Volume 1: Acoustics, Vibration, and Phononics最新文献

{"title":"Development and Characterization of Fly Ash Nanoparticles Reinforced Epoxy Resin Composite for Acoustic Applications","authors":"K. Ukoba, S. Popoola, O. Israel, Patrick Ehi Imoisili, T. Jen","doi":"10.1115/IMECE2020-23708","DOIUrl":"https://doi.org/10.1115/IMECE2020-23708","url":null,"abstract":"\u0000 Noise is an unwanted sound; requires reduction and control through the use of absorptive materials. This is imperative due to the adverse effect noise poses to human health, knowledge dissemination, and tranquility which is increasing daily due to industrialization and heightened allied activities. The use of natural and synthetic reinforced composites in noise pollution control is an emerging area of research. This study aims to develop and characterize fly ash nanoparticles reinforced epoxy resin composite for acoustic applications. Samples were prepared with fly ash nanoparticles reinforcement at 5%, 10%, 15%, 20%, and 25% and investigation of noise reduction coefficient (NRC), porosity and mechanical properties (hardness, impact, flexural strength) of samples were done. Cenospheres were obtained when fly ash particles were characterized separately with the aid of sieve analysis and x-ray fluorescence analysis. The cenospheres are hollow spherical and lightweight, inertfiller material. Correlation between porosity of the samples and their sound absorption properties was observed and showed that as porosity increased, the NRC values increased and as the porosity decreased the NRC values decreased. It was also observed that heat of polymerization, fly ash nanoparticles structure and air bubbles during sample preparation (mixing) influenced the porosity values which in turn influenced the NRC values of the composite. There was also a steady decrease in mechanical properties, as reinforcements were added (5%, 10%, 15%, 20%, and 25%), this was attributed to the high surface areas and shape of reinforcement added.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"9 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81909646","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}

{"title":"Microwave Induced Thermoacoustic Imaging With Multi-Pulse in Geological Application","authors":"Xu Mao, Chang Liu, Chang Wang, J. Heredia-Juesas, J. Martinez-Lorenzo","doi":"10.1115/IMECE2020-24609","DOIUrl":"https://doi.org/10.1115/IMECE2020-24609","url":null,"abstract":"\u0000 The accurate and real-time monitoring of fluid flow in porous media can boost the prediction of mass transport and chemical reactions, which profoundly impacts the subsurface exploration and hydrocarbon extractions. Our preliminary effort has shown the efficacy of employing a thermoacoustic (TA) technology for imaging an immobile rock sample. The results support the applicability of making this methodology to move forward for imaging a dynamical process. But the real-time monitoring of fluid flow requires the target under test to excite TA signals with a higher signal-to-noise ratio (SNR), which will promise a sufficient image resolution with fewer necessary measurements or less averaged times, and then lead to a faster scan. It is proved that the excitation pulse is directly proportional to the microwave absorption rate, and thus determines the observability of the corresponding TA signals. Unfortunately, due to the thermal and stress confinements, a microsecond-width pulse envelope is greatly limited and is not sufficient for achieving a high SNR. Although a recently proposed Frequency Modulation Continuous Wave (FMCW) showed an improvement on SNR, it signifies a deficiency of the long-time irradiation and additional electronic disturbance especially at a high peak power. To address this issue, we propose a new excitation envelope with multi-pulses, to favor the coherent frequency-domain signaling method for optimizing the image reconstruction while shortening the total envelope duration than that of the FMCW. In the present paper, the TA sensing of a dry sandstone sample is presented, which efficiently enhances the SNR of TA signals and the image resolution, thus validating the appropriateness of the proposed multi-pulse envelope. The current study also promises a future possibility towards its application for dynamically exploring the underground flow transport.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90781631","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}

{"title":"Dynamics of Piezo-Embedded Negative Stiffness Mechanical Metamaterials: A Study on Electromechanical Bandgaps","authors":"A. Dwivedi, A. Banerjee, B. Bhattacharya","doi":"10.1115/IMECE2020-23717","DOIUrl":"https://doi.org/10.1115/IMECE2020-23717","url":null,"abstract":"\u0000 Dynamics of periodic materials and structures have a profound historic background starting from Newton’s first effort to find sound propagation in the air to Rayleigh’s exploration of continuous periodic structures. This field of interest has received another surge from the early 21st century. Elastic mechanical metamaterials are the exemplars of periodic structures that exhibit interesting frequency-dependent properties like negative Young’s modulus, negative mass and negative Poisson’s ratio in a specific frequency band due to additional feature of local resonance. In this research, we present the modeling of piezo-embedded negative stiffness metamaterials by considering a shunted inductor energy harvesting circuit. For a chain of a finite number of metamaterial units, the coupled equation of motion of the system is deduced using generalized Bloch’s theorem. Successively, the backward substitution method is applied to compute harvested power and the transmissibility of the system. Additionally, through the extensive non-dimensional study of this system, the proposed metamaterial band structure is investigated to perceive locally resonant mechanical and electromechanical bandgaps. The results explicate that the insertion of the piezoelectric material in the resonating unit provides better tun-ability for vibration attenuation and harvested energy.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88579438","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}

{"title":"Medium Frequency Vibration Analysis of Beam Structures Modeled by the Timoshenko Beam Theory","authors":"Yichi Zhang, Bingen Yang","doi":"10.1115/IMECE2020-23098","DOIUrl":"https://doi.org/10.1115/IMECE2020-23098","url":null,"abstract":"\u0000 Vibration analysis of complex structures at medium frequencies plays an important role in automotive engineering. Flexible beam structures modeled by the classical Euler-Bernoulli beam theory have been widely used in many engineering problems. A kinematic hypothesis in the Euler-Bernoulli beam theory is that plane sections of a beam normal to its neutral axis remain normal when the beam experiences bending deformation, which neglects the shear deformation of the beam. However, as observed by researchers, the shear deformation of a beam component becomes noticeable in high-frequency vibrations. In this sense, the Timoshenko beam theory, which describes both bending deformation and shear deformation, may be more suitable for medium-frequency vibration analysis of beam structures.\u0000 This paper presents an analytical method for medium-frequency vibration analysis of beam structures, with components modeled by the Timoshenko beam theory. The proposed method is developed based on the augmented Distributed Transfer Function Method (DTFM), which has been shown to be useful in various vibration problems. The proposed method models a Timoshenko beam structure by a spatial state-space formulation in the s-domain, without any discretization. With the state-space formulation, the frequency response of a beam structure, in any frequency region (from low to very high frequencies), can be obtained in an exact and analytical form. One advantage of the proposed method is that the local information of a beam structure, such as displacements, bending moment and shear force at any location, can be directly obtained from the space-state formulation, which otherwise would be very difficult with energy-based methods. The medium-frequency analysis by the augmented DTFM is validated with the FEA in numerical examples, where the efficiency and accuracy of the proposed method is present. Also, the effects of shear deformation on the dynamic behaviors of a beam structure at medium frequencies are illustrated through comparison of the Timoshenko beam theory and the Euler-Bernoulli beam theory.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"10 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90616793","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}

{"title":"On the Passive Noise Control of the Flow-Induced Noise Using Porous Materials","authors":"Reon Nishikawa, O. Terashima, A. Inasawa","doi":"10.1115/IMECE2020-24483","DOIUrl":"https://doi.org/10.1115/IMECE2020-24483","url":null,"abstract":"\u0000 A passive noise control technique for the flow-induced noise using a porous material was studied experimentally. The purpose of this study was to decrease the aerodynamic sound using porous material that permeated only sound and clarify that reduction mechanism. In the experiment, flow-induced noises emitted from two types of rectangular cylinders was measured in a low-noise wind tunnel. One cylinder was made of four aluminum plates and the other was two aluminum and porous material plates each. Measurement results show that the frequency of the distinct tonal noise was different between two cylinders, that frequency was higher for using porous material. It was also found that the sound pressure level of the noise was also different and that of the cylinder using porous material plate was 25 dB smaller at maximum. Velocity field of the wake of cylinders were examined by the PIV measurement and that showed that time and space scale of separated vortices around cylinder were smaller for using porous material. It is assumed that the change of aerodynamic sound was caused by that change in velocity field.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88235545","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}

{"title":"Ultrasonic Acoustic Heterodyne Transmission Into the Human Auditory and Vestibular Systems","authors":"C. Dumm, Anna C. Hiers, J. Vipperman, G. Klinzing, C. Balaban","doi":"10.1115/IMECE2020-24213","DOIUrl":"https://doi.org/10.1115/IMECE2020-24213","url":null,"abstract":"\u0000 It is well-known that airborne sound induces vibration of the eardrum, the coupled middle ear bones, and the inner ear. Sound transmission to the inner ear is attenuated by damage or dysfunction in the eardrum or ossicular chain. Corrective devices often use contact shakers to directly vibrate the temporal bone of the skull, delivering sound. We investigate an alternative, noncontact method of sound transmission that uses ultrasonic signals to transmit sound into the auditory and vestibular systems. Minimal literature exists describing ultrasonic hearing, largely due to attenuation of air-conducted frequencies above 20 kHz. High-amplitude airborne sound incident upon the skull can induce temporal bone system vibrations along an unconventional structural path. Finite-element-based acoustic modeling of the auditory and vestibular anatomy reveals resonant behavior in structural components of the middle and inner ear at ultrasonic frequencies. These “built-in sound amplifiers” can be leveraged to compensate for impedance mismatches experienced in airborne ultrasound transmission. By heterodyning (amplitude modulating) a targeted ultrasonic carrier signal with an audio signal, the nonlinearities of acoustic propagation and the auditory and vestibular sense organs allow interpretation of heterodyne signals. These techniques provide a foundation to improve a wide variety of communication equipment, including hearing aids, without interfering with balance sensations.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"199 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80057275","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}

{"title":"Multiphysics Simulation on Vibration and Noise of Variable-Speed Permanent Magnet Brushless DC Motor With Eccentricity","authors":"H. Niu, Yumin Xiao, Li Zhao, D. Roche, Yashu Li, M. Rosu, J. Gilmore","doi":"10.1115/IMECE2020-24289","DOIUrl":"https://doi.org/10.1115/IMECE2020-24289","url":null,"abstract":"\u0000 Multiphysics finite element modeling process is derived to predict vibration and noise due to magnetic forces within a permanent-magnet brushless DC motor over a variable speed range under healthy and eccentric faulty conditions. Transient analysis for magnetic force in two-dimensional electromagnetic model is carried out over a variable speed range. To keep cyclic symmetry mesh and avoid numerical source of noise, the method of effective air gap layer is applied and manipulated with relative permeability derived for static and dynamic eccentric rotating condition depending on rotation angle and eccentric shift. Using discrete Fourier transformation and electromagnetic-structural one-way coupling schemes, magnetic harmonic forces for a range of rotation angular speed are imported and applied on stator’s inner surfaces. Vibration characteristics are calculated for a three-dimensional full finite element model of the motor in harmonic response analysis. Finally, surface velocities are imported and applied on acoustic domain using fluid-structure interaction (FSI) one-way coupling. Noise radiated from motor housing including front and end caps is evaluated. The waterfall diagram of equivalent radiation pressure level (ERPL) and sound pressure level (SPL) contour plotting in function of rotation angular speed and frequency is obtained in multiple RPM harmonic structural and acoustic analyses. The vibro-acoustic feature pattern could be utilized in faulty detection.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"49 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88939910","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}

{"title":"Pulse Shaping in 1D Elastic Waveguides for Shock Testing","authors":"W. Johnson, M. Leamy, W. Delima, M. Ruzzene","doi":"10.1115/IMECE2020-23280","DOIUrl":"https://doi.org/10.1115/IMECE2020-23280","url":null,"abstract":"\u0000 Mechanical shock events experienced by electronics systems can be reproduced in the laboratory using Hopkinson bar tests. In these tests a projectile strikes a bar, creating a pulse which travels through the bar into the system. The quality of these tests depends on the closeness of the shape of the incident pulse to the shape specified for the test. This paper introduces a new way to control the shape of the incoming pulse, through the use of elastic metamaterial concepts. Two dispersion-modifying material concepts, phononic crystals, and local resonators, are examined for their wave shaping capabilities in 1D elastic waveguides. They are then evaluated using a transfer matrix method to determine the output wave shape in the time domain. The concepts are then optimized for various pulse shapes, showing that they are most effective when they are tuned to introduce dispersion near the fundamental frequency of the incident wave.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73992828","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}

{"title":"Microwave-Induced Thermoacoustic Compressive Imaging With Metamaterial Coding","authors":"Xu Mao, Chang Liu, J. Heredia-Juesas, J. Martinez-Lorenzo","doi":"10.1115/IMECE2020-24607","DOIUrl":"https://doi.org/10.1115/IMECE2020-24607","url":null,"abstract":"\u0000 The microwave-induced thermoacoustic (TA) sensing has been proven to promise a great potential in clinical and biomedical applications. This novel technology has also been explored to boost its use in subsurface geophysical applications. A conventional TA sensing system, however, is greatly limited by either a slow scan or a dramatical cost, and making infeasible the real-time monitoring when covering large domains. One remarkable solution of such issues is to design a compressive sensing (CS)-based TA system, with the aim of reducing the sampling intensity necessary to high resolution imaging. Specifically, to favor the demand for CS, this work studies the appropriateness of metamaterial (MM) resonators and proposes a MM linear array-coded TA system to randomize the transmitted acoustics waves. To prove the efficacy, images obtained from both of the proposed TA system and the conventional TA system without coding are assessed and compared. Under the same scenario, the MM-coded TA system shows higher imaging capabilities and a better performance when using a much-limited amount of measurements or in noisy enviornments. This method opens the door for a fast scan of the geological imaging and the real-time monitoring of the underground flow.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81131797","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}

{"title":"Steerable Unidirectional Wave Emission From a Single Piezoelectric Transducer Using a Shape Memory Alloy Composite Metasurface","authors":"Yihao Song, Yanfeng Shen","doi":"10.1115/IMECE2020-23460","DOIUrl":"https://doi.org/10.1115/IMECE2020-23460","url":null,"abstract":"\u0000 Structural Health Monitoring (SHM) and Nondestructive Evaluation (NDE) systems generally adopt piezoelectric transducers which emit omnidirectional wave fields. The achievement of directionality of guided wave generation will benefit the structural sensing purpose, which allows better detection and localization of the damage sites.\u0000 In this study, a type of metamaterial ultrasonic radar is proposed for the steerable unidirectional wave manipulation. It contains a circular array of unit cells stuck in an aluminum plate which are delicately arranged in a circular fashion. Each unit cell is composed of a shape memory alloy substrate and a lead stub. The controllable bandgap of such metamaterial system can be achieved due to the stiffness change of nitinol between its martensite phase and austenite phase under a thermal load. This research starts with a Finite Element Model (FEM) of the unit cell to compute its frequency-wavenumber domain dispersion characteristics, demonstrating the adjustable bandgap feature. Then, numerical modeling of the metamaterial radar is performed by shifting the bandgap of one sector of the metasurface away from the excitation frequency. The modeling results demonstrate that the martensite phase metasurface area forms a bandgap region where guided wave energy cannot penetrate, while the bandgap of the austenite sector shifts away from the excitation frequency, opening up a transmission path for the ultrasonic waves. By rotating the austenite sector, the metamaterial structure can work like a wave emission radar, realizing of the steerable unidirectional wave radiation with a single transducer. Such an active metasurface possesses great application potential in future SHM and NDE systems.","PeriodicalId":23648,"journal":{"name":"Volume 1: Acoustics, Vibration, and Phononics","volume":"36 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76078418","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}