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碳中和 4

节能减排 4

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噪声 2

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C-Bézier曲面;降阶;边界约束 1

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Design of noise-reduction seats for high-speed trains

Xiaojun DENG, Yanju ZHAO, Haijin ZHANG, Renzhong SHUAI, Leiwei ZHU

《机械工程前沿(英文)》 2018年 第13卷 第3期   页码 385-389 doi: 10.1007/s11465-017-0438-x

摘要:

Noise-reduction seats have been successfully used in concert halls, theaters, and other places that reduce noise. In this study, a new noise-reduction seat design was proposed for high-speed trains, which have unique interior noise spectral characteristics. First, before the noise-reduction seat models were fabricated, the parameters of high-performance sound-absorbing materials and perforated plates were selected by conducting a standing-wave tube test. The sound-absorption effects of the noise-reduction seats and normal seats were investigated and compared in a reverberation chamber. Test results showed that, compared with normal seats, the noise-reduction seats obtained a significantly improved sound-absorption coefficient in the entire frequency band. Furthermore, the test results were used to establish a simulation model for calculation, and the simulation results proved that the noise-reduction seats substantially reduced the noise in an entire train car. Finally, the noise-reduction seats were fabricated and installed in a full train car of an actual high-speed train. The test results showed that, compared with the normal seats, the noise-reduction seats decreased the noise level at a standard point in the passenger car by 1.5 dB. Therefore, the noise-reduction seats are effective in noise reduction.

关键词: high-speed train     sound-absorbing materials     perforated board     noise-reduction seats    

Application of python-based Abaqus preprocess and postprocess technique in analysis of gearbox vibration and noisereduction

Guilian YI, Yunkang SUI, Jiazheng DU

《机械工程前沿(英文)》 2011年 第6卷 第2期   页码 229-234 doi: 10.1007/s11465-011-0128-z

摘要:

To reduce vibration and noise, a damping layer and constraint layer are usually pasted on the inner surface of a gearbox thin shell, and their thicknesses are the main parameters in the vibration and noise reduction design. The normal acceleration of the point on the gearbox surface is the main index that can reflect the vibration and noise of that point, and the normal accelerations of different points can reflect the degree of the vibration and noise of the whole structure. The K-S function is adopted to process many points’ normal accelerations as the comprehensive index of the vibration characteristics of the whole structure, and the vibration acceleration level is adopted to measure the degree of the vibration and noise. Secondary development of the Abaqus preprocess and postprocess on the basis of the Python scripting programming automatically modifies the model parameters, submits the job, and restarts the analysis totally, which avoids the tedious work of returning to the Abaqus/CAE for modifying and resubmitting and improves the speed of the preprocess and postprocess and the computational efficiency.

关键词: Abaqus secondary development     Python language     vibration and noise reduction     K-S function     vibration acceleration level    

Noise reduction for centrifugal fan with non-isometric forward-swept blade impeller

MA Jianfeng, QI Datong, MAO Yijun

《能源前沿(英文)》 2008年 第2卷 第4期   页码 433-437 doi: 10.1007/s11708-008-0082-6

摘要: To reduce the noise of the T9-19No.4A centrifugal fan, whose impeller has equidistant forward-swept blades, two new impellers with different blade spacing were designed and an experimental study was conducted. Both the fan’s aerodynamic performance and noise were measured when the two redesigned impellers were compared with the original ones. The test results are discussed in detail and the effect of the noise reduction method for a centrifugal fan using impellers with non-isometric forward-swept blades was analyzed, which can serve as a reference for researches on reduction of fan noise.

关键词: different     reference     aerodynamic performance     centrifugal     impeller    

A fully solid-state cold thermal energy storage device for car seats using shape-memory alloys

《能源前沿(英文)》 2023年 第17卷 第4期   页码 504-515 doi: 10.1007/s11708-022-0855-3

摘要: Thermal energy storage has been a pivotal technology to fill the gap between energy demands and energy supplies. As a solid-solid phase change material, shape-memory alloys (SMAs) have the inherent advantages of leakage free, no encapsulation, negligible volume variation, as well as superior energy storage properties such as high thermal conductivity (compared with ice and paraffin) and volumetric energy density, making them excellent thermal energy storage materials. Considering these characteristics, the design of the shape-memory alloy based the cold thermal energy storage system for precooling car seat application is introduced in this paper based on the proposed shape-memory alloy-based cold thermal energy storage cycle. The simulation results show that the minimum temperature of the metal boss under the seat reaches 26.2 °C at 9.85 s, which is reduced by 9.8 °C, and the energy storage efficiency of the device is 66%. The influence of initial temperature, elastocaloric materials, and the shape-memory alloy geometry scheme on the performance of car seat cold thermal energy storage devices is also discussed. Since SMAs are both solid-state refrigerants and thermal energy storage materials, hopefully the proposed concept can promote the development of more promising shape-memory alloy-based cold and hot thermal energy storage devices.

关键词: shape-memory alloy (SMA)     elastocaloric effect (eCE)     cooled seat     cold thermal energy storage    

基于经验模式分解的旋转机械振动信号降噪处理

杨建文,贾民平,许飞云,胡建中

《中国工程科学》 2005年 第7卷 第8期   页码 66-69

摘要:

分析了经验模式分解的滤波性能;针对旋转机械振动信号信噪比低及非平稳特性,应用经验模式分解对振动信号进行降噪处理,突出了有用振动信号,为旋转机械在线监测和故障诊断提供了有效的依据;仿真实验及真实数据分析表明,经验模式分解在振动信号降噪处理中是有效的,为振动信号分析提供了新的方法。

关键词: 故障诊断     经验模式分解     旋转机械     滤波    

Anovel approach of noise statistics estimate using H∞ filter in target tracking

Xie WANG,Mei-qin LIU,Zhen FAN,Sen-lin ZHANG

《信息与电子工程前沿(英文)》 2016年 第17卷 第5期   页码 449-457 doi: 10.1631/FITEE.1500262

摘要: Noise statistics are essential for estimation performance. In practical situations, however, a priori information of noise statistics is often imperfect. Previous work on noise statistics identification in linear systems still requires initial prior knowledge of the noise. A novel approach is presented in this paper to solve this paradox. First, we apply the H∞ filter to obtain the system state estimates without the common assumptions about the noise in conventional adaptive filters. Then by applying state estimates obtained from the H∞ filter, better estimates of the noise mean and covariance can be achieved, which can improve the performance of estimation. The proposed approach makes the best use of the system knowledge without a priori information with modest computation cost, which makes it possible to be applied online. Finally, numerical examples are presented to show the efficiency of this approach.

关键词: Noise estimate     H∞     filter     Target tracking    

珊瑚岛礁环境噪声成像 Article

夏少红, 张昌榕, 曹敬贺

《工程(英文)》 2023年 第25卷 第6期   页码 182-193 doi: 10.1016/j.eng.2021.09.022

摘要:

As valuable land in the ocean, coral islands are not only important bases for making use of marine resources and protecting marine rights and interests, but also important for breakthrough research in many fields of earth science. Hence, the economical and efficient determination of the underground structure of coral islands has become significant in coral island engineering geology, but remains challenging for traditional marine geophysical prospecting and drilling methods. While ambient noise tomography with dense arrays has been widely used in continental regions, its applicability to coral islands remains undetermined. In this study, based on the data recorded by a dense array on an isolated coral island in the South China Sea, we analyzed the ambient noise characteristics and obtained a 3D subsurface structure of the coral island using ambient noise tomography. We made the following findings: ① The ambient noise frequencies can be roughly categorized into three levels: < 1, 1–5, and > 5 Hz. The spectral characteristics of the noise below 5 Hz were consistent at different stations, but there were significant differences in the characteristics of the noise above 5 Hz. ② For ambient noise frequencies below 5 Hz, cross-correlation functions with high quality could be obtained with only 24 h of waveform data. However, it was difficult to extract meaningful cross-correlation functions for ambient noise frequencies above 5 Hz. ③ The S-wave velocity in the coral island was higher toward the sea and lower toward the lagoon, which was consistent with the high degree of cementation of the outer reef flat stratum on the seaward side. ④ There were two low-velocity horizons at 25–75 and 200–300 m, which were in good agreement with the high-porosity horizons that were revealed by drilling core samples, reflecting the weathering history of the reef. Our research demonstrates that ambient noise tomography is a potentially economical, efficient, and environmentally friendly method for the geological prospecting of coral reefs.

关键词: Coral island     Ambient noise tomography     Engineering geology     South China Sea    

Investigation of flow dynamics and decrease of vortex noise inside volute of centrifugal fans

LI Chunxi, WANG Songling

《能源前沿(英文)》 2008年 第2卷 第2期   页码 235-240 doi: 10.1007/s11708-008-0040-3

摘要: The characteristics of three-dimension flow dynamics inside the volute of a G4-73No.8D centrifugal fan was simulated numerically using a computational fluid dynamics(CFD) technique. The generation, evolution, and noise of the vortex were investigated when cylinder-shaped and cone-cylinder-shaped anti-vortex rings were added separately. Numerical results showed that large-scale vortices were broken effectively and the flow fields inside the fan were more uniform with the two anti-vortex rings installed. Experimental results indicated A-sound level and spectrum noise of the refitted fan decreased and the two anti-vortex rings were effective in decreasing vortex noise. The cone-cylinder-shaped anti-vortex ring was more effective than the cylinder-shaped one in breaking large-scale vortexes and decreasing vortex noise.

关键词: cylinder-shaped     evolution     computational     effective     large-scale    

Integrated virtual-design methods for forecasting radiated noise of single cylinder diesel block

GUO Lei, HAO Zhiyong, XU Hongmei, LIU Lianyun

《能源前沿(英文)》 2008年 第2卷 第4期   页码 416-421 doi: 10.1007/s11708-008-0097-z

摘要: The two cycle dynamical results, such as the bearing load, the piston thrust, and the load spatial distribution etc., were obtained by hybrid dynamical simulation of the flexible assembly of the block and crank-train. The finite element model of the block was validated by modal test. The frequency response of the block was calculated using the finite element method (FEM). Finally, the radiated noise such as sound power level and efficiency in the out sound field were obtained using the direct boundary element method (BEM).

关键词: bearing     dynamical     frequency response     dynamical simulation     hybrid dynamical    

of structural responses using an optimal passive tuned mass damper under stationary Gaussian white noise

Min-Ho CHEY, Jae-Ung KIM

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 267-280 doi: 10.1007/s11709-012-0170-x

摘要: In this study, the structural control strategy utilizing a passive tuned mass damper (TMD) system as a seismic damping device is outlined, highlighting the parametric optimization approach for displacement and acceleration control. The theory of stationary random processes and complex frequency response functions are explained and adopted. For the vibration control of an undamped structure, the optimal parameters of a TMD, such as the optimal tuning frequency and optimal damping ratio, to stationary Gaussian white noise acceleration are investigated by using a parametric optimization procedure. For damped structures, a numerical searching technique is used to obtain the optimal parameters of the TMD, and then the explicit formulae for these optimal parameters are derived through a sequence of curve-fitting schemes. Using these specified optimal parameters, several different controlled responses are examined, and then the displacement and acceleration based control effectiveness indices of the TMD are examined from the view point of RMS values. From the viewpoint of the RMS values of displacement and acceleration, the optimal TMDs adopted in this study shows clear performance improvements for the simplified model examined, and this means that the effective optimization of the TMD has a good potential as a customized target response-based structural strategy.

关键词: tuned mass damper     parametric optimization     passive control     white noise     earthquake excitation    

Multi-UAV cooperative target tracking with bounded noise for connectivity preservation

Rui Zhou, Yu Feng, Bin Di, Jiang Zhao, Yan Hu,jzhao@buaa.edu.cn

《信息与电子工程前沿(英文)》 2020年 第21卷 第10期   页码 1413-1534 doi: 10.1631/FITEE.1900617

摘要: We investigate cooperative target tracking of multiple unmanned aerial vehicles (UAVs) with a limited communication range. This is an integration of UAV motion control, target state estimation, and network topology control. We first present the communication topology and basic notations for , and introduce the distributed . Then, convergence and boundedness of the estimation errors using the filter are analyzed, and potential functions are proposed for communication link maintenance and collision avoidance. By taking stable target tracking into account, a distributed potential function based UAV motion controller is discussed. Since only the estimation of the target state rather than the state itself is available for UAV motion control and UAV motion can also affect the accuracy of state estimation, it is clear that the UAV motion control and target state estimation are coupled. Finally, the stability and convergence properties of the coupled system under are analyzed in detail and demonstrated by simulations.

Numerical analysis of aerodynamic noise radiated from cross flow fan

CHEN Anbang, LI Song, HUANG Dongtao

《能源前沿(英文)》 2008年 第2卷 第4期   页码 443-447 doi: 10.1007/s11708-008-0063-9

摘要: The flow field in a cross flow fan was simulated by solving the 2-D unsteady Reynolds-averaged Navier-Stokes equations. The calculated pressure fluctuations of the blades, the vortex wall, and the rear wall were then used as noise sources to calculate the sound field. The Ffowcs Williams-Hawkings (FW-H) equation was employed to predict the noise field caused by these sources. The predictions show that the rear wall and the vortex wall sources contribute significantly to the total noise and that both the predicted aerodynamic performance and noise agree well with the experimental results.

关键词: predicted aerodynamic     Williams-Hawkings     calculated pressure     aerodynamic performance     unsteady Reynolds-averaged    

Air-borne noise of thermal module and system for notebook personal computers: experimental study

SHI Junye, JIANG Cailing, QIAO Junsheng, CHEN Jiangpin, LI Xiaoping, ZHANG Xiaojun

《能源前沿(英文)》 2008年 第2卷 第2期   页码 174-178 doi: 10.1007/s11708-008-0034-1

摘要: Thermal performance is the most important issue to be considered when a thermal module is designed for a notebook personal computer (PC). Because the fan causes air-borne noise and affects the user’s comfort, the acoustic characteristics of the module attract more attention. Experiments were conducted to study the noise sources, the noise characteristic and the main factors influencing the noise level. The difference between the air-borne noise of the thermal module and the whole computer system was analyzed and its propagating characteristics were derived. The influence of I/O ports on the air-borne noise was also studied experimentally.

关键词: air-borne     attention     propagating     characteristic     personal computer    

3D finite element analysis of composite noise barrier constructed of polyurethane products

Ben DAEE,Hesham El NAGGAR

《结构与土木工程前沿(英文)》 2017年 第11卷 第1期   页码 100-110 doi: 10.1007/s11709-016-0364-8

摘要: This paper presents a numerical investigation on the structural performance of an innovative noise barrier consisting of poly-block, rigid polyurethane foam (RPF) and polyurea. The mechanical characteristics of RPF as well as the flexural resistance of the proposed wall system (poly-wall) were established and presented in another study. The experimental results are used in the current study to develop, calibrate and verify 3D finite element (FE) models of the wall system. The components of the poly-wall including steel rebars, poly-blocks and RPF cores were simulated and then verified using the results of experiments conducted on the wall components. The results of numerical analysis exhibited a satisfactory agreement with the experimental outcomes for the entire wall system. The verified numerical models were then used to conduct a parametric study on the performance of poly-wall models under uniform wind load and gravity load. The findings of the current study confirmed that the structural performance of poly-wall is satisfactory for noise barrier application. Simulation techniques for improvement of the numerical analysis of multi-martial 3D FE models were discussed.

关键词: 3D finite element     sound wall     rigid polyurethane foam     poly-wall     numerical model     calibration    

Embracing digital mindsets to ensure a sustainable future

《环境科学与工程前沿(英文)》 2023年 第18卷 第3期 doi: 10.1007/s11783-024-1799-0

关键词: Wildlife     Climate Change     Heavy metals     Noise     LAN     Light pollution    

标题 作者 时间 类型 操作

Design of noise-reduction seats for high-speed trains

Xiaojun DENG, Yanju ZHAO, Haijin ZHANG, Renzhong SHUAI, Leiwei ZHU

期刊论文

Application of python-based Abaqus preprocess and postprocess technique in analysis of gearbox vibration and noisereduction

Guilian YI, Yunkang SUI, Jiazheng DU

期刊论文

Noise reduction for centrifugal fan with non-isometric forward-swept blade impeller

MA Jianfeng, QI Datong, MAO Yijun

期刊论文

A fully solid-state cold thermal energy storage device for car seats using shape-memory alloys

期刊论文

基于经验模式分解的旋转机械振动信号降噪处理

杨建文,贾民平,许飞云,胡建中

期刊论文

Anovel approach of noise statistics estimate using H∞ filter in target tracking

Xie WANG,Mei-qin LIU,Zhen FAN,Sen-lin ZHANG

期刊论文

珊瑚岛礁环境噪声成像

夏少红, 张昌榕, 曹敬贺

期刊论文

Investigation of flow dynamics and decrease of vortex noise inside volute of centrifugal fans

LI Chunxi, WANG Songling

期刊论文

Integrated virtual-design methods for forecasting radiated noise of single cylinder diesel block

GUO Lei, HAO Zhiyong, XU Hongmei, LIU Lianyun

期刊论文

of structural responses using an optimal passive tuned mass damper under stationary Gaussian white noise

Min-Ho CHEY, Jae-Ung KIM

期刊论文

Multi-UAV cooperative target tracking with bounded noise for connectivity preservation

Rui Zhou, Yu Feng, Bin Di, Jiang Zhao, Yan Hu,jzhao@buaa.edu.cn

期刊论文

Numerical analysis of aerodynamic noise radiated from cross flow fan

CHEN Anbang, LI Song, HUANG Dongtao

期刊论文

Air-borne noise of thermal module and system for notebook personal computers: experimental study

SHI Junye, JIANG Cailing, QIAO Junsheng, CHEN Jiangpin, LI Xiaoping, ZHANG Xiaojun

期刊论文

3D finite element analysis of composite noise barrier constructed of polyurethane products

Ben DAEE,Hesham El NAGGAR

期刊论文

Embracing digital mindsets to ensure a sustainable future

期刊论文