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<!DOCTYPE html> <html lang="en" dir="ltr"> <head>  <script async src="https://www.googletagmanager.com/gtag/js?id=G-P63WKM1TM1"></script> <script> window.dataLayer = window.dataLayer || []; function gtag(){dataLayer.push(arguments);} gtag('js', new Date()); gtag('config', 'G-P63WKM1TM1'); </script>  <script type="text/javascript" > (function(m,e,t,r,i,k,a){m[i]=m[i]||function(){(m[i].a=m[i].a||[]).push(arguments)}; m[i].l=1*new Date(); for (var j = 0; j < document.scripts.length; j++) {if (document.scripts[j].src === r) { return; }} k=e.createElement(t),a=e.getElementsByTagName(t)[0],k.async=1,k.src=r,a.parentNode.insertBefore(k,a)}) (window, document, "script", "https://mc.yandex.ru/metrika/tag.js", "ym"); ym(55165297, "init", { clickmap:false, trackLinks:true, accurateTrackBounce:true, webvisor:false }); </script> <noscript><div><img src="https://mc.yandex.ru/watch/55165297" style="position:absolute; left:-9999px;" alt="" /></div></noscript>    <title>Search results for: M. Sasajima</title> <meta name="description" content="Search results for: M. Sasajima"> <meta name="keywords" content="M. Sasajima"> <meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1, user-scalable=no"> <meta charset="utf-8"> <link href="https://cdn.waset.org/favicon.ico" type="image/x-icon" rel="shortcut icon"> <link href="https://cdn.waset.org/static/plugins/bootstrap-4.2.1/css/bootstrap.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/plugins/fontawesome/css/all.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/css/site.css?v=150220211555" rel="stylesheet"> </head> <body> <header> <div class="container"> <nav class="navbar navbar-expand-lg navbar-light"> <a class="navbar-brand" href="https://waset.org"> <img src="https://cdn.waset.org/static/images/wasetc.png" alt="Open Science Research Excellence" title="Open Science Research Excellence" /> </a> <button class="d-block d-lg-none navbar-toggler ml-auto" type="button" data-toggle="collapse" data-target="#navbarMenu" aria-controls="navbarMenu" aria-expanded="false" aria-label="Toggle navigation"> <span class="navbar-toggler-icon"></span> </button> <div class="w-100"> <div class="d-none d-lg-flex flex-row-reverse"> <form method="get" action="https://waset.org/search" class="form-inline my-2 my-lg-0"> <input class="form-control mr-sm-2" type="search" placeholder="Search Conferences" value="M. 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Sasajima"> <input type="submit" class="btn_search" value="Search"> </div> </div> </form> </div> </div> <div class="row mt-3"> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Commenced</strong> in January 2007</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Frequency:</strong> Monthly</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Edition:</strong> International</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Paper Count:</strong> 10</div> </div> </div> </div> <h1 class="mt-3 mb-3 text-center" style="font-size:1.6rem;">Search results for: M. Sasajima</h1> <div class="card publication-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">10</span> Acoustic Finite Element Analysis of a Slit Model with Consideration of Air Viscosity</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/search?q=M.%20Sasajima">M. Sasajima</a>, <a href="https://publications.waset.org/search?q=M.%20Watanabe"> M. Watanabe</a>, <a href="https://publications.waset.org/search?q=T.%20Yamaguchi%20Y.%20Kurosawa"> T. Yamaguchi Y. Kurosawa</a>, <a href="https://publications.waset.org/search?q=Y.%20Koike"> Y. Koike</a> </p> <p class="card-text"><strong>Abstract:</strong></p> <p>In very narrow pathways, the speed of sound propagation and the phase of sound waves change due to the air viscosity. We have developed a new finite element method (FEM) that includes the effects of air viscosity for modeling a narrow sound pathway. This method is developed as an extension of the existing FEM for porous sound-absorbing materials. The numerical calculation results for several three-dimensional slit models using the proposed FEM are validated against existing calculation methods.</p> <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/search?q=Simulation" title="Simulation">Simulation</a>, <a href="https://publications.waset.org/search?q=FEM" title=" FEM"> FEM</a>, <a href="https://publications.waset.org/search?q=air%20viscosity" title=" air viscosity"> air viscosity</a>, <a href="https://publications.waset.org/search?q=slit." title=" slit."> slit.</a> </p> <a href="https://publications.waset.org/9996581/acoustic-finite-element-analysis-of-a-slit-model-with-consideration-of-air-viscosity" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/9996581/apa" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">APA</a> <a href="https://publications.waset.org/9996581/bibtex" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">BibTeX</a> <a href="https://publications.waset.org/9996581/chicago" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Chicago</a> <a href="https://publications.waset.org/9996581/endnote" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">EndNote</a> <a href="https://publications.waset.org/9996581/harvard" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Harvard</a> <a href="https://publications.waset.org/9996581/json" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">JSON</a> <a href="https://publications.waset.org/9996581/mla" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">MLA</a> <a href="https://publications.waset.org/9996581/ris" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">RIS</a> <a href="https://publications.waset.org/9996581/xml" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">XML</a> <a href="https://publications.waset.org/9996581/iso690" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">ISO 690</a> <a href="https://publications.waset.org/9996581.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">1631</span> </span> </div> </div> <div class="card publication-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">9</span> FEM Analysis of Occluded Ear Simulator with Narrow Slit Pathway</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/search?q=M.%20Sasajima">M. Sasajima</a>, <a href="https://publications.waset.org/search?q=T.%20Yamaguchi"> T. Yamaguchi</a>, <a href="https://publications.waset.org/search?q=M.%20Watanabe"> M. Watanabe</a>, <a href="https://publications.waset.org/search?q=Y.%20Koike"> Y. Koike</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper discusses the propagation of sound waves in air, specifically in narrow rectangular pathways of an occluded-ear simulator for acoustic measurements. In narrow pathways, both the speed of sound and the phase of the sound waves are affected by the damping of the air viscosity. Herein, we propose a new finite-element method (FEM) that considers the effects of the air viscosity. The method was developed as an extension of existing FEMs for porous, sound-absorbing materials. The results of a numerical calculation for a three-dimensional ear-simulator model using the proposed FEM were validated by comparing with theoretical lumped-parameter modeling analysis and standard values. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/search?q=Ear%20simulator" title="Ear simulator">Ear simulator</a>, <a href="https://publications.waset.org/search?q=FEM" title=" FEM"> FEM</a>, <a href="https://publications.waset.org/search?q=simulation" title=" simulation"> simulation</a>, <a href="https://publications.waset.org/search?q=viscosity." title=" viscosity."> viscosity.</a> </p> <a href="https://publications.waset.org/10002240/fem-analysis-of-occluded-ear-simulator-with-narrow-slit-pathway" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/10002240/apa" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">APA</a> <a href="https://publications.waset.org/10002240/bibtex" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">BibTeX</a> <a href="https://publications.waset.org/10002240/chicago" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Chicago</a> <a href="https://publications.waset.org/10002240/endnote" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">EndNote</a> <a href="https://publications.waset.org/10002240/harvard" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Harvard</a> <a href="https://publications.waset.org/10002240/json" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">JSON</a> <a href="https://publications.waset.org/10002240/mla" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">MLA</a> <a href="https://publications.waset.org/10002240/ris" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">RIS</a> <a href="https://publications.waset.org/10002240/xml" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">XML</a> <a href="https://publications.waset.org/10002240/iso690" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">ISO 690</a> <a href="https://publications.waset.org/10002240.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">2098</span> </span> </div> </div> <div class="card publication-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">8</span> Acoustic Analysis with Consideration of Damping Effects of Air Viscosity in Sound Pathway</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/search?q=M.%20Sasajima">M. Sasajima</a>, <a href="https://publications.waset.org/search?q=M.%20Watanabe"> M. Watanabe</a>, <a href="https://publications.waset.org/search?q=T.%20Yamaguchi"> T. Yamaguchi</a>, <a href="https://publications.waset.org/search?q=Y.%20Kurosawa"> Y. Kurosawa</a>, <a href="https://publications.waset.org/search?q=Y.%20Koike"> Y. Koike</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Sound pathways in the enclosures of small earphones are very narrow. In such narrow pathways, the speed of sound propagation and the phase of sound waves change because of the air viscosity. We have developed a new finite element method that includes the effects of damping due to air viscosity for modeling the sound pathway. This method is developed as an extension of the existing finite element method for porous sound-absorbing materials. The numerical calculation results using the proposed finite element method are validated against the existing calculation methods. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/search?q=Simulation" title="Simulation">Simulation</a>, <a href="https://publications.waset.org/search?q=FEM" title=" FEM"> FEM</a>, <a href="https://publications.waset.org/search?q=air%20viscosity" title=" air viscosity"> air viscosity</a>, <a href="https://publications.waset.org/search?q=damping." title=" damping."> damping.</a> </p> <a href="https://publications.waset.org/8614/acoustic-analysis-with-consideration-of-damping-effects-of-air-viscosity-in-sound-pathway" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/8614/apa" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">APA</a> <a href="https://publications.waset.org/8614/bibtex" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">BibTeX</a> <a href="https://publications.waset.org/8614/chicago" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Chicago</a> <a href="https://publications.waset.org/8614/endnote" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">EndNote</a> <a href="https://publications.waset.org/8614/harvard" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Harvard</a> <a href="https://publications.waset.org/8614/json" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">JSON</a> <a href="https://publications.waset.org/8614/mla" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">MLA</a> <a href="https://publications.waset.org/8614/ris" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">RIS</a> <a href="https://publications.waset.org/8614/xml" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">XML</a> <a href="https://publications.waset.org/8614/iso690" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">ISO 690</a> <a href="https://publications.waset.org/8614.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">2197</span> </span> </div> </div> <div class="card publication-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">7</span> Finite Element Method Analysis of Occluded-Ear Simulator and Natural Human Ear Canal</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/search?q=M.%20Sasajima">M. Sasajima</a>, <a href="https://publications.waset.org/search?q=T.%20Yamaguchi"> T. Yamaguchi</a>, <a href="https://publications.waset.org/search?q=Y.%20Hu"> Y. Hu</a>, <a href="https://publications.waset.org/search?q=Y.%20Koike"> Y. Koike</a> </p> <p class="card-text"><strong>Abstract:</strong></p> <p>In this paper, we discuss the propagation of sound in the narrow pathways of an occluded-ear simulator typically used for the measurement of insert-type earphones. The simulator has a standardized frequency response conforming to the international standard (IEC60318-4). In narrow pathways, the speed and phase of sound waves are modified by viscous air damping. In our previous paper, we proposed a new finite element method (FEM) to consider the effects of air viscosity in this type of audio equipment. In this study, we will compare the results from the ear simulator FEM model, and those from a three dimensional human ear canal FEM model made from computed tomography images, with the measured frequency response data from the ear canals of 18 people.</p> <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/search?q=Ear%20simulator" title="Ear simulator">Ear simulator</a>, <a href="https://publications.waset.org/search?q=FEM" title=" FEM"> FEM</a>, <a href="https://publications.waset.org/search?q=viscosity" title=" viscosity"> viscosity</a>, <a href="https://publications.waset.org/search?q=human%20ear%20canal." title=" human ear canal."> human ear canal.</a> </p> <a href="https://publications.waset.org/10005587/finite-element-method-analysis-of-occluded-ear-simulator-and-natural-human-ear-canal" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/10005587/apa" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">APA</a> <a href="https://publications.waset.org/10005587/bibtex" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">BibTeX</a> <a href="https://publications.waset.org/10005587/chicago" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Chicago</a> <a href="https://publications.waset.org/10005587/endnote" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">EndNote</a> <a href="https://publications.waset.org/10005587/harvard" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Harvard</a> <a href="https://publications.waset.org/10005587/json" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">JSON</a> <a href="https://publications.waset.org/10005587/mla" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">MLA</a> <a href="https://publications.waset.org/10005587/ris" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">RIS</a> <a href="https://publications.waset.org/10005587/xml" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">XML</a> <a href="https://publications.waset.org/10005587/iso690" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">ISO 690</a> <a href="https://publications.waset.org/10005587.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">1128</span> </span> </div> </div> <div class="card publication-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">6</span> Excitation Experiments of a Cone Loudspeaker and Vibration-Acoustic Analysis Using FEM</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/search?q=Y.%20Hu">Y. Hu</a>, <a href="https://publications.waset.org/search?q=X.%20Zhao"> X. Zhao</a>, <a href="https://publications.waset.org/search?q=T.%20Yamaguchi"> T. Yamaguchi</a>, <a href="https://publications.waset.org/search?q=M.%20Sasajima"> M. Sasajima</a>, <a href="https://publications.waset.org/search?q=Y.%20Koike"> Y. Koike</a> </p> <p class="card-text"><strong>Abstract:</strong></p> To focus on the vibration mode of a cone loudspeaker, which acts as an electroacoustic transducer, excitation experiments were performed using two types of loudspeaker units: one employing an impulse hammer and the other a sweep signal. The on-axis sound pressure frequency properties of the loudspeaker were evaluated, and the characteristic properties of the loudspeakers were successfully determined in both excitation experiments. Moreover, under conditions identical to the experiment conditions, a coupled analysis of the vibration-acoustics of the cone loudspeaker was performed using an acoustic analysis software program that considers the impact of damping caused by air viscosity. The result of sound pressure frequency properties with the numerical analysis are the most closely match that measured in the excitation experiments over a wide range of frequency bands. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/search?q=Anechoic%20room" title="Anechoic room">Anechoic room</a>, <a href="https://publications.waset.org/search?q=finite%20element%20method" title=" finite element method"> finite element method</a>, <a href="https://publications.waset.org/search?q=impulse%0D%0Ahammer" title=" impulse hammer"> impulse hammer</a>, <a href="https://publications.waset.org/search?q=loudspeaker" title=" loudspeaker"> loudspeaker</a>, <a href="https://publications.waset.org/search?q=reverberation%20room" title=" reverberation room"> reverberation room</a>, <a href="https://publications.waset.org/search?q=sweep%20signal." title=" sweep signal."> sweep signal.</a> </p> <a href="https://publications.waset.org/10003536/excitation-experiments-of-a-cone-loudspeaker-and-vibration-acoustic-analysis-using-fem" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/10003536/apa" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">APA</a> <a href="https://publications.waset.org/10003536/bibtex" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">BibTeX</a> <a href="https://publications.waset.org/10003536/chicago" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Chicago</a> <a href="https://publications.waset.org/10003536/endnote" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">EndNote</a> <a href="https://publications.waset.org/10003536/harvard" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Harvard</a> <a href="https://publications.waset.org/10003536/json" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">JSON</a> <a href="https://publications.waset.org/10003536/mla" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">MLA</a> <a href="https://publications.waset.org/10003536/ris" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">RIS</a> <a href="https://publications.waset.org/10003536/xml" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">XML</a> <a href="https://publications.waset.org/10003536/iso690" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">ISO 690</a> <a href="https://publications.waset.org/10003536.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">1798</span> </span> </div> </div> <div class="card publication-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">5</span> Optimization of Loudspeaker Part Design Parameters by Air Viscosity Damping Effect</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/search?q=Yue%20Hu">Yue Hu</a>, <a href="https://publications.waset.org/search?q=Xilu%20Zhao"> Xilu Zhao</a>, <a href="https://publications.waset.org/search?q=Takao%20Yamaguchi"> Takao Yamaguchi</a>, <a href="https://publications.waset.org/search?q=Manabu%20Sasajima"> Manabu Sasajima</a>, <a href="https://publications.waset.org/search?q=Yoshio%20Koike"> Yoshio Koike</a>, <a href="https://publications.waset.org/search?q=Akira%20Hara"> Akira Hara</a> </p> <p class="card-text"><strong>Abstract:</strong></p> <p>This study optimized the design parameters of a cone loudspeaker as an example of high flexibility of the product design. We developed an acoustic analysis software program that considers the impact of damping caused by air viscosity. In sound reproduction, it is difficult to optimize each parameter of the loudspeaker design. To overcome the limitation of the design problem in practice, this study presents an acoustic analysis algorithm to optimize the design parameters of the loudspeaker. The material character of cone paper and the loudspeaker edge were the design parameters, and the vibration displacement of the cone paper was the objective function. The results of the analysis showed that the design had high accuracy as compared to the predicted value. These results suggested that although the parameter design is difficult, with experience and intuition, the design can be performed easily using the optimized design found with the acoustic analysis software.</p> <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/search?q=Air%20viscosity" title="Air viscosity">Air viscosity</a>, <a href="https://publications.waset.org/search?q=design%20parameters" title=" design parameters"> design parameters</a>, <a href="https://publications.waset.org/search?q=loudspeaker" title=" loudspeaker"> loudspeaker</a>, <a href="https://publications.waset.org/search?q=optimization." title=" optimization. "> optimization. </a> </p> <a href="https://publications.waset.org/10005860/optimization-of-loudspeaker-part-design-parameters-by-air-viscosity-damping-effect" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/10005860/apa" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">APA</a> <a href="https://publications.waset.org/10005860/bibtex" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">BibTeX</a> <a href="https://publications.waset.org/10005860/chicago" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Chicago</a> <a href="https://publications.waset.org/10005860/endnote" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">EndNote</a> <a href="https://publications.waset.org/10005860/harvard" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Harvard</a> <a href="https://publications.waset.org/10005860/json" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">JSON</a> <a href="https://publications.waset.org/10005860/mla" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">MLA</a> <a href="https://publications.waset.org/10005860/ris" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">RIS</a> <a href="https://publications.waset.org/10005860/xml" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">XML</a> <a href="https://publications.waset.org/10005860/iso690" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">ISO 690</a> <a href="https://publications.waset.org/10005860.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">1194</span> </span> </div> </div> <div class="card publication-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">4</span> Chaotic Oscillations of Diaphragm Supported by Nonlinear Springs with Hysteresis</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/search?q=M.%20Sasajima">M. Sasajima</a>, <a href="https://publications.waset.org/search?q=T.%20Yamaguchi"> T. Yamaguchi</a>, <a href="https://publications.waset.org/search?q=Y.%20Koike"> Y. Koike</a>, <a href="https://publications.waset.org/search?q=A.%20Hara"> A. Hara</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper describes vibration analysis using the finite element method for a small earphone, especially for the diaphragm shape with a low-rigidity. The viscoelastic diaphragm is supported by multiple nonlinear concentrated springs with linear hysteresis damping. The restoring forces of the nonlinear springs have cubic nonlinearity. The finite elements for the nonlinear springs with hysteresis are expressed and are connected to the diaphragm that is modeled by linear solid finite elements in consideration of a complex modulus of elasticity. Further, the discretized equations in physical coordinates are transformed into the nonlinear ordinary coupled equations using normal coordinates corresponding to the linear natural modes. We computed the nonlinear stationary and non-stationary responses due to the internal resonance between modes with large amplitude in the nonlinear springs and elastic modes in the diaphragm. The non-stationary motions are confirmed as the chaos due to the maximum Lyapunov exponents with a positive number. From the time histories of the deformation distribution in the chaotic vibration, we identified nonlinear modal couplings. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/search?q=Nonlinear%20Vibration" title="Nonlinear Vibration">Nonlinear Vibration</a>, <a href="https://publications.waset.org/search?q=Finite%20Element%20Method" title=" Finite Element Method"> Finite Element Method</a>, <a href="https://publications.waset.org/search?q=Chaos" title="Chaos ">Chaos </a>, <a href="https://publications.waset.org/search?q=Small%20Earphone." title="Small Earphone.">Small Earphone.</a> </p> <a href="https://publications.waset.org/1556/chaotic-oscillations-of-diaphragm-supported-by-nonlinear-springs-with-hysteresis" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/1556/apa" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">APA</a> <a href="https://publications.waset.org/1556/bibtex" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">BibTeX</a> <a href="https://publications.waset.org/1556/chicago" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Chicago</a> <a href="https://publications.waset.org/1556/endnote" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">EndNote</a> <a href="https://publications.waset.org/1556/harvard" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Harvard</a> <a href="https://publications.waset.org/1556/json" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">JSON</a> <a href="https://publications.waset.org/1556/mla" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">MLA</a> <a href="https://publications.waset.org/1556/ris" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">RIS</a> <a href="https://publications.waset.org/1556/xml" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">XML</a> <a href="https://publications.waset.org/1556/iso690" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">ISO 690</a> <a href="https://publications.waset.org/1556.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">1783</span> </span> </div> </div> <div class="card publication-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">3</span> Nonlinear Impact Responses for a Damped Frame Supported by Nonlinear Springs with Hysteresis Using Fast FEA</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/search?q=T.%20Yamaguchi">T. Yamaguchi</a>, <a href="https://publications.waset.org/search?q=M.%20Watanabe"> M. Watanabe</a>, <a href="https://publications.waset.org/search?q=M.%20Sasajima"> M. Sasajima</a>, <a href="https://publications.waset.org/search?q=C.%20Yuan"> C. Yuan</a>, <a href="https://publications.waset.org/search?q=S.%20Maruyama"> S. Maruyama</a>, <a href="https://publications.waset.org/search?q=T.%20B.%20Ibrahim"> T. B. Ibrahim</a>, <a href="https://publications.waset.org/search?q=H.%20Tomita"> H. Tomita</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper deals with nonlinear vibration analysis using finite element method for frame structures consisting of elastic and viscoelastic damping layers supported by multiple nonlinear concentrated springs with hysteresis damping. The frame is supported by four nonlinear concentrated springs near the four corners. The restoring forces of the springs have cubic non-linearity and linear component of the nonlinear springs has complex quantity to represent linear hysteresis damping. The damping layer of the frame structures has complex modulus of elasticity. Further, the discretized equations in physical coordinate are transformed into the nonlinear ordinary coupled differential equations using normal coordinate corresponding to linear natural modes. Comparing shares of strain energy of the elastic frame, the damping layer and the springs, we evaluate the influences of the damping couplings on the linear and nonlinear impact responses. We also investigate influences of damping changed by stiffness of the elastic frame on the nonlinear coupling in the damped impact responses. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/search?q=Dynamic%20response" title="Dynamic response">Dynamic response</a>, <a href="https://publications.waset.org/search?q=Nonlinear%20impact%20response" title=" Nonlinear impact response"> Nonlinear impact response</a>, <a href="https://publications.waset.org/search?q=Finite%0D%0AElement%20analysis" title=" Finite Element analysis"> Finite Element analysis</a>, <a href="https://publications.waset.org/search?q=Numerical%20analysis." title=" Numerical analysis."> Numerical analysis.</a> </p> <a href="https://publications.waset.org/10002251/nonlinear-impact-responses-for-a-damped-frame-supported-by-nonlinear-springs-with-hysteresis-using-fast-fea" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/10002251/apa" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">APA</a> <a href="https://publications.waset.org/10002251/bibtex" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">BibTeX</a> <a href="https://publications.waset.org/10002251/chicago" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Chicago</a> <a href="https://publications.waset.org/10002251/endnote" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">EndNote</a> <a href="https://publications.waset.org/10002251/harvard" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Harvard</a> <a href="https://publications.waset.org/10002251/json" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">JSON</a> <a href="https://publications.waset.org/10002251/mla" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">MLA</a> <a href="https://publications.waset.org/10002251/ris" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">RIS</a> <a href="https://publications.waset.org/10002251/xml" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">XML</a> <a href="https://publications.waset.org/10002251/iso690" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">ISO 690</a> <a href="https://publications.waset.org/10002251.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">1720</span> </span> </div> </div> <div class="card publication-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2</span> Theoretical Analysis of Damping Due to Air Viscosity in Narrow Acoustic Tubes</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/search?q=M.%20Watanabe">M. Watanabe</a>, <a href="https://publications.waset.org/search?q=T.%20Yamaguchi"> T. Yamaguchi</a>, <a href="https://publications.waset.org/search?q=M.%20Sasajima"> M. Sasajima</a>, <a href="https://publications.waset.org/search?q=Y.%20Kurosawa"> Y. Kurosawa</a>, <a href="https://publications.waset.org/search?q=Y.%20Koike"> Y. Koike</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Headphones and earphones have many extremely small holes or narrow slits; they use sound-absorbing or porous material (i.e., dampers) to suppress vibratory system resonance. The air viscosity in these acoustic paths greatly affects the acoustic properties. Simulation analyses such as the finite element method (FEM) therefore require knowledge of the material properties of sound-absorbing or porous materials, such as the characteristic impedance and propagation constant. The transfer function method using acoustic tubes is a widely known measuring method, but there is no literature on taking measurements up to the audible range. To measure the acoustic properties at high-range frequencies, the acoustic tubes that form the measuring device need to be narrowed, and the distance between the two microphones needs to be reduced. However, when the tubes are narrowed, the characteristic impedance drops below the air impedance. In this study, we considered the effect of air viscosity in an acoustical tube, introduced a theoretical formula for this effect in the form of complex density and complex sonic velocity, and verified the theoretical formula. We also conducted an experiment and observed the effect from air viscosity in the actual measurements. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/search?q=acoustic%20tube" title="acoustic tube">acoustic tube</a>, <a href="https://publications.waset.org/search?q=air%20viscosity" title=" air viscosity"> air viscosity</a>, <a href="https://publications.waset.org/search?q=earphones" title=" earphones"> earphones</a>, <a href="https://publications.waset.org/search?q=FEM" title=" FEM"> FEM</a>, <a href="https://publications.waset.org/search?q=porous%20material" title=" porous material"> porous material</a>, <a href="https://publications.waset.org/search?q=sound-absorbing%20material" title=" sound-absorbing material"> sound-absorbing material</a>, <a href="https://publications.waset.org/search?q=transfer%20function%20method" title=" transfer function method"> transfer function method</a> </p> <a href="https://publications.waset.org/15236/theoretical-analysis-of-damping-due-to-air-viscosity-in-narrow-acoustic-tubes" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/15236/apa" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">APA</a> <a href="https://publications.waset.org/15236/bibtex" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">BibTeX</a> <a href="https://publications.waset.org/15236/chicago" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Chicago</a> <a href="https://publications.waset.org/15236/endnote" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">EndNote</a> <a href="https://publications.waset.org/15236/harvard" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Harvard</a> <a href="https://publications.waset.org/15236/json" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">JSON</a> <a href="https://publications.waset.org/15236/mla" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">MLA</a> <a href="https://publications.waset.org/15236/ris" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">RIS</a> <a href="https://publications.waset.org/15236/xml" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">XML</a> <a href="https://publications.waset.org/15236/iso690" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">ISO 690</a> <a href="https://publications.waset.org/15236.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">2051</span> </span> </div> </div> <div class="card publication-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">1</span> Examination of the Effect of Air Viscosity on Narrow Acoustic Tubes Using FEM Involving Complex Effective Density and Complex Bulk Modulus</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/search?q=M.%20Watanabe">M. Watanabe</a>, <a href="https://publications.waset.org/search?q=T.%20Yamaguchi"> T. Yamaguchi</a>, <a href="https://publications.waset.org/search?q=M.%20Sasajima"> M. Sasajima</a>, <a href="https://publications.waset.org/search?q=Y.%20Kurosawa"> Y. Kurosawa</a>, <a href="https://publications.waset.org/search?q=Y.%20Koike"> Y. Koike</a> </p> <p class="card-text"><strong>Abstract:</strong></p> <p>Earphones and headphones, which are compact electro-acoustic transducers, tend to have a lot of acoustic absorption materials and porous materials known as dampers, which often have a large number of extremely small holes and narrow slits to inhibit the resonance of the vibrating system, because the air viscosity significantly affects the acoustic characteristics in such acoustic paths. In order to perform simulations using the finite element method (FEM), it is necessary to be aware of material characteristics such as the impedance and propagation constants of sound absorbing materials and porous materials. The transfer function is widely known as a measurement method for an acoustic tube with such physical properties, but literature describing the measurements at the upper limits of the audible range is yet to be found. The acoustic tube, which is a measurement instrument, must be made narrow, and the distance between the two sets of microphones must be shortened in order to take measurements of acoustic characteristics at higher frequencies. When such a tube is made narrow, however, the characteristic impedance has been observed to become lower than the impedance of air. This paper considers the cause of this phenomenon to be the effect of the air viscosity and describes an FEM analysis of an acoustic tube considering air viscosity to compare to the theoretical formula by including the effect of air viscosity in the theoretical formula for an acoustic tube.</p> <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/search?q=Acoustic%20tube" title="Acoustic tube">Acoustic tube</a>, <a href="https://publications.waset.org/search?q=air%20viscosity" title=" air viscosity"> air viscosity</a>, <a href="https://publications.waset.org/search?q=earphones" title=" earphones"> earphones</a>, <a href="https://publications.waset.org/search?q=FEM" title=" FEM"> FEM</a>, <a href="https://publications.waset.org/search?q=porous%20materials" title=" porous materials"> porous materials</a>, <a href="https://publications.waset.org/search?q=sound%20absorbing%20materials" title=" sound absorbing materials"> sound absorbing materials</a>, <a href="https://publications.waset.org/search?q=transfer%20function%20method." title=" transfer function method."> transfer function method.</a> </p> <a href="https://publications.waset.org/9996570/examination-of-the-effect-of-air-viscosity-on-narrow-acoustic-tubes-using-fem-involving-complex-effective-density-and-complex-bulk-modulus" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/9996570/apa" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">APA</a> <a href="https://publications.waset.org/9996570/bibtex" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">BibTeX</a> <a href="https://publications.waset.org/9996570/chicago" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">Chicago</a> <a href="https://publications.waset.org/9996570/endnote" target="_blank" rel="nofollow" class="btn btn-primary btn-sm">EndNote</a> <a href="https://publications.waset.org/9996570/harvard" target="_blank" rel="nofollow" class="btn 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