent.
The invention also provides a system for testing the high-frequency-band sound absorption coefficient by using the reverberation room rule, which comprises the following components: reverberation room, humidity buffering room set up the soundproof door between reverberation room and the humidity buffering room, and the buffering room door is located one side of soundproof door vertical direction, sets up a humidity monitoring point in the buffering room, arranges four humidity monitoring points in the reverberation room, distributes in four corners of test sample spare, apart from four summits 1m distances of test sample spare, and four vertical height of monitoring point are 0.5m, 1m, 1.5m, 2m respectively, and the indoor configuration of reverberation: the device comprises a reverberation time testing device for testing the reverberation time of the empty reverberation chamber and the reverberation chamber with the sample piece, a humidity control device for adjusting and controlling the humidity difference between the reverberation chamber and the buffer room to be lower than 5%, and a calculating unit for calculating and detecting the sound absorption coefficient of the sample piece and calculating the humidity value in the reverberation chamber.
Further, the humidity controller controls the humidity of the empty room of the reverberation room to be kept at 60%, the humidity of the buffer room is 55% -60%, and the difference between the humidity of the empty room of the reverberation room and the humidity of the room with the sample is lower than 2%; the reverberation time testing unit tests the reverberation time T1 of the empty room state of the reverberation chamber, and tests the reverberation time T2 of a test sample piece placed in the reverberation chamber; sound absorption coefficient detection unit calls formula Ti=0.161V/αis (i =1,2) respectively calculating the sound absorption coefficient alpha before and after the sample is placed in the reverberation chamber1And alpha2According to the formula α = α2-α1Calculating a sound absorption coefficient alpha of the detection sample, wherein V is the volume of the reverberation chamber and alpha1For acoustic absorption coefficient, alpha, before placing the sample2For the sound absorption coefficient after placing the sample, S is the area of the detection material.
The present invention also claims an electronic device, including: one or more processors; a memory; one or more application programs stored in the memory and configured to be loaded and executed by the one or more processors to perform the method of testing high band sound absorption coefficients of the present invention
The invention also claims a computer-readable storage medium, on which a computer program is stored which can be loaded and run by a processor to perform the above-described method of testing high frequency band sound absorption coefficients.
Therefore, when the sound insulation door of the reverberation room is frequently opened and closed, because the air humidity on the two sides of the sound insulation door is close, the air humidity in the reverberation room cannot be greatly changed, the difference of the humidity of two states of an empty room and a room with a sample piece is guaranteed to be controlled within 2%, and the purpose of improving the sound absorption test precision of a high-frequency band is finally achieved.
Drawings
FIG. 1 is a schematic diagram of a sample-carrying state of a reverberation chamber;
FIG. 2 is a graph showing the repetitive difference of sound absorption coefficient in a high frequency band;
FIG. 3 is a schematic diagram of a buffer room and a humidity monitoring point design;
FIG. 4 sound absorption coefficient test flow chart;
FIG. 5 is a schematic diagram showing good reproducibility of sound absorption in a high frequency band.
Detailed Description
In order to facilitate understanding of the technical solutions of the present invention, the following further describes embodiments of the present invention with reference to the accompanying drawings and examples.
A large number of experimental researches show that the precision of a high-frequency test result can be obviously influenced by the change of the humidity of the test environment, the smaller the humidity difference between a room with a sample and a room with the sample is during testing, the higher the test precision is, and the conventional requirement of 5% of humidity difference cannot ensure the high-frequency test precision. Through multiple experiments and verification, the problem of poor high-frequency testing precision can be effectively solved by controlling the humidity difference between an empty room and a room with a sample within 2%, and how to ensure that the humidity difference is small in two tests is a key problem. And only one humidity monitoring point is arranged in the reverberation room, so that the detection of the average humidity level of the air in the reverberation room is inaccurate and not representative. In addition, as the sound insulation door of the reverberation room is frequently opened and closed in the test process, the exchange between the reverberation room and the outside air is more, and the change of the air humidity in the reverberation room is caused.
For example: in the schematic diagram of the state of the sample-carrying part of the reverberation room shown in fig. 1, a humidity monitoring point 2 of the reverberation room is arranged in a reverberation room 3, a test material 4 is placed on the ground at the center of the reverberation room, and a sound insulation door 1 is arranged in the reverberation room. And (3) sequentially testing the reverberation time of the empty room state and the room placing sample state in a reverberation room. Testing reverberation time T of empty room state of reverberation room1: the test sample is not placed in the reverberation chamber, the empty room state is kept, and the reverberation time T of the reverberation chamber in the empty room state is tested1(ii) a Putting the test sample into a reverberation chamber, and testing the reverberation time T of the reverberation chamber with the sample state2: the temperature required in the test process is room temperature, and the humidity difference of a room and a room with a sample piece does not exceed 2 percent during the test. According to the reverberation time T, the volume V of the reverberation chamber and the surface area S of the sample material, a Sabin formula is utilized on the basis of the reverberation chamber method: and calculating T = 0.161V/alpha s to obtain the sound absorption coefficient alpha of the material.
According to the conventional operation, the same group of material sample pieces are repeatedly tested for many times, so that the test error is large, and the test precision is not high. Fig. 2 is a schematic diagram showing the repeatability of sound absorption in a high frequency range tested in a reverberation room, wherein the abscissa is a frequency coordinate and the ordinate is a sound absorption coefficient. It is clear from the test result diagram that the sound absorption coefficient is very poor in repeatability in the high frequency range of 5000-.
The invention provides a method for improving the sound absorption high-frequency-band test precision of a test material of a reverberation chamber, which mainly aims to improve the test precision by adding a humidity buffer room in an inlet area of the reverberation chamber and increasing the number of humidity monitoring points inside the reverberation chamber.
Due to the existence of the buffer room, the humidity of the air in the reverberation room can not change greatly in the process of opening the sound insulation door and placing the sample piece, the humidity difference between the reverberation room and the sample piece-carrying room can be further controlled (optimally controlled within 2%), a plurality of monitoring points (4 in the invention) are arranged in the reverberation room to monitor the humidity of the reverberation room, and the arithmetic mean value of the humidity obtained by monitoring by the monitoring points is the humidity of the reverberation room. The buffer room is additionally arranged at the inlet area of the reverberation room, the buffer room and the inlet of the reverberation room are sealed through a sound insulation door, and the area of the buffer room is generally controlled to be about 50% of the area of the reverberation room, so that the humidity difference of the reverberation room in an empty room and the sample carrying piece is controlled within 2%.
Fig. 3 is a schematic diagram of a buffer room and humidity monitoring points, a humidity buffer room 2 is disposed in an inlet area of a reverberation room 1, the reverberation room and the buffer room are isolated by a reverberation room sound insulation door 4, a humidity monitoring point 3 is disposed in the buffer room, four humidity monitoring points are disposed in the reverberation room and distributed at four corners of a test material, a predetermined distance (about 1m distance) is formed between the reverberation room and four vertexes of the test material in a horizontal direction, vertical heights of the four monitoring points are respectively 0.5m, 1m, 1.5m and 2m, (for example, a humidity monitoring point 5 is disposed at a height of 0.5m from the ground in a vertical direction, a humidity monitoring point 6 is disposed at a height of 1m in the vertical direction, a humidity monitoring point 7 is disposed at a height of 1.5m in the vertical direction, and a humidity monitoring point 8.) an arithmetic average of humidity detected by the four monitoring points is regarded as a humidity value of the reverberation room air. And humidity adjusting devices are arranged in the reverberation room and the buffer room to detect and control the room humidity, and the humidity error between the air humidity value in the reverberation room and the humidity monitoring point in the buffer room is ensured to be within 5 percent by comparing the air humidity values of the two rooms and adjusting the humidity through equipment when necessary.
Therefore, even if the air humidity at the two sides of the sound insulation door of the reverberation room is close when the sound insulation door of the reverberation room is frequently opened and closed, the air humidity in the reverberation room cannot be greatly changed, the difference between the humidity of two states of an empty room and a room with a sample piece is controlled within 2 percent, and the purpose of improving the sound absorption test precision of a high-frequency band is finally achieved.
In the testing stage, the temperature is required to be room temperature in the testing process, a testing sample is not placed in the reverberation room, four humidity monitoring points and a buffer room humidity monitoring point which are arranged in the reverberation room monitor the humidity of two rooms in real time, and the humidity of the reverberation room is the arithmetic mean value of the humidity detected by the four detection points. The humidity adjusting device controls the difference of the humidity of the two rooms not to exceed a preset value of 5 percent. Opening a door of the buffer room, putting the sample to be tested in the buffer room, and closing the buffer room;
keeping the empty room state of the reverberation room, and testing the reverberation time T of the empty room state of the reverberation room1；
And opening the sound insulation door, placing the sample piece to be tested into the reverberation chamber, closing the sound insulation door, and testing the reverberation time T2 of the sample piece to be tested in the reverberation chamber.
Calculating the sound absorption coefficient of the sample piece: reverberation time T obtained by testing according to two different states1、T2According to the formula of Sabin Ti=0.161V/αis (i =1,2) respectively calculating sound absorption coefficients alpha 1 and alpha 2 before and after placing the sample piece, wherein V is the volume of the reverberation chamber and alpha1Coefficient of sound absorption, alpha, before placing a sample2After the sample is placed, the sound absorption coefficient is obtained, S is the surface area of the sample to be tested, and the formula is alpha = alpha2-α1And calculating the sound absorption coefficient alpha of the sample piece.
As shown in the sound absorption coefficient test flow chart of fig. 4, the reverberation chamber is maintained as an empty room, the humidity is adjusted to be 60%, the humidity of the outside buffer room is 55% -60%, and then the reverberation time T is tested1(ii) a Then putting the test sample piece into the test room, adjusting the humidity of the reverberation room to be maintained at 60 percent, adjusting the humidity of the buffer room to be maintained at 55 to 60 percent, and continuously testing the reverberation time T2. Based on T1、T2Using the Sabin formula Ti=0.161V/αis (i =1,2) calculating the sound absorption coefficient alpha before and after placing the sample respectively1And alpha2Finally obtaining the sound absorption coefficient alpha = alpha2-α1。
Fig. 5 is a schematic diagram showing the repeatability of high-frequency band sound absorption. As is clear from the figure, the sound absorption coefficient is a curve varying with frequency. The method of the invention is adopted to test the same group of materials for many times, and the sound absorption coefficient curve has good repeatability in the high frequency range of 5000-.
Claims (7)
1. A method for testing a high-frequency-band sound absorption coefficient by adopting a reverberation chamber rule is characterized in that a humidity buffer room is arranged in an inlet area of the reverberation chamber, the reverberation chamber and the buffer room are isolated by a reverberation chamber sound insulation door, a humidity monitoring point is arranged in the buffer room, four humidity monitoring points are arranged in the reverberation chamber and distributed at four corners of a test material, and a humidity controller ensures that the humidity difference between an empty room of the reverberation chamber and a room with a sample piece is lower than 2%; testing the reverberation time T1 of the empty room state of the reverberation room; placing the test sample piece into a reverberation room, closing a sound insulation door, and placing the reverberation time T2 of the test sample piece in the reverberation room; invoking the formula Ti=0.161V/αis (i =1,2) respectively calculating sound absorption coefficients alpha 1 and alpha 2 before and after the sample is placed in the reverberation chamber, and according to the formula alpha = alpha2-α1Calculating a sound absorption coefficient alpha of the detection sample, wherein V is the volume of the reverberation chamber and alpha1For acoustic absorption coefficient, alpha, before placing the sample2For the sound absorption coefficient after placing the sample, S is the area of the detection material.
2. The method of claim 1, wherein the four monitoring points have vertical heights of 0.5m, 1m, 1.5m and 2m, the arithmetic mean of the detected humidities of the four monitoring points is calculated as a humidity value of the reverberation room, the humidity monitoring point in the buffer room detects the humidity of the buffer room, and the humidity adjusting device controls the humidity difference between the reverberation room and the buffer room to be less than 5%.
3. The method of claim 1 or 2, wherein the humidity controller maintains the humidity of the empty room of the reverberation chamber at 60% and the humidity of the buffer room at 55% -60%.
4. A system for testing high-band sound absorption coefficients using the reverberant room law, comprising: reverberation room, humidity buffering room set up the soundproof door between reverberation room and the humidity buffering room, and the buffering room door is located one side of soundproof door vertical direction, sets up a humidity monitoring point in the buffering room, arranges four humidity monitoring points in the reverberation room, distributes in four corners of test sample spare, apart from four summits 1m distances of test sample spare, and four vertical height of monitoring point are 0.5m, 1m, 1.5m, 2m respectively, and the indoor configuration of reverberation: the device comprises a reverberation time testing device for testing the empty reverberation room and the reverberation room with the sample piece, a humidity control device for adjusting and controlling the humidity difference between the reverberation room and the buffer room to be lower than 5%, and a calculating unit for calculating the sound absorption coefficient of the detection sample piece and the humidity value in the reverberation room.
5. The system of claim 4, wherein the humidity controller controls the humidity of the empty room of the reverberation room to be maintained at 60% and the humidity of the buffer room to be 55% -60%, so as to ensure that the difference between the humidity of the empty room of the reverberation room and the humidity of the sample room is less than 2%; the reverberation time testing unit tests the reverberation time T1 of the empty room state of the reverberation chamber, and tests the reverberation time T2 of a test sample piece placed in the reverberation chamber; the calculation unit calls the formula Ti=0.161V/αiS (i =1,2) respectively calculates sound absorption coefficients alpha 1 and alpha 2 before and after the sample is placed in the reverberation chamber, and calculates the sound absorption coefficient alpha of the sample to be detected according to a formula alpha = alpha 2-alpha 1, wherein V is the volume of the reverberation chamber, alpha 1 is the sound absorption coefficient before the sample is placed, alpha 2 is the sound absorption coefficient after the sample is placed, and S is the area of the detection material.
6. An electronic device, comprising: one or more processors; a memory; one or more application programs stored in the memory and configured to be loaded and executed by the one or more processors to perform the method of testing high band sound absorption coefficients of any of claims 1 to 3.
7. A computer-readable storage medium, on which a computer program is stored which can be loaded and run by a processor to perform the method of testing high band sound absorption coefficient as claimed in any one of claims 1 to 3.
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