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Acoustics, Dynamics, and Controls

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Full-Text Articles in Mechanical Engineering

Extracting Vibration Characteristics Of A Guitar Using Finite Element, Modal Analysis, And Digital Image Correlation Techniques, Kiran Patil, Javad Baqersad, Daniel Ludwigsen, Yaomin Dong Apr 2018

Extracting Vibration Characteristics Of A Guitar Using Finite Element, Modal Analysis, And Digital Image Correlation Techniques, Kiran Patil, Javad Baqersad, Daniel Ludwigsen, Yaomin Dong

Daniel Ludwigsen

The sound quality generated by the guitar depends on the vibration characteristics (i.e. natural frequencies and mode shapes) of this instrument. Thus, it is of particular interest to the guitar manufacturers to be able to obtain global information about the characteristics of the guitar. Traditional sensors can only measure at discrete locations. However, digital image correlation (DIC) can measure full-field data on the surface of the structure. In the current paper, a finite element (FE) model of a guitar with free boundary configurations was developed using quadratic solid elements. An eigensolution was performed on the FE model to determine ...


High-Resolution Performance Analysis Of A Large Building With Linear Dispersion Ductwork System, Anthony Fontanini, Alberto Passalacqua, Umesh Vaidya, Michael Olsen, Baskar Ganapathysubramanian Feb 2018

High-Resolution Performance Analysis Of A Large Building With Linear Dispersion Ductwork System, Anthony Fontanini, Alberto Passalacqua, Umesh Vaidya, Michael Olsen, Baskar Ganapathysubramanian

Umesh Vaidya

Buildings consume 40% of the U.S. annual energy usage. The energy usage of building can drastically be reduced by proper management of the thermal load in large interior spaces. A well designed space should include systems that balance both occupant comfort and efficiency. Recently linear dispersion ductwork systems have been shown to be a promising solution for creating both comfortable and efficient spaces. We investigate long-term thermal behavior of a 10,000 ft2 building that utilizes a linear air dispersion system. We optimize the operating point of the HVAC system by utilizing three dimensional Computational Fluid Dynamic (CFD) simulations ...


Ultrasound Scatter In Heterogeneous 3d Microstructures, Brady Engle, Ronald A. Roberts, Robert Grandin Jun 2017

Ultrasound Scatter In Heterogeneous 3d Microstructures, Brady Engle, Ronald A. Roberts, Robert Grandin

Robert Grandin

This paper reports on a computational study of ultrasound propagation in heterogeneous metal microstructures. Random spatial fluctuations in elastic properties over a range of length scales relative to ultrasound wavelength can give rise to scatter-induced attenuation, backscatter noise, and phase front aberration. It is of interest to quantify the dependence of these phenomena on the microstructure parameters, for the purpose of quantifying deleterious consequences on flaw detectability, and for the purpose of material characterization. Valuable tools for estimation of microstructure parameters (e.g. grain size) through analysis of ultrasound backscatter have been developed based on approximate weak-scattering models. While useful ...


Modeling For Ut Inspection Of Anisotropic Materials, Robert A. Roberts, Robert Grandin, Andrew Downs Jun 2017

Modeling For Ut Inspection Of Anisotropic Materials, Robert A. Roberts, Robert Grandin, Andrew Downs

Robert Grandin

This presentation reports on the extension of an established CNDE ultrasound beam transmission model to accommodate transmission in generally anisotropic materials. Using principles of elastodynamic reciprocity, the model expresses the internal wave field as a surface integral over the radiating transducer, employing the full Green function (point force response function) for the combined body under inspection and the coupling medium. The model evaluates the Green function asymptotically for short wavelength, and is therefore referred to as an asymptotic Green function model (AGF). The integrand of the transducer integral is projected on to a discretely orthogonal Gaussian basis, leading to a ...


Surrogate Modeling Of Ultrasonic Testing Simulations Using Variable-Fidelity Models And Data-Driven Methods, Robert Grandin, Leifur Leifsson Jun 2017

Surrogate Modeling Of Ultrasonic Testing Simulations Using Variable-Fidelity Models And Data-Driven Methods, Robert Grandin, Leifur Leifsson

Robert Grandin

Ultrasonic testing (UT) is used to detect internal flaws in materials or to characterize material properties [1]. Computational simulations are an important part of the UT process. Having fast surrogate models for ultrasonic testing (UT) simulations is key for inverse analysis and model-assisted probability of detection (MAPOD) in the field of nondestructive evaluation. In fact, it is impractical to perform the aforementioned tasks in a timely manner using current simulation models directly. Fast surrogate models can make these processes computationally tractable. This paper presents investigations of using surrogate modeling techniques to create fast approximate models of UT simulator responses. In ...


Validation Of Utsim2, A New Ultrasonic Simulation Package, Robert Grandin, Timothy Gray Jun 2017

Validation Of Utsim2, A New Ultrasonic Simulation Package, Robert Grandin, Timothy Gray

Robert Grandin

The Center for NDE (CNDE) at Iowa State University has a long history of developing physics models for NDE and packaging these models into simulation tools which make the modeling capabilities accessible to CNDE’s industrial sponsors. Recent work at CNDE has led to the development of a new ultrasonic simulation package, UTSim2, which aims to continue this tradition of supporting industrial application of CNDE models. In order to meet this goal, UTSim2 has been designed as an extensible software package which can support previously-developed physics models as well as future models yet to be developed. Initial work has focused ...


Incorporation Of Composite Defects From Ultrasonic Nde Into Cad And Fe Models, Onur Rauf Bingol, Bryan Schiefelbein, Robert J. Grandin, Stephen D. Holland, Adarsh Krishnamurthy Jun 2017

Incorporation Of Composite Defects From Ultrasonic Nde Into Cad And Fe Models, Onur Rauf Bingol, Bryan Schiefelbein, Robert J. Grandin, Stephen D. Holland, Adarsh Krishnamurthy

Robert Grandin

Fiber-reinforced composites are widely used in aerospace industry due to their combined properties of high strength and low weight. However, owing to their complex structure, it is difficult to assess the impact of manufacturing defects and service damage on their residual life. While, ultrasonic NDE is the preferred method to identify the presence of defects (such as delaminations) in composites, there are no reasonable ways to model the damage and evaluate the structural integrity of composites. Hence, a framework to incorporate flaws and known damage models automatically into a finite element analysis (FEA) of composites will aid in accessing their ...


Vector Acoustic Intensity Around A Tuning Fork, Daniel A. Russell, Justin Junell, Daniel O. Ludwigsen May 2017

Vector Acoustic Intensity Around A Tuning Fork, Daniel A. Russell, Justin Junell, Daniel O. Ludwigsen

Daniel Ludwigsen

The acoustic intensity vector field around a tuning fork is investigated. Theory for a longitudinal quadrupole source predicts a well-defined transition between near-field and far-field, with significant circulation of sound energy in the near-field. Vector components of the time-averaged intensity were measured using a two-microphone intensity probe and found to agree well with predictions from theory. The vector intensity map is interpreted, and shown to provide useful information about the near-field of an acoustic source.


Better Understanding Of Resonance Through Modeling And Visualization, Daniel O. Ludwigsen, Cayla Jewett, Matthew Jusczcyk May 2017

Better Understanding Of Resonance Through Modeling And Visualization, Daniel O. Ludwigsen, Cayla Jewett, Matthew Jusczcyk

Daniel Ludwigsen

Students encounter cavity resonance and waveguide phenomena in acoustics courses and texts, where the study is usually limited to cases with simple geometries: parallelepipeds, cylinders, and spheres. Long-wavelength approximations help with situations of more complexity, as in the classic Helmholtz resonator. At Kettering University, we are beginning to employ finite element modeling in our acoustics classes to help undergraduates better understand the acoustic modes of actual structures. This approach to the time-independent wave equation (the Helmholtz equation) was first used in a research and measurements class to investigate two classic resonance problems. The first problem was a study of resonance ...


Acoustic Testing And Modeling: An Advanced Undergraduate Laboratory, Daniel A. Russell, Daniel O. Ludwigsen May 2017

Acoustic Testing And Modeling: An Advanced Undergraduate Laboratory, Daniel A. Russell, Daniel O. Ludwigsen

Daniel Ludwigsen

This paper describes an advanced laboratory course in acoustics, specifically targeted for students with an interest in engineering applications at a school with a strongly integrated industrial co-op program. The laboratory course is developed around a three-pronged approach to problem solving that combines and integrates theoretical models, computational models, and experimental data. The course is structured around modules that begin with fundamental concepts and build laboratory skills and expand the knowledge base toward a final project. Students keep a detailed laboratory notebook, write research papers in teams, and must pass laboratory certification exams. This paper describes the course layout and ...


Constraints On Acoustic Signaling Among Birds Breeding In Secondary Cavities: The Effects Of Weather, Cavity Material, And Noise On Sound Propagation, John P. Swaddle, Caitlin R. Kight, Saji Perera, Eduardo Davila-Reyes, Shena Sikora Feb 2017

Constraints On Acoustic Signaling Among Birds Breeding In Secondary Cavities: The Effects Of Weather, Cavity Material, And Noise On Sound Propagation, John P. Swaddle, Caitlin R. Kight, Saji Perera, Eduardo Davila-Reyes, Shena Sikora

John Swaddle

Increasing evidence suggests that anthropogenic noise from urbanization affects animal acoustic communication. We investigated whether the begging calls of nestling Eastern Bluebirds (Sialia sialis) varied along a disturbance gradient of ambient noise. Contrary to our prediction and the results of a previous study of nestling Tree Swallows (Tachycineta bicolor), we found that nestling Eastern Bluebirds did not increase the amplitude or structural characteristics—including frequency, rate, and duration—of their vocalizations in response to ambient noise. However, we found that prevalent temperature and humidity conditions attenuated begging calls. Specifically, in warmer, more humid weather, vocalizations of nestling Eastern Bluebirds attenuated ...


Quantifying And Mapping Induced Strain In Canvas Paintings Using Laser Shearography, Philip Klausmeyer, Matthew Cushman, Ivo Dobrev, Morteza Khaleghi, Ellery Harrington, Xiaoran Chen, Cosme Furlong Nov 2016

Quantifying And Mapping Induced Strain In Canvas Paintings Using Laser Shearography, Philip Klausmeyer, Matthew Cushman, Ivo Dobrev, Morteza Khaleghi, Ellery Harrington, Xiaoran Chen, Cosme Furlong

Morteza Khaleghi

Evaluation of museums’ condition standards used for the exhibition of canvas paintings requires a quantitative technique capable of measuring strain induced by changes in temperature, relative humidity, and the thermomechanical effects of light, as well as the effects of ambient vibration. This paper presents advances in developing a customized shearography system for temporal characterization of strains that occur on canvas paintings when subjected to changes in exhibition conditions. The shearography system performs measurements of displacement derivatives along two orthogonal shearing directions and is synchronized with an IR camera to provide thermal maps of the area analyzed. Innovations incorporated into the ...


Multi-Disciplinary Hands-On Desktop Learning Modules And Modern Pedagogies, Bernard J. Van Wie, David B. Thiessen, Marc Compere, Ximena Toro, Jennifer C. Adam, Et Al. Sep 2016

Multi-Disciplinary Hands-On Desktop Learning Modules And Modern Pedagogies, Bernard J. Van Wie, David B. Thiessen, Marc Compere, Ximena Toro, Jennifer C. Adam, Et Al.

Marc Compere

Our team’s research focuses on fundamental problems in undergraduate education in terms of how to expand use of well researched, yet still “new”, teaching pedagogies of ‘sensing’ or ‘hands-on’, ‘active’ and ‘problem-based learning’ within engineering courses. It is now widely accepted that traditional lectures ARE NOT best for students – yet that is what the community almost universally does. To address this issue we are developing new Desktop Learning Modules (DLMs) that contain miniaturized processes with a uniquely expandable electronic system to contend with known sensor systems/removable cartridges, as well as, unknown expansions to the project. We have shown ...


Project Haiti 2012: Providing An Experiential Learning Experience Through The Design And Delivery Of A Water Purifier In Haiti, Yung Wong, Johnathon Camp, Shavin Pinto, Kyle Fennesy, Marc Compere, Yan Tang Sep 2016

Project Haiti 2012: Providing An Experiential Learning Experience Through The Design And Delivery Of A Water Purifier In Haiti, Yung Wong, Johnathon Camp, Shavin Pinto, Kyle Fennesy, Marc Compere, Yan Tang

Marc Compere

In this paper, we share our experiences and lessons learned from Project Haiti 2012, a project to design and install a water purification system serving 20,000 people per day in the largest tent city in Haiti. Project Haiti 2012 was the third and largest system we have built for Haitians and represents a huge success for all participants and stakeholders. This paper discusses the unique experiential learning opportunity involved in the design and delivery of the water purifier in a foreign developing country. Multiple positive educational, social, and economic outcomes were achieved including students applying knowledge gained from coursework ...


High Tech High Touch: Lessons Learned From Project Haiti 2011, Yan Tang, Marc Compere, Yung Lun Wong, Jared Anthony Coleman, Matthew Charles Selkirk Sep 2016

High Tech High Touch: Lessons Learned From Project Haiti 2011, Yan Tang, Marc Compere, Yung Lun Wong, Jared Anthony Coleman, Matthew Charles Selkirk

Marc Compere

In this paper, we will share our experiences and lessons learned from a design project for providing clean water to a Haitian orphanage (Project Haiti 2011). Supported by funds from a renewable energy company and the university president’s office, five engineering students and two faculty members from Embry-Riddle Aeronautical University successfully designed and installed a solar powered water purification system for an orphanage located in Chambellan, Haiti. This paper discusses the unique educational experiences gained from unusual design constraints, such as ambiguity of existing facilities due to limited communication, logistics of international construction at a remote village location, and ...


Effects Of Noise, Reverberation And Foreign Accent On Native And Non-Native Listeners’ Performance Of English Speech Comprehension, Zhao Ellen Peng, Lily M. Wang May 2016

Effects Of Noise, Reverberation And Foreign Accent On Native And Non-Native Listeners’ Performance Of English Speech Comprehension, Zhao Ellen Peng, Lily M. Wang

Lily M Wang

A large number of non-native English speakers may be found in American classrooms, both as listeners and talkers. Little is known about how this population comprehends speech in realistic adverse acoustical conditions. A study was conducted to investigate the effects of background noise level (BNL), reverberation time (RT), and talker foreign accent on native and non-native listeners' speech comprehension, while controlling for English language abilities. A total of 115 adult listeners completed comprehension tasks under 15 acoustic conditions: three BNLs (RC-30, RC-40, and RC-50) and five RTs (from 0.4 to 1.2 s). Fifty-six listeners were tested with speech ...


Assessment Of Noise-Induced Annoyance By Tones In Noise From Building Mechanical Systems, Joonhee Lee, Lily M. Wang Apr 2016

Assessment Of Noise-Induced Annoyance By Tones In Noise From Building Mechanical Systems, Joonhee Lee, Lily M. Wang

Lily M Wang

Prominent tones in noise generated by mechanical equipment in buildings can cause complaints from occupants in buildings. The ISO 1996-2 and ANSI S1.13 standards describe methodologies and metrics to quantify tonality perception, but the influence of tones in noise on human annoyance and performance is not fully understood yet. This paper investigates annoyance responses of humans while exposed to background noise with tonal components. Twenty participants completed digit span tasks while exposed to noise signals with differing levels of tones and overall loudness. Subjects were also asked to rate their annoyance after completing tasks under each noise signal. The ...


The Impact Of Building Acoustics On Speech Comprehension And Student Achievement, Lily M. Wang Apr 2016

The Impact Of Building Acoustics On Speech Comprehension And Student Achievement, Lily M. Wang

Lily M Wang

The movement for improved classroom acoustics has primarily been grounded on studies that show how building acoustics (i.e. background noise levels and room reverberation) affect speech intelligibility, as determined by speech recognition tests. What about actual student learning, though? If students do not understand each spoken word in the classroom perfectly, can they still manage to achieve high scholastic success? This presentation will review two recent studies conducted at the University of Nebraska – Lincoln, linking classroom acoustic conditions to student learning outcomes and speech comprehension (rather than simply recognition). In the first, acoustic measurements in two public school districts ...


Determining Annoyance Thresholds Of Tones In Noise, Jennifer M. Francis, Joonhee Lee, Lily M. Wang Apr 2016

Determining Annoyance Thresholds Of Tones In Noise, Jennifer M. Francis, Joonhee Lee, Lily M. Wang

Lily M Wang

Building services equipment often produces noise signatures with significant tones in them that can lead to complaints in the built environment. Previous studies have investigated prominence levels of assorted tonal frequencies, but it is still unclear what prominence of the tones across varying tonal frequencies can lead to human annoyance. This project seeks to apply two different methods towards defining annoyance thresholds of tones in noise at two tonal frequencies: 125 Hz and 500 Hz. In the first, subjects are asked to perform a task, while exposed to ten minutes of a broadband noise spectrum with a specific level of ...


The Impact Of Building Acoustics On Speech Comprehension And Student Achievement, Lily M. Wang Apr 2016

The Impact Of Building Acoustics On Speech Comprehension And Student Achievement, Lily M. Wang

Lily M Wang

The movement for improved classroom acoustics has primarily been grounded on studies that show how building acoustics (i.e. background noise levels and room reverberation) affect speech intelligibility, as determined by speech recognition tests. What about actual student learning, though? If students do not understand each spoken word in the classroom perfectly, can they still manage to achieve high scholastic success? This presentation will review two recent studies conducted at the University of Nebraska – Lincoln, linking classroom acoustic conditions to student learning outcomes and speech comprehension (rather than simply recognition). In the first, acoustic measurements in two public school districts ...


Effects Of Room Acoustics On Comprehension Of Foreign-Accented Speech By Native And Non-Native English-Speaking Listeners, Zhao Peng, Kristin E. Hanna, Brenna N. Boyd, Lily M. Wang Apr 2016

Effects Of Room Acoustics On Comprehension Of Foreign-Accented Speech By Native And Non-Native English-Speaking Listeners, Zhao Peng, Kristin E. Hanna, Brenna N. Boyd, Lily M. Wang

Lily M Wang

In a previous study by the authors, reverberation time (RT) and background noise level (BNL) were both found to have negative effects on native and non-native English-speaking listeners in comprehending English speech produced by native American-English-speaking talkers. Comprehension scores were adjusted for listeners’ baseline English proficiency levels. In the present study, instead of native English-speaking talkers, two native Mandarin Chinese talkers (one male, one female) with similar English spoken proficiency were recruited to produce the same speech materials used in the previous study. A similar methodology was adopted to conduct speech comprehension tests on three groups of listeners: 1) native ...


Quantification And Subjective Perception Of Varying Reflection Densities In Measured Room Impulsed Responses, Hyun Hong, Lily M. Wang Apr 2016

Quantification And Subjective Perception Of Varying Reflection Densities In Measured Room Impulsed Responses, Hyun Hong, Lily M. Wang

Lily M Wang

This project focuses on quantifying and testing the subjective perception of reflection densities, or the number of reflections per second, from different room impulse responses. The widely used room acoustic metric, reverberation time, is linked to the perceived reverberation in a room. Two different rooms having the same reverberation time, though, can have different reflection densities in their room impulse responses, and this difference in reflection density may affect how listeners perceive spatial impression in rooms. To investigate how sensitive humans are to a change of reflection density, this paper first reviews assorted parameters for quantifying reflection density from measured ...


Room Acoustic Effects On Speech Comprehension Of English-As-Second-Language Talkers And Listeners Versus Native-English-Speaking Talkers And Listeners, Lily M. Wang Apr 2016

Room Acoustic Effects On Speech Comprehension Of English-As-Second-Language Talkers And Listeners Versus Native-English-Speaking Talkers And Listeners, Lily M. Wang

Lily M Wang

Approximately 21% of the children in the United States school system speak a language other than English at home, but are being taught in English at school. English is additionally being used more and more often as a common language in international settings, even though participants at these international events again are not native English speakers. How do adverse room acoustic environments, including higher background noise levels and longer reverberation times, impact English-as-a-Second-Language (ESL) talkers and listeners versus native English-speaking talkers and listeners? This presentation focuses on two recent studies at the University of Nebraska that investigate how assorted room ...


Umass Amherst Green Building Guidelines 2013, Ludmilla Pavlova-Gillham, Ted Mendoza, Ezra Small, Patricia O'Flaherty, Nariman Mostafavi, Mohamed Farzinmoghadam, Somayeh Tabatabaee Pozveh Oct 2015

Umass Amherst Green Building Guidelines 2013, Ludmilla Pavlova-Gillham, Ted Mendoza, Ezra Small, Patricia O'Flaherty, Nariman Mostafavi, Mohamed Farzinmoghadam, Somayeh Tabatabaee Pozveh

Ludmilla D Pavlova

Facilities & Campus Services, Sustainable UMass and Campus Planning support sustainability and energy conservation initiatives by providing in-house resources to campus staff as well as designers and contractors working with the University. The UMass Amherst Green Building Guidelines provide a framework for approaching new construction and major renovation projects at UMass Amherst that are undergoing LEED certification by focusing the conversation on green building aspects that are most important to the campus. They are intended to be the beginning of a dynamic conversation between designers, environmental consultants and constructors, university stakeholders, and users of new high performance buildings.


A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel Oct 2015

A High-Speed X-Ray Detector System For Noninvasive Fluid Flow Measurements, Timothy B. Morgan, Benjamin R. Halls, Terrence R. Meyer, Theodore J. Heindel

Terrence R Meyer

The opaque nature of many multiphase flows has long posed a significant challenge to the visualization and measurement of desired characteristics. To overcome this difficulty, X-ray imaging, both in the form of radiography and computed tomography, has been used successfully to quantify various multiphase flow phenomena. However, the relatively low temporal resolution of typical X-ray systems limit their use to moderately slow flows and time-average values. This paper discusses the development of an X-ray detection system capable of high-speed radiographic imaging that can be used to visualize multiphase flows. Details of the hardware will be given and then applied to ...


Analytical And Numerical Analysis Of Low Velocity Impact On Metallic Sandwich Panel With Polyurethane Foam Core, Mohsen Mahdian, Hossein Ebrahimi Aug 2015

Analytical And Numerical Analysis Of Low Velocity Impact On Metallic Sandwich Panel With Polyurethane Foam Core, Mohsen Mahdian, Hossein Ebrahimi

Hossein Ebrahimi

No abstract provided.


Study Of An Axial Fan Combined With A Microperforated Duct, Seungkyu Lee Aug 2015

Study Of An Axial Fan Combined With A Microperforated Duct, Seungkyu Lee

Seungkyu Lee

The fans used in the ventilation duct systems usually fall into two categories: (i) axial, and (ii) centrifugal. These types of fans are distinguished by having different performance characteristics. For instance, centrifugal fans are capable of generating high static pressures compare to axial fans. However, an axial fan can deal with higher air volume flow rates than a centrifugal fan, and, more importantly, an axial fan produces relatively low fan noise compared to a centrifugal fan. Thus, even though axial fans may be advantageous from a noise point-of-view, they are generally avoided in duct systems when relatively high static pressures ...


Optical Detection Of Acoustic Emission Signals, C Harvey Palmer, Robert E. Green Jr Jun 2015

Optical Detection Of Acoustic Emission Signals, C Harvey Palmer, Robert E. Green Jr

Robert A. Green

Piezoelectric transducers, long used in the generation and detection of ultrasonic waves, have more recently been the detector of choice for acoustic emission signals. Optical probing methods, however, have several important advantages for acoustic emission studies: (1) they have an inherent broad frequency response, free from mechanical resonances, (2) they do not interfere with the acoustic waves. (3) since the focused optical beam diameters are typically only a few hundredths of a millimeter, optical methods can probe very close to a crack or a twin, (4) they can probe internally in transparent media, and (5) they can be used over ...


Elastic Wave Field Computation In Multilayered Nonplanar Solid Structures: A Mesh-Free Semianalytical Approach, Sourav Banerjee, Tribikram Kundu Apr 2015

Elastic Wave Field Computation In Multilayered Nonplanar Solid Structures: A Mesh-Free Semianalytical Approach, Sourav Banerjee, Tribikram Kundu

Sourav Banerjee

Multilayered solid structures made of isotropic, transversely isotropic, or general anisotropic materials are frequently used in aerospace, mechanical, and civil structures. Ultrasonic fields developed in such structures by finite size transducers simulating actual experiments in laboratories or in the field have not been rigorously studied. Several attempts to compute the ultrasonic field inside solid media have been made based on approximate paraxial methods like the classical ray tracing and multi-Gaussian beam models. These approximate methods have several limitations. A new semianalytical method is adopted in this article to model elastic wave field in multilayered solid structures with planar or nonplanar ...


Phonon Confinement Using Spirally Designed Elastic Resonators In Discrete Continuum, Sourav Banerjee, Raiz U. Ahmed Apr 2015

Phonon Confinement Using Spirally Designed Elastic Resonators In Discrete Continuum, Sourav Banerjee, Raiz U. Ahmed

Sourav Banerjee

Periodic and chiral orientation of microstructures, here we call phononic crystals, have extraordinary capabilities to facilitate the innovative design of new generation metamaterials. Periodic arrangements of phononic crystals are capable of opening portals of non-passing, non-dispersive mechanical waves. Defying conventional design of regular periodicity, in this paper spirally periodic but chiral orientation of resonators are envisioned. Dynamics of the spirally connected resonators and the acoustic wave propagation through the spirally connected multiple local resonators are studied using fundamental physics. In present study the spiral systems with local resonators are assumed to be discrete media immersed in fluid. In this paper ...