Since the 1970s, Fang Danqun has organized a large collaborative group with the Beijing Labor Protection Science Institute, Beijing Ear Research Institute, Beijing Medical College, Institute of Psychology, Chinese Academy of Sciences, and Beijing Health and Epidemic Prevention Station to conduct in-depth research on noise The results of this study on the impact on hearing, cardiovascular, and nervous systems led to the formulation of the first comprehensive national noise standard for China - the Noise Hygiene Standard for Industrial Enterprises, which was promulgated by the Ministry of Health and the State Labor Administration in 1980 for trial implementation. Then, commissioned by the State Construction Commission, the author of this article, Fang Danqun, formed a larger team, including almost all noise-related research in the country, and design units participated in this work. For example, editor-in-chief: Beijing Institute of Labor Protection Science. Participating units: China Academy of Architectural Sciences, Institute of Acoustics, Chinese Academy of Sciences, Shanghai Industrial Architecture Design Institute, Shanghai Civil Architecture Design Institute, Shanghai Chemical Industry Design Institute, Chongqing Iron and Steel Design Institute of the Ministry of Metallurgical Industry, Beijing Iron and Steel Design and Research Institute of the Ministry of Metallurgical Industry , the Design and Research Institute of the Ministry of Machinery Industry, the 11th Design Institute of the Ministry of Electronic Industry, the Fourth Planning and Design Institute of the Ministry of Aviation Industry, the Fourth Design Institute of the Ministry of Chemical Industry, and the Chinese Academy of Environmental Sciences. Experts in the noise field, such as Wu Dasheng, Zhang Kuisheng, Feng Yuzheng, Sun Jiaqi, Chen Qian, Zhang Jingkai, Chen Daochang, Xu Zhijiang, Yu Renxing, etc. all participated in this work.
After five years of efforts, 11,794 noise sources in 1,034 factories across the country were tested and analyzed, and the noise exposure status of 62,726 workers was investigated and studied; the physiological effects of noise were deeply explored, especially Carry out computer analysis of the impact of noise on the heart and brain, and obtain a linear relationship between noise level and brain electrical function index. The relationship between the positive rate of deafness caused by occupational noise exposure and the noise level, the relationship between the neurasthenia syndrome caused by occupational noise exposure and the noise level, the linear relationship between the degree of noise annoyance and the noise level, and the relationship between noise and telephone conversation interference. On the basis of the above, the noise standards for various locations in the factory area of ??industrial enterprises (including production workshops, control rooms, offices, medical offices, schools) and factory boundary noise limits are given. Based on the summary of domestic and foreign noise control technology and engineering practice experience dating back to the 1980s, specifications for the overall design, sound insulation design, sound attenuation design, sound absorption design, and vibration isolation design of industrial enterprises are given. . In order to provide a basis for formulating noise standards, the specification preparation team, with the support of relevant departments of the State Council, conducted nearly 100 noise projects in 40 enterprise organizations in 13 provinces and cities across the country in the first half of the 1980s.
Control work pilot. The control engineering practice involves aerodynamic noise sources such as fans, compressors, internal combustion engines, and boiler exhausts. It also deals with air hammers, gear chopping machines, winding machines, jade cutting and grinding machines, manual grinders, and bearing steel balls. Mechanical noise sources such as file ball machines and photodome machines. 95% of the projects met the 90dBA requirement, of which 90% met the 85dBA requirement. This large-scale engineering practice not only provides an example and economic calculation for the implementation of this code for noise control design, but also factually verifies that the vast majority of industrial enterprises can achieve the noise limit values ??set by this code through hard work. requested.
This standard specification, which has been researched and compiled with almost all the efforts of the national noise community and related industries, was approved and promulgated by the State Planning Commission of the People's Republic of China in December 1985. Named: National Standard of the People's Republic of China, GBJ 87-1985 "Design Code for Noise Control in Industrial Enterprises". The approval and promulgation of this design specification marked the birth of noise control engineering. Because from now on, noise is no longer a noise science or noise control within the scope of physical acousticians, but has become the most common subject field in the engineering and industrial circles. This subject not only has theory, but also engineering design and product design. It has truly become An integral part of the engineering discipline. It can be said that noise control engineering is an emerging science and technology field that intersects many disciplines such as physics, acoustics, mechanical engineering, construction engineering, materials science and chemical engineering, computers, mathematics, physiology, and psychology. In the 1980s, another important comprehensive noise standard, the Urban Area Environmental Noise Standard, was compiled by the Institute of Acoustics of the Chinese Academy of Sciences, with participation from the Beijing Labor Insurance Institute, Tongji University, and Beijing Environmental Monitoring Station, and was promulgated by the State Council Environmental Protection Leading Group .
It is particularly pointed out that Professor Ma Dayou, as a consultant, has provided strong guidance on the above important comprehensive noise standards.
During this period, a number of noise limit standards for transportation and general machinery were also promulgated. For example, motor vehicle noise allowable standards, marine ship noise level regulations, inland river ship noise level regulations, air noise limits radiated by marine diesel engines, ambient noise standards for aircraft noise around airports, general small gasoline engine noise limits, and rotating electrical machine noise limits , Earthmoving machinery driver's seat vibration test methods and limits, etc. During this period, environmental vibration standards for urban areas were also promulgated.
This series of large-scale activities in the field of noise since the 1980s, along with the birth of noise control engineering, has brought China's noise control work from a single machine to a new era of comprehensive management of the entire factory and regional environment. In the first stage, a small number of scientific research and design units spontaneously researched and entered a new stage in which government management has rules and laws to follow. Noise control has developed from scientific research in a few acoustic units to widely used in engineering practice and product design in the engineering and technical circles. It has also made China's noise team develop from a few units and a dozen people in the early 1960s to two or three people. Ten units, thousands of scientific and technological personnel, including a group of accomplished and accomplished senior researchers and senior engineering technicians. These years of in-depth research have also enabled China to enter the international advanced ranks in the fields of sound-absorbing structures, airflow noise and mufflers, physiological effects of noise, noise standards, and noise control engineering. What's even more exciting is that China's noise control equipment manufacturing industry started from scratch. By the end of the 1980s, it had formed an industry with hundreds of factories and tens of thousands of employees, producing various types of mufflers, sound absorbers, and insulation. Noise control equipment and instrument manufacturing industry for acoustic components, shock absorbers and acoustic measuring instruments.
With the birth of noise control engineering, the academic activities in the noise control engineering community are extremely active. The first national academic conference on noise control engineering was held in Huangshan in 1982, with 170 papers. In 1984, the 2nd National Noise Control Engineering Academic Conference (Hangzhou Conference), 180 papers were presented. In 1986, the 3rd National Noise Control Engineering Academic Conference (Xi'an Conference), 200 papers were presented. In 1988, the 4th National Noise Control Engineering Academic Conference was held. Control Engineering Academic Conference (Chengdu Conference), 200 papers. In 1987, the 16th International Noise Control Engineering Academic Conference was held in Beijing. Experts from all over the world gathered in Beijing to exchange research progress on noise control engineering. China's achievements in noise control engineering have attracted the attention and attention of colleagues around the world.
In the 1980s, a number of books on noise control were also published, such as L.L. Beranek, Noise And Vibration Control, 1971; L.L. Faulkner, Hanabook of Industrial Noise Control, 1976; C.M. Harris, Handbook of Noise Control, 1979; China also has its own books, such as, edited by Ma Dayou, Noise Control, 1987; Fang Danqun, Aerodynamic Noise and Muffler, 1978; Fang Danqun, Wang Wenqi, Sun Jiaqi, Noise Control, 1986; Noise Reduction by Zhao Songling, etc. and isolation, 1985; Zheng Changju, Hong Zonghui et al., Environmental Noise Control Engineering, 1988; Lu Yuheng et al., Noise and Vibration Control Equipment Selection Manual. 1988; Ren Wentang, Industrial Noise and Vibration Control Technology, 1989; Sun Jiaqi et al., Vibration Hazards and Control Technology , 1989. et al. The professional publication "Noise and Vibration Control" edited by Yan Jikuan was also officially published. Whether in Europe, the United States or China, the 1980s was a prosperous era for noise control, which ushered in the birth and development of noise control engineering. From the 1990s to the present, noise control engineering has developed vigorously around the world.
Noise control engineering leaves "noise control" to the industry. In the past two decades, sound source noise reduction has achieved outstanding results around the world. Taking aircraft noise as an example, it has been reduced from 120 WECPNdB in the 1960s to 80 WECPN dB now. This is a result of investing a lot of manpower, material resources, and financial resources, and using a number of technologies, such as enhanced sound attenuation, sound insulation, and active noise The comprehensive results of controlling and optimizing the body design. It is quite difficult for me.
However, as countries have become more and more strict on aircraft noise restrictions, commercial competition has become more and more fierce. In recent years, the United States and Europe have launched new silent aircraft plans.
For example, Lockheed Martin in the United States is developing a "Quiet Supersonic Transport" that can fly at a maximum speed of 1.6 times the speed of sound. It will use a series of newly developed aerodynamic technologies, especially special The nose and tail rudder are designed in an inverted "V" shape. The aircraft's noise level will be 20 decibels lower than that of the Concorde. Residents on the ground will not be disturbed during flight. The new aircraft is expected to enter service by 2012.
Another set of research and development work is carried out by the Cambridge-MIT Joint Institute (CMI). This is a new design of a high-efficiency wing-body fused passenger aircraft. The wing-body fused silent aircraft named SAX40 aims to have a weighted average noise level of 63 decibels (dBA) around the airport, which is lower than the road traffic noise level. The aircraft’s output is almost inaudible in the surrounding areas of ordinary airports. noise. SAX40 has taken a variety of measures to reduce noise. Its key technologies include: a curved central lifting body capable of low-speed approach and high-efficiency cruise; an embedded, distributed propulsion system, including ultra-high bypass ratio engines and adjustable thrust vector tails Nozzles; there are no conventional flaps on the wings, and their downwardly curved leading edges can be deployed smoothly. The elevons have trailing edge brushes to reduce noise during approach; the rectified landing gear can eliminate noise sources, etc. "Silent" is the first key point in SAI's large civil aircraft research plan, which shows that noise issues have been a key issue for new large civil aircraft in the past 20 years.
The first mission of the U.S. "Seawolf" class attack nuclear submarine is anti-submarine, and reducing noise is crucial to it. Its noise control methods mainly include: the first use of a new "pump jet thruster" to solve the problem of propeller noise; the nuclear power plant uses a natural circulation reactor to reduce loop noise; and the use of steam turbine electric propulsion to replace high-noise deceleration Gearbox; "Active Noise Control Technology" is used for the first time. Each unit adopts effective noise and vibration control technology, and "Active Noise Control Technology" is used for the first time. The comprehensive results make the "Sea Wolf" have low noise It eliminates the background noise of the ocean and becomes a truly "quiet" submarine.
Looking at car noise, it is the most important part of traffic noise. European and American countries have increasingly strict regulations on automobile noise standards. At the same time, factors such as noise, vibration, and comfort have become important indicators of automotive product quality. In order to meet the higher requirements of customers, it is also a thorny issue for automobile manufacturing plants. Because car noise has been reduced many times. Since the 1970s, many methods have been used to reduce automobile noise, such as automobile exhaust mufflers, improvements in automobile mechanical structures, and optimal vibration isolation designs for engines and entire car bodies. On this basis, if we now ask for a reduction of a few decibels, it will be much more difficult than the original reduction of 10 decibels. After the car noise drops to 75 decibels, there is no main noise source and all parts are similar. Through testing and analysis, carefully determine the noise of each part, such as exhaust noise, tire noise, engine noise, gear noise, exhaust noise, transmission noise, etc., how much noise contribution each part makes and how much should be reduced, so that the entire car The noise can be reduced by several decibels. This is a very detailed and difficult task, and it is also the main goal that the European and American automotive industries are going all out to tackle. In recent years, road noise has also attracted people's attention. It is estimated that noise costs the European Union between 10 billion and 40 billion US dollars every year, about half of which comes from road noise. One solution to road/tire noise is to build single-layer porous roads on an asphalt concrete subgrade, which have been paved for hundreds of miles in Europe. In addition to reducing noise, the porous surface also helps with drainage, potentially reducing traffic accidents.
For general machinery and home appliances, ISO also provides "Low-noise Machine Design Guidelines". In the past two decades, low-noise machines have become fashionable commodities in various countries around the world, and manufacturers are rushing to develop low-noise equipment. , as a bargaining chip in market competition. In recent years, China has also made great achievements in the development of low-noise mechanical equipment, such as the low-noise cooling towers developed by Shanghai Jiao Tong University, Tsinghua University, the Fourth Institute of the Ministry of Machinery, Beijing Labor Insurance Institute, Zhejiang Lianfeng Group and other units. Low-noise axial flow fans developed by Shanghai Jiao Tong University, CSSC 711 Institute, Shangyu Wind Turbine Factory, etc., and low-noise woodworking machinery developed by CSSC Ninth Institute, etc., have achieved good noise reduction effects.
Sound source noise reduction has greatly enriched the knowledge base of noise control engineering.
Active noise control, that is, the research and application of electronic mufflers, has also made important progress. The outstanding work of P.A. Nelson and others at the University of Southampton, UK, has turned years of vision into reality in aircraft cockpits, bringing active noise control into the practical stage. . Since then, active noise control has achieved significant noise reduction effects in ships, carriages, central air-conditioning ducts, etc. In this field, the Institute of Acoustics of the Chinese Academy of Sciences, Nanjing University, Northwestern Polytechnical University, etc. have published a series of papers and works.
In terms of noise control engineering theory, significant progress has been made in the theory of vibration, sound radiation, sound field distribution and their coupling, especially with the rapid progress of computer and information technology, Statistical Energy Analysis (SEA) ), the finite element method has successfully entered the theoretical field of noise control engineering, simplifying many rather complex acoustic calculations, such as missile and aircraft noise. Computers use fast Fourier integrals to calculate autocorrelation functions, cross-correlation functions, and coherence functions, which brings people's identification of noise sources and sound intensity measurement to a new level. Important results have also been achieved in the prediction and pre-evaluation of urban traffic noise.
Since the 1990s, due to its wide application in architectural acoustics and other fields, such as the successful application of transparent micro-perforated panels developed by Zha Xueqin and others, micro-perforated panel sound-absorbing materials and technology have once again gained domestic popularity. Foreign colleagues attach great importance to it. Zhao Songling, Liu Ke and others have done a lot of research on the nonlinearity of micro-perforated plates; Tian Jing, Li Xiaodong, Mao Dongxing, Zhang Bin and others have all done in-depth research on the application of micro-perforated plates. In terms of the manufacturing process of microplates, many researchers have proposed various microhole processing methods such as laser drilling, electrical etching, chemical etching, and high-speed jet flow based on the development of materials and production processes. New products such as transparent microplates and variable-aperture microplates have been produced. Other new sound-absorbing materials have also emerged, such as foam glass, foam plastics, metal sintered plates, foam metal, etc.
In recent years, Zhejiang University has conducted research on the subjective annoyance of discontinuous sound sources and low-frequency environmental noise, and many units such as the China Environmental Monitoring Center and the Environmental Engineering Assessment Center of the Ministry of Environmental Protection have conducted research on traffic noise monitoring and prediction. The work of the Ministry of Railways system on railway and train noise has played a role in promoting the development of noise control engineering.
The development of noise control engineering has greatly promoted the industrialization of noise control. Nowadays, a noise control industry has been formed around the world. In Europe and the United States, you can buy the high-quality sound absorbers, mufflers, and sound insulation components you need from many manufacturers and suppliers of noise control equipment and acoustic measurement instruments. , shock absorbers and acoustic measuring instruments. There are also many consulting companies that can design and solve noise problems for you. In China, the general noise control equipment industry has made great progress. A number of serialized and standardized general noise control equipment and acoustic measurement instrument production bases have been formed. Enterprises specializing in the production and manufacturing of noise and vibration control products and engineering technical services There are more than 500 companies. There are tens of thousands of employees. In particular, mufflers that are matched with automobiles and some mechanical equipment have achieved large-scale production. For example, some automobile muffler companies have an annual production capacity of more than 100,000 sets, and an annual output value of hundreds of millions of yuan. At present, the annual output value of automobile mufflers nationwide has reached more than one billion yuan. In recent years, the scale of noise control projects has become larger and larger. In Europe and the United States, overall noise control at airports and sound insulation barriers on highways cost millions, tens of millions, or even hundreds of millions of dollars. Dollar. In China, there are many noise control projects worth tens of millions, such as Beijing Green Acoustics Co., Ltd., 1) Noise control project of Beijing Taiyanggong Gas Thermal Power Plant worth 45 million yuan; 2) Noise control project of Zhengchangzhuang Thermal Power Plant worth 53 million yuan; 3) Capital City The airport terminal noise control project costs 20 million yuan. Shenzhen Mechanical and Electrical Industrial Co., Ltd., 1) GE Xiamen aerospace engine test bed silencer, 31 million; 2) Shenzhen Metro Phase 1, Line 3, Guangzhou Metro Line 3, Line 5, Chongqing Metro, Xi'an Metro Line 2, Each of these six projects costs more than 17 million yuan; a series of highway sound insulation barriers such as Shanghai Shenhua Acoustic Equipment Co., Ltd. and Shanghai Xinhuajing Environmental Protection Company are also large-scale noise control projects worth more than 10 million yuan. In these projects, noise control engineering fully plays its role.
In China, there are currently more than 50 units engaged in scientific research, design, teaching, and monitoring of noise and vibration control, with thousands of technical personnel. Form a relatively strong technical team.
As the backbone of noise control engineering, this team has established a relatively complete system of noise control regulations and standards in China. For example, the Law of the People's Republic of China on the Prevention and Control of Environmental Noise Pollution, Environmental Noise Quality Standards, Loud Emission Standards, Emission Standards for Various Noise Sources, Technical Standards for Various Noise Control Equipment, Noise Testing and Prediction Evaluation Standards, Noise Control Technology More than 100 standards and specifications. He has published a considerable number of papers, systematically summarizing and introducing the latest achievements and developments in noise and vibration noise technology at home and abroad, playing an important role in promoting the development of noise control engineering. In 2008, the Ministry of Environmental Protection approved the Beijing Labor Insurance Institute to build the "National Environmental Protection Noise Control Engineering and Technology Center". This is also a major event in the noise control engineering community and will surely play an important role in the noise control cause.
Following the International Noise Control Engineering Conference held in my country in 1987, in October 2008, the 37th International Noise Control Engineering Conference was held in Shanghai. The conference content mainly covers environmental noise, architectural acoustics, noise and vibration control, noise policy and management, numerical models and simulation calculations, signal processing and measurement instruments, sound landscape, sound quality, active noise and vibration control, and the impact of vibration and impact. , structural acoustics, aeroacoustics, occupational noise and its protection, noise maps, aircraft and vehicle noise, beam forming and acoustic holography and other fields. Tian Jing, the chairman of this conference, gave a conference report on the research progress of micro-perforated plates at the conference. At the same time, a large number of the latest domestic research results were reported at the conference, allowing scholars from all over the world to further understand China's research characteristics in this field. The convening of two international noise control engineering conferences in my country is the international noise community's recognition of the development and progress of my country's noise control technology. It also marks a new milestone in my country's noise control work and promotes the development and progress of noise control engineering in my country. Complete.
The 2009 National Noise Control Engineering Academic Conference in China has now entered its eleventh session. It is jointly organized by nine societies and associations related to noise control engineering, which shows that there are successors to my country's noise control engineering. Prosperity and prosperity.