The Suppression Of High Frequency Noise Of Tufted Carpet Loom Based On Statistical Energy Analysis

Based on the general project of National Natural Science Foundation of China,"Research on noise source location and identification technology and adaptive active control theory of high-end textile equipment"(fund No.: 51675094),the research on highfrequency noise suppression is carried out.Because of the complex structure and function of tufted carpet loom,there are usually multiple noise sources.The existence of noise will not only shorten the service life of the equipment itself,but also lead to a series of physical and psychological problems and trauma of textile workers.When textile workers are exposed to this kind of extremely strong noise environment for a long time,their hearing organs will be seriously damaged,and even sudden deafness will occur.High frequency noise will also continue to cause textile workers to increase vascular tension,resulting in hypertension and other problems.Statistical Energy Analysis(SEA)method is an effective method to analyze high frequency noise,and the melamine porous soundabsorbing material can effectively suppress high-frequency noise.Hence,combining the two can effectively analyze and suppress high-frequency noise of tufted carpet loom.It is of great significance to analyze and suppress the high frequency noise of tufted carpet loom.In this paper,DHU-2 tufted carpet loom is regarded as the research object.According to the basic principles and assumptions of statistical energy analysis method,the subsystems of tufted carpet loom are divided,and the SEA model of tufted carpet loom is established.The high frequency noise analysis frequency band is determined according to the modal number of the sub-systems.By calculating theoretically the characteristic parameters of tufted carpet loom and measuring experimentally the vibration acceleration of tufted carpet loom,the SEA model noise of tufted carpet loom is obtained.The sound pressure level of DHU-2 tufted carpet loom is measured.The simulation data and experimental data are compared to verify the accuracy of the SEA model.After that,through the determination of noise reduction method and sound absorption material,melamine porous sound-absorbing material is applied to the SEA model of tufted carpet loom to verify the effectiveness of theoretical noise reduction.Furthermore,the melamine porous sound-absorbing material is applied to the research of high-frequency noise suppression of tufted carpet loom,which provides the basis for the full band noise suppression of tufted carpet loom.Firstly,the noise acquisition platform of tufted carpet loom is built,and the actual noise situation of tufted carpet loom is obtained,and the noise characteristics of tufted carpet loom are analyzed.According to the basic components of tufted carpet loom,the SEA geometric model of tufted carpet loom is established by using VA one software.According to the basic assumptions and principles of statistical energy analysis modeling,the tufted carpet loom is divided into nine subsystems,and the structural properties of each subsystem are analyzed.On this basis,the acoustic cavities are divided into 10 cavities in the worker’s working area within 1 m from the tufted carpet loom and the rest in the working area 1 m away from the tufted carpet loom.The SEA model of the tufted carpet loom is established.Based on the principle of statistical energy analysis,this paper analyzes the vibration mode number of each subsystem of tufted carpet loom in different frequency range,divides the specific high frequency analysis frequency band,that is,500 Hz ～ 2000 Hz,and defines the frequency range of the research on high frequency noise of tufted carpet loom in this paper.Secondly,according to the structural properties of each subsystem,three related characteristic parameters are calculated theoretically.According to the basic principle of loom test points,the vibration acceleration of each subsystem in the working state of tufted carpet loom is measured,which is applied to SEA model of tufted carpet loom as excitation to obtain the simulation sound pressure level of tufted carpet loom.At the same time,the sound pressure level of DHU-2 tufted carpet loom is measured,and the sound pressure level data obtained by simulation and experiment are compared.The results show that: the established SEA model of tufted carpet loom has good consistency with the actual work of tufted carpet loom.The maximum error difference is 5.66 d B at 500 Hz.In the high frequency band after 500 Hz,the experimental value is more consistent with the simulation value,that is,the statistical energy analysis method is more accurate for high frequency noise.The accuracy of SEA model of tufted carpet loom is verified,which provides an effective theoretical model for suppressing high frequency noise.Then,the characteristics of different noise reduction materials and the sound absorption principle of porous sound-absorbing materials are analyzed.Based on the statistical energy analysis model of tufted carpet loom,melamine porous sound-absorbing material is used to study the high-frequency noise suppression of tufted carpet loom,and the effectiveness of the noise reduction scheme for high-frequency noise suppression of tufted carpet loom is verified.The results show that the melamine porous sound-absorbing material can effectively suppress the high-frequency noise of tufted carpet loom,and the noise reduction can reach 20 d B in the high frequency band above 800 Hz.Then the highfrequency noise suppression platform of tufted carpet loom is built.The material is applied to the high-frequency noise suppression of tufted carpet loom,and the experimental and theoretical noise reduction situations are compared.Furthermore,the influence of different thickness of melamine porous sound-absorbing material on noise suppression is compared.The results show that in the frequency range of 500 Hz ～ 2000 Hz,the noise reduction effect of melamine porous sound absorption material at 500 Hz in the high frequency range has the biggest difference with the experimental noise reduction effect,the maximum error is 5.5 d B.Moreover,the material thickness is less than 120 mm,its sound absorption performance increases with the increase of thickness,and the sound absorption performance of melamine porous sound absorption material against high frequency noise is weakened when the thickness is more than 120 mm.