Pub Date : 2017-08-31DOI: 10.12677/OJAV.2017.53007
张月, 牛可心, 李惠彬
某轻型载货汽车方向盘在怠速工况下抖动严重，利用模态试验分析其怠速抖动原因，发现方向盘模态频率与发动机二阶点火频率接近，引起共振现象。为降低方向盘振动，结合有限元分析方法和灵敏度分析，调整方向盘结构和仪表台横梁管柱的厚度，对转向系统进行结构优化，从而改变方向盘的固有频率，远离发动机的二阶点火频率，减小共振。最后通过试验验证了改进措施的有效性。 The steering wheel of a light truck has a jitter problem in the idle condition. We used modal test to analyze the jitter reason under idle condition. It is found that the modal frequency of the steering wheel is close to the second order ignition frequency of the engine so the resonance of the steering wheel appears. In order to reduce the steering wheel vibration, we combined with the finite element analysis method and sensitivity analysis method. We adjusted the structure of the steering wheel and the thickness of the instrument panel beam to optimize the structure, thereby changing the natural frequency of the steering wheel. Measures works and the natural frequency was far from the second order ignition frequency of the engine. Finally, the effectiveness and rationality of the improvements were verified through tests.
某轻型载货汽车方向盘在怠速工况下抖动严重，利用模态试验分析其怠速抖动原因，发现方向盘模态频率与发动机二阶点火频率接近，引起共振现象。为降低方向盘振动，结合有限元分析方法和灵敏度分析，调整方向盘结构和仪表台横梁管柱的厚度，对转向系统进行结构优化，从而改变方向盘的固有频率，远离发动机的二阶点火频率，减小共振。最后通过试验验证了改进措施的有效性。 The steering wheel of a light truck has a jitter problem in the idle condition. We used modal test to analyze the jitter reason under idle condition. It is found that the modal frequency of the steering wheel is close to the second order ignition frequency of the engine so the resonance of the steering wheel appears. In order to reduce the steering wheel vibration, we combined with the finite element analysis method and sensitivity analysis method. We adjusted the structure of the steering wheel and the thickness of the instrument panel beam to optimize the structure, thereby changing the natural frequency of the steering wheel. Measures works and the natural frequency was far from the second order ignition frequency of the engine. Finally, the effectiveness and rationality of the improvements were verified through tests.
{"title":"基于灵敏度分析的某轻卡方向盘怠速抖动治理研究 Research on Idle Jitter Control of a Light Truck Steering Wheel Based on Sensitivity Analysis","authors":"张月, 牛可心, 李惠彬","doi":"10.12677/OJAV.2017.53007","DOIUrl":"https://doi.org/10.12677/OJAV.2017.53007","url":null,"abstract":"某轻型载货汽车方向盘在怠速工况下抖动严重，利用模态试验分析其怠速抖动原因，发现方向盘模态频率与发动机二阶点火频率接近，引起共振现象。为降低方向盘振动，结合有限元分析方法和灵敏度分析，调整方向盘结构和仪表台横梁管柱的厚度，对转向系统进行结构优化，从而改变方向盘的固有频率，远离发动机的二阶点火频率，减小共振。最后通过试验验证了改进措施的有效性。 The steering wheel of a light truck has a jitter problem in the idle condition. We used modal test to analyze the jitter reason under idle condition. It is found that the modal frequency of the steering wheel is close to the second order ignition frequency of the engine so the resonance of the steering wheel appears. In order to reduce the steering wheel vibration, we combined with the finite element analysis method and sensitivity analysis method. We adjusted the structure of the steering wheel and the thickness of the instrument panel beam to optimize the structure, thereby changing the natural frequency of the steering wheel. Measures works and the natural frequency was far from the second order ignition frequency of the engine. Finally, the effectiveness and rationality of the improvements were verified through tests.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2017-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47149361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Acoustic measurements or ultrasonic testing can be strongly affected by reflections or echoes from test tank walls. In order to create a non-reflecting environment equivalent to infinite medium, a pyramidal structured absorber (PSA) can be used to coat the walls of an ultrasonic tank. In this work, we model an array of tetragonal pyramid ultrasonic wave absorbers. This model is based on two coupled first-order equations describing the stress and particle velocity within an isotropic medium. For absorbing media, the Kelvin-Voigt model of viscoelasticity is used. The equations are discretized in 2D using an efficient time-stepping pseudo-spectral scheme that takes in consideration both, the acoustic properties and attenuation characteristics of the composite materials. We then built a 3D printed PSA using a Stratasys Objet500 Connex 3D printer, which allows to combine photopolymers in specific concentrations and microstructures. We designed PSA covering the frequency ranges from 0.5 MHz to 5 MHz and from 1 MHz to 10 MHz, with double homogeneous layer: a core of rubber material with a skin of a variety of elastomers by combining rigid and flexible materials. Each single pyramid contains two major parts: the ground of the pyramid (9.4 mm base × 4.7 mm height, for 0.5 MHz and 4.7 mm base × 2.35 mm height, for 1 MHz) and the body of the pyramid (23.5 mm height, for 0.5 MHZ and 11.75 mm height, for 1 MHz). The measured echo-reduction was greater than 35 dB at the covering frequency range and the transmission loss was estimated by 20 dB. Echoes increase rapidly for frequencies below the minimum frequency of the covering range. The modeling and 3D printing of PSA with different sizes, in a wide range of frequencies, is a cost-effective custom solution for a wide range of applications including for example, radiation force balances, hydrophone mounts and medical ultrasound equipment.
{"title":"Rapid Prototyping of Pyramidal Structured Absorbers for Ultrasound","authors":"Fabián Acquaticci, M. M. Yommi, S. Gwirc, S. Lew","doi":"10.4236/OJA.2017.73008","DOIUrl":"https://doi.org/10.4236/OJA.2017.73008","url":null,"abstract":"Acoustic measurements or ultrasonic testing can be strongly affected by reflections or echoes from test tank walls. In order to create a non-reflecting environment equivalent to infinite medium, a pyramidal structured absorber (PSA) can be used to coat the walls of an ultrasonic tank. In this work, we model an array of tetragonal pyramid ultrasonic wave absorbers. This model is based on two coupled first-order equations describing the stress and particle velocity within an isotropic medium. For absorbing media, the Kelvin-Voigt model of viscoelasticity is used. The equations are discretized in 2D using an efficient time-stepping pseudo-spectral scheme that takes in consideration both, the acoustic properties and attenuation characteristics of the composite materials. We then built a 3D printed PSA using a Stratasys Objet500 Connex 3D printer, which allows to combine photopolymers in specific concentrations and microstructures. We designed PSA covering the frequency ranges from 0.5 MHz to 5 MHz and from 1 MHz to 10 MHz, with double homogeneous layer: a core of rubber material with a skin of a variety of elastomers by combining rigid and flexible materials. Each single pyramid contains two major parts: the ground of the pyramid (9.4 mm base × 4.7 mm height, for 0.5 MHz and 4.7 mm base × 2.35 mm height, for 1 MHz) and the body of the pyramid (23.5 mm height, for 0.5 MHZ and 11.75 mm height, for 1 MHz). The measured echo-reduction was greater than 35 dB at the covering frequency range and the transmission loss was estimated by 20 dB. Echoes increase rapidly for frequencies below the minimum frequency of the covering range. The modeling and 3D printing of PSA with different sizes, in a wide range of frequencies, is a cost-effective custom solution for a wide range of applications including for example, radiation force balances, hydrophone mounts and medical ultrasound equipment.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"7 1","pages":"83-93"},"PeriodicalIF":0.0,"publicationDate":"2017-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47901518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Madrigal-Melchor, A. Enciso-Muñoz, D. Contreras-Solorio, X. Saldaña-Saldaña, R. Reyes-Villagrana
Using the transfer matrix method we calculate the frequency dependence of the transmission of longitudinal elastic waves for a layered structure where the specific acoustic impedance of the layers with odd numbering follows a Gaussian distribution, while the inserted even layers have the same impedance as the propagation medium. The structure presents intervals of low-pass, band-stop, and band-pass. The characteristics of the bands depend on the number of layers, on the contrast between the maximum and minimum impedances of the structure, and on the ratio of the width of the inserted layers to the width of the layers with a Gaussian distribution of impedances.
{"title":"A New Alternative Method for the Generation of Acoustic Filters, Modulating Acoustic Impedance: Theoretical Model","authors":"J. Madrigal-Melchor, A. Enciso-Muñoz, D. Contreras-Solorio, X. Saldaña-Saldaña, R. Reyes-Villagrana","doi":"10.4236/OJA.2017.73005","DOIUrl":"https://doi.org/10.4236/OJA.2017.73005","url":null,"abstract":"Using the transfer matrix method we calculate the frequency dependence of the transmission of longitudinal elastic waves for a layered structure where the specific acoustic impedance of the layers with odd numbering follows a Gaussian distribution, while the inserted even layers have the same impedance as the propagation medium. The structure presents intervals of low-pass, band-stop, and band-pass. The characteristics of the bands depend on the number of layers, on the contrast between the maximum and minimum impedances of the structure, and on the ratio of the width of the inserted layers to the width of the layers with a Gaussian distribution of impedances.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"7 1","pages":"39-51"},"PeriodicalIF":0.0,"publicationDate":"2017-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47574802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is well established that musical sounds comprising multiple partials with frequencies approximately in the ratio of small integers give rise to a strong sensation of pitch even if the lowest or fundamental partial is missing—the so-called virtual pitch effect. Experiments on thirty test subjects demonstrate that this virtual pitch is shifted significantly by changes in the spacing of the constituent partials. The experiments measured pitch by comparison of sounds of similar timbre and were automated so that they could be performed remotely across the Internet. Analysis of the test sounds used shows that the pitch shifts are not predicted by Terhardt’s classic model of virtual pitch. The test sounds used were modelled on the sounds of church bells, but a further experiment on seventeen test subjects showed that changes in partial amplitude only had a minor effect on the pitch shifts observed, and that a pitch shift was still observed when two of the lowest frequency partials were removed, so that the effects reported are of general interest.
{"title":"Virtual Pitch and Pitch Shifts in Church Bells","authors":"W. Hibbert, S. Taherzadeh, D. Sharp","doi":"10.4236/OJA.2017.73006","DOIUrl":"https://doi.org/10.4236/OJA.2017.73006","url":null,"abstract":"It is well established that musical sounds comprising multiple partials with frequencies approximately in the ratio of small integers give rise to a strong sensation of pitch even if the lowest or fundamental partial is missing—the so-called virtual pitch effect. Experiments on thirty test subjects demonstrate that this virtual pitch is shifted significantly by changes in the spacing of the constituent partials. The experiments measured pitch by comparison of sounds of similar timbre and were automated so that they could be performed remotely across the Internet. Analysis of the test sounds used shows that the pitch shifts are not predicted by Terhardt’s classic model of virtual pitch. The test sounds used were modelled on the sounds of church bells, but a further experiment on seventeen test subjects showed that changes in partial amplitude only had a minor effect on the pitch shifts observed, and that a pitch shift was still observed when two of the lowest frequency partials were removed, so that the effects reported are of general interest.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"07 1","pages":"52-68"},"PeriodicalIF":0.0,"publicationDate":"2017-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44797294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stimulation of medial olivocochlear (MOC) efferent neurons reduces basilar membrane (BM) sensitivity and increases the slope of BM input-output (I/O) functions in animal models. Decreased compression of I/O functions associated with activation of MOC efferent neurons may assist in extending the neural response to the tone above that of noise, leading to an improvement in masked thresholds. To evaluate this hypothesis, the distortion-product otoacoustic emission (DPOAE) I/O function, a proxy measure of BM compression, was examined in conditions with presentation of contralateral noise. DPOAE I/O functions were measured at f2 frequencies of 1000 and 2000 Hz in 16 normal-hearing adults. In each subject, estimation of masked thresholds at 1000 and 2000 Hz was provided by a two-interval forced-choice procedure. There were statistically significant associations between DPOAE I/O function slopes and masked tone thresholds at both 1000 and 2000 Hz. At 1000 Hz, individuals with higher DPOAE I/O function slopes exhibited lower masked thresholds. Data at 2000 Hz indicated that individuals with higher masked thresholds exhibited higher DPOAE I/O function slopes. When measured with contralateral noise, DPOAE I/O function slopes were linked to masked thresholds at both frequencies examined in this study. Linearized DPOAE I/O functions presumably reflect linearized BM growth functions under conditions of MOC efferent activation, and this process may have extended the neural response to the signal tone so that it could be more easily heard in the presence of masking noise under certain conditions examined in this study.
{"title":"The Role of Efferent Reduction of Cochlear Compression in the Detection of Tones in Noise","authors":"Shaum P. Bhagat, Anusha Yellamsetty","doi":"10.4236/OJA.2017.73007","DOIUrl":"https://doi.org/10.4236/OJA.2017.73007","url":null,"abstract":"Stimulation of medial olivocochlear (MOC) efferent neurons reduces basilar membrane (BM) sensitivity and increases the slope of BM input-output (I/O) functions in animal models. Decreased compression of I/O functions associated with activation of MOC efferent neurons may assist in extending the neural response to the tone above that of noise, leading to an improvement in masked thresholds. To evaluate this hypothesis, the distortion-product otoacoustic emission (DPOAE) I/O function, a proxy measure of BM compression, was examined in conditions with presentation of contralateral noise. DPOAE I/O functions were measured at f2 frequencies of 1000 and 2000 Hz in 16 normal-hearing adults. In each subject, estimation of masked thresholds at 1000 and 2000 Hz was provided by a two-interval forced-choice procedure. There were statistically significant associations between DPOAE I/O function slopes and masked tone thresholds at both 1000 and 2000 Hz. At 1000 Hz, individuals with higher DPOAE I/O function slopes exhibited lower masked thresholds. Data at 2000 Hz indicated that individuals with higher masked thresholds exhibited higher DPOAE I/O function slopes. When measured with contralateral noise, DPOAE I/O function slopes were linked to masked thresholds at both frequencies examined in this study. Linearized DPOAE I/O functions presumably reflect linearized BM growth functions under conditions of MOC efferent activation, and this process may have extended the neural response to the signal tone so that it could be more easily heard in the presence of masking noise under certain conditions examined in this study.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"7 1","pages":"69-82"},"PeriodicalIF":0.0,"publicationDate":"2017-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42482359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sound absorbers including porous materials are used widely for noise control. The most widely-exploited and acknowledged absorption mechanism in porous materials is viscous friction due to relative motion between solid and fluid. Acoustical performance of woven (carpet) and nonwoven (felt) materials made of wool using a traditional technique was investigated. Absorption coefficient of felt was measured using standing wave tube method with and without an air cavity. Data were compared with predictions determined using the laws of Delany and Bazely. Very good agreement between data and predictions was observed. Sound absorption coefficients of both materials also were measured using an impedance gun technique over a wider frequency range. Absorption coefficient obtained using impedance gun method shows that the absorption coefficient of felt is higher than the absorption coefficient of carpet for mid and higher frequencies. Furthermore insertion loss (IL) of the felt was measured in a circular duct. It is found that felt can attenuate sound pressure level between 1 dB and 10 dB.
{"title":"Characterization of Acoustical Properties of Felt and Carpet Made of Natural and Environmentally Friendly Materials","authors":"Haydar Aygün","doi":"10.4236/OJA.2017.72004","DOIUrl":"https://doi.org/10.4236/OJA.2017.72004","url":null,"abstract":"Sound absorbers including porous materials are used widely for noise control. The most widely-exploited and acknowledged absorption mechanism in porous materials is viscous friction due to relative motion between solid and fluid. Acoustical performance of woven (carpet) and nonwoven (felt) materials made of wool using a traditional technique was investigated. Absorption coefficient of felt was measured using standing wave tube method with and without an air cavity. Data were compared with predictions determined using the laws of Delany and Bazely. Very good agreement between data and predictions was observed. Sound absorption coefficients of both materials also were measured using an impedance gun technique over a wider frequency range. Absorption coefficient obtained using impedance gun method shows that the absorption coefficient of felt is higher than the absorption coefficient of carpet for mid and higher frequencies. Furthermore insertion loss (IL) of the felt was measured in a circular duct. It is found that felt can attenuate sound pressure level between 1 dB and 10 dB.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"7 1","pages":"27-38"},"PeriodicalIF":0.0,"publicationDate":"2017-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42684371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-05-03DOI: 10.12677/OJAV.2017.52003
董立国, 王长龙, 王秋芳
根据实际工作中的降噪工程案例，首先分析了有限空间内的噪声频谱特性，再根据噪声频谱特性进行了吸声设计，最后确定了穿孔板厚度，孔径，穿孔率等设计参数，取得了良好的降噪效果。 According to the case of noise reduction in practical work, the noise spectrum characteristics in finite space are analyzed, and then the sound absorption design is carried out according to the noise spectrum characteristics. Finally, the design parameters such as thickness, aperture and perforation of perforated plate are determined, achieving good noise reduction effect.
根据实际工作中的降噪工程案例，首先分析了有限空间内的噪声频谱特性，再根据噪声频谱特性进行了吸声设计，最后确定了穿孔板厚度，孔径，穿孔率等设计参数，取得了良好的降噪效果。 According to the case of noise reduction in practical work, the noise spectrum characteristics in finite space are analyzed, and then the sound absorption design is carried out according to the noise spectrum characteristics. Finally, the design parameters such as thickness, aperture and perforation of perforated plate are determined, achieving good noise reduction effect.
{"title":"中央空调机房的噪声分析与共振吸声体设计 Noise Analysis and Resonant Absorber Design of Central Air Conditioning Room","authors":"董立国, 王长龙, 王秋芳","doi":"10.12677/OJAV.2017.52003","DOIUrl":"https://doi.org/10.12677/OJAV.2017.52003","url":null,"abstract":"根据实际工作中的降噪工程案例，首先分析了有限空间内的噪声频谱特性，再根据噪声频谱特性进行了吸声设计，最后确定了穿孔板厚度，孔径，穿孔率等设计参数，取得了良好的降噪效果。 According to the case of noise reduction in practical work, the noise spectrum characteristics in finite space are analyzed, and then the sound absorption design is carried out according to the noise spectrum characteristics. Finally, the design parameters such as thickness, aperture and perforation of perforated plate are determined, achieving good noise reduction effect.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"05 1","pages":"13-18"},"PeriodicalIF":0.0,"publicationDate":"2017-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45340931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-05-03DOI: 10.12677/OJAV.2017.52005
陈秀慧, 赵宇轩, 秦锴, 王靖
基于MATLAB设计了一个支持单、双声道的语音信号处理系统，可实现语音信号的分析、加噪及窗函数滤波。针对语音信号中所添加的不同频段的噪声，可自主地选择合适的窗函数完成噪声滤波，并进行各种滤波效果的对比。实验表明：该系统界面友好、操作简单，便于直观了解语音信号和滤波器特性，可用于作教学演示等。 A GUI for signal procession system for single-way or two-way sounds is presented, based on MATLAB, where various operations can be carried out such as analysing sound signals, adding noise, filtering by window function method. On account of the noise at different frequencies added to the original sound signal, applicable window function can be utilized to complete filtration independently. This experiment manifests that it is convenient to understand sound signals and filter’s characteristics on this GUI, because of its simplified procedures and friendly interface, which makes this GUI perfect for teaching use.
基于MATLAB设计了一个支持单、双声道的语音信号处理系统，可实现语音信号的分析、加噪及窗函数滤波。针对语音信号中所添加的不同频段的噪声，可自主地选择合适的窗函数完成噪声滤波，并进行各种滤波效果的对比。实验表明：该系统界面友好、操作简单，便于直观了解语音信号和滤波器特性，可用于作教学演示等。 A GUI for signal procession system for single-way or two-way sounds is presented, based on MATLAB, where various operations can be carried out such as analysing sound signals, adding noise, filtering by window function method. On account of the noise at different frequencies added to the original sound signal, applicable window function can be utilized to complete filtration independently. This experiment manifests that it is convenient to understand sound signals and filter’s characteristics on this GUI, because of its simplified procedures and friendly interface, which makes this GUI perfect for teaching use.
{"title":"基于MATLAB的双声道语音信号分析及处理系统 Two-Way Sound Signals Analysis and Procession System Based on MATLAB-GUI","authors":"陈秀慧, 赵宇轩, 秦锴, 王靖","doi":"10.12677/OJAV.2017.52005","DOIUrl":"https://doi.org/10.12677/OJAV.2017.52005","url":null,"abstract":"基于MATLAB设计了一个支持单、双声道的语音信号处理系统，可实现语音信号的分析、加噪及窗函数滤波。针对语音信号中所添加的不同频段的噪声，可自主地选择合适的窗函数完成噪声滤波，并进行各种滤波效果的对比。实验表明：该系统界面友好、操作简单，便于直观了解语音信号和滤波器特性，可用于作教学演示等。 A GUI for signal procession system for single-way or two-way sounds is presented, based on MATLAB, where various operations can be carried out such as analysing sound signals, adding noise, filtering by window function method. On account of the noise at different frequencies added to the original sound signal, applicable window function can be utilized to complete filtration independently. This experiment manifests that it is convenient to understand sound signals and filter’s characteristics on this GUI, because of its simplified procedures and friendly interface, which makes this GUI perfect for teaching use.","PeriodicalId":63563,"journal":{"name":"声学期刊(英文)","volume":"05 1","pages":"27-33"},"PeriodicalIF":0.0,"publicationDate":"2017-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46837625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-05-03DOI: 10.12677/OJAV.2017.52004
董新峰, 黄铁铮, 朱全军, 曹枚根, 王昊, 任建兴
针对高压电流互感器抗震能力较为薄弱的问题，以某型电流互感器为研究对象，开展其抗震及减震性能分析研究，旨在确保高压电流互感器在地震发生时的无破坏性。文中基于ANSYS开展电流互感器模态分析研究，获得电流互感器的固有频率和模态振型，确定电流互感器易损坏的部位；根据美国变电站抗震设计推荐规程IEEE Std-693-2005和高压开关设备抗地震性能试验GB/T13540-2009要求，选用天然Elcentro波和Taft波对高压电流互感器进行水平激励，开展易损坏部位的位移和应力时程分析，确定其最大位移和最大应力，为电流互感器的抗震设计优化提供技术支撑。 According to the weak character of seismic capacity of high voltage current transformer and en-suring no damage at the time of the earthquake, the current transformer is used as research object to carry out the aseismic capacity and seismic isolation analysis. Firstly, the modal analysis of high voltage current transformer is carried out, and the natural frequency and mode shape of the breaker are calculated, and the easily damaged parts of high voltage current transformer are determined. Secondly, according to the standards of the IEEE Std-693-2005 and GB/T13540-92, natural El-centro wave and Taft wave are used to carry out the level excitation of the high voltage current transformer, and the time history analysis of the displacement and stress of the vulnerable parts of current transformer is carried out, and the maximum displacement and maximum stress of vulnerable parts are determined. The above research can provide technical support for the seismic design optimization of the current transformer.
针对高压电流互感器抗震能力较为薄弱的问题，以某型电流互感器为研究对象，开展其抗震及减震性能分析研究，旨在确保高压电流互感器在地震发生时的无破坏性。文中基于ANSYS开展电流互感器模态分析研究，获得电流互感器的固有频率和模态振型，确定电流互感器易损坏的部位；根据美国变电站抗震设计推荐规程IEEE Std-693-2005和高压开关设备抗地震性能试验GB/T13540-2009要求，选用天然Elcentro波和Taft波对高压电流互感器进行水平激励，开展易损坏部位的位移和应力时程分析，确定其最大位移和最大应力，为电流互感器的抗震设计优化提供技术支撑。 According to the weak character of seismic capacity of high voltage current transformer and en-suring no damage at the time of the earthquake, the current transformer is used as research object to carry out the aseismic capacity and seismic isolation analysis. Firstly, the modal analysis of high voltage current transformer is carried out, and the natural frequency and mode shape of the breaker are calculated, and the easily damaged parts of high voltage current transformer are determined. Secondly, according to the standards of the IEEE Std-693-2005 and GB/T13540-92, natural El-centro wave and Taft wave are used to carry out the level excitation of the high voltage current transformer, and the time history analysis of the displacement and stress of the vulnerable parts of current transformer is carried out, and the maximum displacement and maximum stress of vulnerable parts are determined. The above research can provide technical support for the seismic design optimization of the current transformer.
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Pub Date : 2017-05-03DOI: 10.12677/OJAV.2017.52006
徐一鸣
在发动机运行过程中，燃烧室内部时刻发生着剧烈的燃烧，不可避免地存在热-声-振耦合作用，长期的高温高压高声强工作环境会对燃烧室结构疲劳寿命和发动机正常工作产生至关重要的影响。本文利用ANSYS-WORKBENCH软件以单向耦合的方式对燃烧室结构的热-声-振特性进行了模拟分析，即先在FLUENT模块中进行燃烧运算得到流体域温度场、压力场等，然后利用稳态热分析模块获得结构上的温度场分布，最后把得到的温度场和压力场作为预应力施加给结构，对内部填充气体的燃烧室做了有预应力的单向热-声-振耦合模态分析，也对不考虑声-振耦合的燃烧室结构做了热-振耦合模态分析，得到了8阶模态频率和模态振型。结果表明，低阶模态主要包含了弯曲模态和扭转模态，而空腔模态在较高频率才出现。此外，考虑声-振耦合作用得到的各阶模态频率比不考虑声-振耦合得到的模态频率要小。 During the aero-engine operation, the intense combustion happens inside the combustion cham-ber and the thermo-acoustics-vibration interaction exists unavoidably. The operating environ-mental under high temperature, high pressure and high acoustical level has a great influence on the fatigue life of the structure and the normal operation of the aero-engine. Simulation analysis of the thermo-acoustics-vibration of combustion chamber was done through one-way coupling by ANSYS-WORKBENCH software. At first the combustion computing was done in FLUENT module in order to obtain the data of temperature and pressure fields. Then the temperature distribution on the structure through steady thermal analysis module was obtained to feed into the pre-stress structure. Modal parameters including eight modal frequencies and eight mode shapes were identified both by one-way thermo-acoustics-vibration coupling and thermo-vibration coupling. The results show that bending and torsional modes appear at lower frequencies earlier, and the cavity modes appear at higher frequencies. In addition, modal frequencies from one-way thermo-acoustics-vibration coupling are lower than those from uncoupling.
在发动机运行过程中，燃烧室内部时刻发生着剧烈的燃烧，不可避免地存在热-声-振耦合作用，长期的高温高压高声强工作环境会对燃烧室结构疲劳寿命和发动机正常工作产生至关重要的影响。本文利用ANSYS-WORKBENCH软件以单向耦合的方式对燃烧室结构的热-声-振特性进行了模拟分析，即先在FLUENT模块中进行燃烧运算得到流体域温度场、压力场等，然后利用稳态热分析模块获得结构上的温度场分布，最后把得到的温度场和压力场作为预应力施加给结构，对内部填充气体的燃烧室做了有预应力的单向热-声-振耦合模态分析，也对不考虑声-振耦合的燃烧室结构做了热-振耦合模态分析，得到了8阶模态频率和模态振型。结果表明，低阶模态主要包含了弯曲模态和扭转模态，而空腔模态在较高频率才出现。此外，考虑声-振耦合作用得到的各阶模态频率比不考虑声-振耦合得到的模态频率要小。 During the aero-engine operation, the intense combustion happens inside the combustion cham-ber and the thermo-acoustics-vibration interaction exists unavoidably. The operating environ-mental under high temperature, high pressure and high acoustical level has a great influence on the fatigue life of the structure and the normal operation of the aero-engine. Simulation analysis of the thermo-acoustics-vibration of combustion chamber was done through one-way coupling by ANSYS-WORKBENCH software. At first the combustion computing was done in FLUENT module in order to obtain the data of temperature and pressure fields. Then the temperature distribution on the structure through steady thermal analysis module was obtained to feed into the pre-stress structure. Modal parameters including eight modal frequencies and eight mode shapes were identified both by one-way thermo-acoustics-vibration coupling and thermo-vibration coupling. The results show that bending and torsional modes appear at lower frequencies earlier, and the cavity modes appear at higher frequencies. In addition, modal frequencies from one-way thermo-acoustics-vibration coupling are lower than those from uncoupling.
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