Loss Factors and their Effect on Resonance Peaks in Mechanical Systems

The loss factors and their effects on the magnitude and frequency of resonance peaks in various mechanical sys-tems are reviewed for acoustic,vibration,and vibration fatigue applications.The main trends and relationships were obtained for linear mechanical models with hysteresis damping.The well-known features(complex module of elasticity,total loss factor,etc.)are clarified for practical engineers and students,and new results are presented(in particular,for 2-DOF in-series models with hysteresis friction).The results are of both educational and prac-tical interest and may be applied for NVH analysis and testing,mechanical and aeromechanical design,and noise and vibration control in buildings.

Research on Narrowband Line Spectrum Noise Control Method Based on Nearest Neighbor Filter and BP Neural Network Feedback Mechanism

Thefilter-x least mean square(FxLMS)algorithm is widely used in active noise control(ANC)systems.However,because the algorithm is a feedback control algorithm based on the minimization of the error signal variance to update thefilter coefficients,it has a certain delay,usually has a slow convergence speed,and the system response time is long and easily affected by the learning rate leading to the lack of system stability,which often fails to achieve the desired control effect in practice.In this paper,we propose an active control algorithm with near-est-neighbor trap structure and neural network feedback mechanism to reduce the coefficient update time of the FxLMS algorithm and use the neural network feedback mechanism to realize the parameter update,which is called NNR-BPFxLMS algorithm.In the paper,the schematic diagram of the feedback control is given,and the performance of the algorithm is analyzed.Under various noise conditions,it is shown by simulation and experiment that the NNR-BPFxLMS algorithm has the following three advantages:in terms of performance,it has higher noise reduction under the same number of sampling points,i.e.,it has faster convergence speed,and by computer simulation and sound pipe experiment,for simple ideal line spectrum noise,compared with the convergence speed of NNR-BPFxLMS is improved by more than 95%compared with FxLMS algorithm,and the convergence speed of real noise is also improved by more than 70%.In terms of stability,NNR-BPFxLMS is insensitive to step size changes.In terms of tracking performance,its algorithm responds quickly to sudden changes in the noise spectrum and can cope with the complex control requirements of sudden changes in the noise spectrum.

Research on Human-Vehicle-Road Friendliness Based on Improved SH-GH-ADD Control

The hub-driven virtual rail train is a novel urban transportation system that amalgamates the benefits of modern trams and buses.However,this system is plagued by issues such as decreased ride comfort and severe deformation of urban roads due to the increase in sprung mass and long-term rolling at the same position.To address these concerns and improve the human-vehicle-road friendliness of the virtual rail train,we propose an Improved Sky-Ground Hook and Acceleration-Driven Damper control(Improved SH-GH-ADD control)strategy for the semi-active suspension system.This control monitors the vibration acceleration signal of the unsprung mass in real-time and selects the mixed Sky-Hook and Acceleration-Driven Damper(SH-ADD)control or the mixed Ground-Hook and Acceleration-Driven Damper(GH-ADD)control based on the positive and negative values of the vibration acceleration of the unsprung mass.The Improved SH-GH-ADD control combines the advantages of SH-ADD control and GH-ADD control to achieve control of the sprung mass and unsprung mass in the full fre-quency band.Finally,through simulation and comparative analysis with traditional SH-ADD,GH-ADD,and mixed SH-GH control,we demonstrate the exceptional performance of the proposed algorithm.

Adaptive Multi-Feature Fusion for Vehicle Micro-Motor Noise Recognition Considering Auditory Perception

The deployment of vehicle micro-motors has witnessed an expansion owing to the progression in electrification and intelligent technologies.However,some micro-motors may exhibit design deficiencies,component wear,assembly errors,and other imperfections that may arise during the design or manufacturing phases.Conse-quently,these micro-motors might generate anomalous noises during their operation,consequently exerting a substantial adverse influence on the overall comfort of drivers and passengers.Automobile micro-motors exhibit a diverse array of structural variations,consequently leading to the manifestation of a multitude of distinctive auditory irregularities.To address the identification of diverse forms of abnormal noise,this research presents a novel approach rooted in the utilization of vibro-acoustic fusion-convolutional neural network(VAF-CNN).This method entails the deployment of distinct network branches,each serving to capture disparate features from the multi-sensor data,all the while considering the auditory perception traits inherent in the human auditory sys-tem.The intermediary layer integrates the concept of adaptive weighting of multi-sensor features,thus affording a calibration mechanism for the features hailing from multiple sensors,thereby enabling a further refinement of features within the branch network.For optimal model efficacy,a feature fusion mechanism is implemented in the concluding layer.To substantiate the efficacy of the proposed approach,this paper initially employs an augmented data methodology inspired by modified SpecAugment,applied to the dataset of abnormal noise sam-ples,encompassing scenarios both with and without in-vehicle interior noise.This serves to mitigate the issue of limited sample availability.Subsequent comparative evaluations are executed,contrasting the performance of the model founded upon single-sensor data against other feature fusion models reliant on multi-sensor data.The experimental results substantiate that the suggested methodology yields heightened recognition accuracy and greater resilience against interference.Moreover,it holds notable practical significance in the engineering domain,as it furnishes valuable support for the targeted management of noise emanating from vehicle micro-motors.

Multi-Objective Prediction and Optimization of Vehicle Acoustic Package Based on ResNet Neural Network

Vehicle interior noise has emerged as a crucial assessment criterion for automotive NVH(Noise,Vibration,and Harshness).When analyzing the NVH performance of the vehicle body,the traditional SEA(Statistical Energy Analysis)simulation technology is usually limited by the accuracy of the material parameters obtained during the acoustic package modeling and the limitations of the application conditions.In order to effectively solve these shortcomings,based on the analysis of the vehicle noise transmission path,a multi-level objective decomposition architecture of the interior noise at the driver’s right ear is established.Combined with the data-driven method,the ResNet neural network model is introduced.The stacked residual blocks avoid the problem of gradient dis-appearance caused by the increasing network level of the traditional CNN network,thus establishing a higher-precision prediction model.This method alleviates the inherent limitations of traditional SEA simulation design,and enhances the prediction performance of the ResNet model by dynamically adjusting the learning rate.Finally,the proposed method is applied to a specific vehicle model and verified.The results show that the proposed meth-od has significant advantages in prediction accuracy and robustness.

A Method of Evaluating the Effectiveness of a Hydraulic Oscillator in Horizontal Wells

Bent-housing motor is the most widely used directional drilling tool,but it often encounters the problem of high friction when sliding drilling in horizontal wells.In this paper,a mathematical model is proposed to simulate slide drilling with a friction reduction tool of axial vibration.A term called dynamic effective tractoring force(DETF)is defined and used to evaluate friction reduction effectiveness.The factors influencing the DETF are studied,and the tool placement optimization problem is investigated.The studyfinds that the drilling rate of penetration(ROP)can lower the DETF but does not change the trend of the DETF curve.To effectively work,the shock tool stiffness must be greater than some critical value.For the case study,the best oscillating frequency is within 15∼20 Hz.The reflection of the vibration at the bit boundary can intensify or weaken the friction reduction effec-tiveness,depending on the distance between the hydraulic oscillator and the bit.The optimal placement position corresponds to the plateau stage of the DETF curve.The reliability of the method is verified by thefield tests.The proposed method can provide a design and use guide to hydraulic oscillators and improve friction reduction effectiveness in horizontal wells.

Research on Stick-Slip Vibration Suppression Method of Drill String Based on Machine Learning Optimization

During the drilling process,stick-slip vibration of the drill string is mainly caused by the nonlinear friction gen-erated by the contact between the drill bit and the rock.To eliminate the fatigue wear of downhole drilling tools caused by stick-slip vibrations,the Fractional-Order Proportional-Integral-Derivative(FOPID)controller is used to suppress stick-slip vibrations in the drill string.Although the FOPID controller can effectively suppress the drill string stick-slip vibration,its structure isflexible and parameter setting is complicated,so it needs to use the cor-responding machine learning algorithm for parameter optimization.Based on the principle of torsional vibration,a simplified model of multi-degree-of-freedom drill string is established and its block diagram is designed.The continuous nonlinear friction generated by cutting rock is described by the LuGre friction model.The adaptive learning strategy of genetic algorithm(GA),particle swarm optimization(PSO)and particle swarm optimization improved(IPSO)by arithmetic optimization(AOA)is used to optimize and adjust the controller parameters,and the drill string stick-slip vibration is suppressed to the greatest extent.The results show that:When slight drill string stick-slip vibration occurs,the FOPID controller optimized by machine learning algorithm has a good effect on suppressing drill string stick-slip vibration.However,the FOPID controller cannot get the drill string system which has fallen into serious stick-slip vibration(stuck pipe)out of trouble,and the machine learning algorithm is required to mark a large amount of data on adjacent Wells to train the model.Set a reasonable range of drilling parameters(weight on bit/drive torque)in advance to avoid severe stick-slip vibration(stuck pipe)in the drill string system.

Study of Axial Vibration of a Motor-Compressor System Using Operational Modal Analysis

A case study of excessive vibration on a motor-compressor system is presented in this paper.After barely two months of operation,the reciprocating compressor motor’s routine monitoring revealed excessive axial vibration amplitude.For this reason,the Operational Modal Analysis(OMA)was carried out in order to identify the pri-mary cause.According to the investigation,one of the harmonic components which was 18 times the motor’s running speed matched with a resonance frequency of 112 Hz.According to OMA study,the motor was vibrating in torsional motion because the compressor’s load had stimulated the entire motor-compressor unit at this reso-nance frequency.The analysis also demonstrates the bulging effect of the motor shaft’s axial vibration on the motor’s endplate.

Introduction to the Special Issue on Perspectives on Soundscape and Challenges of Noise Pollution: A Multidisciplinary Approach to Sustainable Environmental Solutions

Over the past two decades,research on the subject of noise pollution and urban soundscapes has seen significant growth[1,2].The goal of these studies was to gain a better understanding of the urban acoustic environment by employing various methodologies and techniques to delve into the complexity of this topic.These research efforts have primarily revolved around two fundamental axes[3].On one hand,the first axis focused on combating noise pollution[4–6],emphasizing the reduction of unwanted sounds and compliance with sound levels set by environmental and health protection organizations[7,8].

Introduction to the Special Issue on Passive and Active Noise Control for Vehicle

The new generation of road vehicles is undergoing rapid advancements towards electrification,intelligence,inter-connection and sharing.Besides being a means of transportation,vehicles are expected to have more functions,such as work and entertainment.In line with these trends,vehicle interior noise control deserves renewed attention beyond traditional approaches such as just controlling physical acoustic quantities.The last decade has witnessed revolutionary progress in materials,structures,control methods and technologies that create a quieter and more comfortable interior sound environment for vehicles.However,prevalent challenges remain,notably the intense time-varying and nonlinear characteristics of interior noise generated in the running vehicle,especially under high-speed driving conditions.

生活中的信仰——河西走廊东部民间道教仪式音声田野纪实

河西走廊东部民间道教仪式活动与民众生活密切相关,民间道教信仰成为人们生活的一部分。本文以民间道士主持的葬礼仪式、谢土仪式为个案,较详细描述了道士在仪式中的音声行为与表演行为。仪式过程中,音声结构与仪式结构密切相关,民间道士在仪式各个环节中的“权威性”得到充分体现。道教音乐“曲库”的积累,既是一个不断变化与丰富发展的过程,也是一个不断“与时俱进”的过程。

国民政府对民间婚丧礼俗的管理研究——以丧葬音乐为例(1927—1937)

民国初期,丧葬礼俗依然延续了前代的形式,其中一些封建迷信、奢侈浪费的行为,成为时代发展的制约,国民政府陆续对婚丧礼俗进行了管理。这些管理主要从1934年开始,至1937年结束,为期4年,经历了5个阶段:1934年颁布《公务人员革除婚丧寿宴浪费暂行规程》,1936年颁布《婚丧仪仗暂行办法》,1936年、1937年各省颁布《婚丧仪仗施行细则》,1937年成立乐典编订委员会对婚丧礼俗音乐审核,1937年新生活运动促进会在其刊物上刊发了一系列的关于《婚丧礼俗调查与改革》的文章。这5个阶段是由新生活运动引发的,与新生活运动密切相关。经过改革,丧葬音乐与前代相比,有了重大的变化,即在政府层面上,音乐允许在国礼中存在,而以往,国家丧葬礼制中不能有音乐存在,这是民国时期丧葬礼俗改革的最大亮点。但除了音乐,整体礼俗的改革结果——礼俗的变化很小,很多习俗依然没有变化,这跟改革的不彻底性、中国人的孝道观以及礼俗的稳定性相关。

由礼谈和:泉州南音“和”乐观探究

本文以泉州南音乐人“和”乐观为切入点,通过存见于泉州南音中的相关礼节加以展开,从祭仪之“礼”、展演之“礼”,再到人与人之间的“礼节”,试图通过对“礼”的解析,挖掘深藏于南音表演实践背后的礼乐规范,解析泉州南音乐人的作乐思维,以求对该乐种有深层次的理解。

评《噪音起义:一场世界性音乐革命的声音政治》

在《噪音起义:一场世界性音乐革命的声音政治》一书中,迈克·丹宁1(Michael Denning)从文化历史学的视角出发,展现了1925年到1930年间一幅全球性的历史音景。随着留声机录音技术的出现,成百上千的无名音乐人在不同殖民港口城市的简陋录音棚里录制了无数当地城市街区和舞厅中的音乐,例如里约的桑巴、新奥尔良的爵士、布宜诺斯艾利斯的探戈,以及加尔各答的克隆钟。这些音乐也引发了第一次全球性的流行音乐革命,并成为伴随并记录这段反殖民历史的重要音轨。

彝族苏尼的口述史研究——以吉木苏尼为例

本文是对凉山布拖彝族阿都“苏尼”1吉木子聪的访谈,访谈以苏尼吉木子聪的个人经历和其做尼的仪式过程为主题,探讨总结了他做尼12年以来的仪式历程,分析出做尼不仅是一种巫术,以巫乐的形式对当地彝族人“行医”治愈;而且也是一种梳理彝族苏尼历史图谱和解读阶级结构的活的口述史;更是以歌舞乐的整体形式对彝族现代音乐有新的启示。

重塑梁溪清音——无锡天韵社现状考察

无锡天韵社是创始于明代末年的文人清唱曲社。从最早的曲局,到后来的天韵社,历经300余年,社员们始终秉持“梁溪清音”的文人曲唱风范。2013年年末,无锡的昆曲爱好者借“天韵社”之名,成立了新的昆曲社。复社之初,社员们因共同的兴趣爱好,定期地聚集在一起拍曲吟唱。然而,不断萌发的文化自觉意识使社员们尝试沟通历史与当下,希冀在祭奠仪式中,在追寻曲唱规范中,在发现、整理、发行传承曲谱中,对历史上的天韵社深度挖掘和精神继承。文章以法国学者哈布瓦赫的“集体记忆”为主要理论,阐释新天韵社如何以曲社为记忆框架,以“天韵社”三字为精神符号,并且通过实践对老天韵社的历史进行建构与继承。

一种春声忘不得——杨荫浏与郝路义

19世纪末20世纪初,美国新教圣公会团(The American Protestant Episcopal Mission)向中国派遣传教士,总部设在上海,传教点分布于无锡、南京等地。这其中有一位叫作郝路义(Louis Strong Hammond)的传教士旅居中国长达30余年,她擅键盘乐器,通晓作曲技术理论,对中国音乐特别是江南词乐颇有研究。年轻时的杨荫浏幸运地遇到了这位慈爱的外国音乐老师,把新型音乐知识送进家门。14岁的少年在家门口遇到了外教,不但听到了另一种音乐,也在艰难时世中获得了中西文化碰撞时的应变之策与清醒判断。幸遇隽彦,丝染日深,涵养西学,开阔胸襟。中外互补让伴随“五四”精神成长起来的人,享受到点点滴滴落到实处的恩惠。没有她的引领,杨荫浏不会成为现代意义上具有双重知识谱系的音乐学家。

中国民间古典音乐巡回演出团巡演纪事

成立于1954年10月27日、历时3个月在全国十余个城市巡演104场的中国民间古典音乐巡回演出团,曾产生过深远的影响。本文将其作为研究对象,对巡演过程进行系统梳理,为集民间和古典音乐展示、中央和地方文化交流、乐器制作与演奏方法改良于一体、具有典型意义的历史事件,提供真实立体的依据。

阳高南路晋北鼓乐的仪式音乐传承

晋北阳高南部等地的“晋北鼓乐(阳高南路)1杨家班”在音乐风格和传承方式上,与其他路鼓乐相比,都显得更为古老和独具特色。在当前仪式音乐生态普遍简单化与俗化的时代变迁中,杨家班的成员仍然坚持着自己对“鼓乐”和“鼓匠”的理解,这为我们对晋北鼓乐的深入研究提供了一个很好的范例,也为传统仪式音乐如何走出危机提供了新的研究资料。

“从润到韵”与乐间入门——双重地方作乐传统背景下的甲子八音

粤东海陆丰地区甲子镇北栅社区的民间乐种“甲子八音”(又名“福建八音”),有其独特的音乐审美观——“润”,并由此形成甲子八音的音乐之“韵”。这与当地乐人对甲子镇上存在的另一种合奏乐形式——潮州弦诗乐“欣赏不来”或“没有兴趣”,且认为只有甲子八音才具有“古”“雅”的审美风格形成较为明显的差异。本文将从甲子八音乐人的习乐经历和作乐感受中,寻找这一乐种隐含于乐人群体中的音乐文化价值内核。