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Transient Dynamics of Continuous Systems with Impact and Friction, with Applications to Musical InstrumentsVyasarayani, Chandrika Prakash 18 September 2009 (has links)
The objective of this work is to develop mathematical simulation models for predicting the transient behaviour of strings and beams subjected to impacts. The developed models are applied to study the dynamics of the piano and the sitar.
For simulating rigid point impacts on continuous systems, a new method is proposed based on the unit impulse response. The developed method allows one to relate modal velocities before and after impact, without requiring the integration of the system equations of motion during impact. The proposed method has been used to model the impact of a pinned-pinned beam with a rigid obstacle. Numerical simulations are presented to illustrate the inability of the collocation-based coefficient of restitution method to predict an accurate and energy-consistent response. The results using the unit-impulse-based coefficient of restitution method are also compared to those obtained with a penalty approach,with good agreement.
A new moving boundary formulation is presented to simulate wrapping contacts in continuous systems impacting rigid distributed obstacles. The free vibration response of an ideal string impacting a distributed parabolic obstacle located at its boundary is analyzed to understand and simulate a sitar string.
The portion of the string in contact with the obstacle is governed by a different partial differential equation (PDE) from the free portion represented by the classical string equation. These two PDEs and corresponding boundary conditions, along with the transversality condition that governs the dynamics of the moving boundary, are obtained using Hamilton's principle. A Galerkin approximation is used to convert them into a system of
nonlinear ordinary differential equations, with time-dependent mode-shapes as basis
functions. The advantages and disadvantages of the proposed method are discussed in comparison
to the penalty approach for simulating wrapping contacts. Finally, the model is used to investigate the mechanism behind the generation of the buzzing tone in a sitar. An alternate formulation using the penalty approach is also proposed, and the results are contrasted with those obtained using the moving boundary approach.
A model for studying the interaction between a flexible beam and a string at a point including friction has also been developed. This model is used to study the interaction between a piano hammer and the string. A realistic model of the piano hammer-string interaction must treat both the action mechanism and the string. An elastic stiff string model is integrated with a dynamic model of a compliant piano action mechanism with a flexible hammer shank. Simulations have been used to compare the mechanism response for
impact on an elastic string and a rigid stop.
Hammer head scuffing along the string, as well as length of time
in contact, were found to increase where an elastic string was used,
while hammer shank vibration amplitude and peak contact force decreased.
Introducing hammer-string friction decreases the duration of contact and reduces the
extent of scuffing.
Finally, significant differences in hammer and string motion were predicted for
a highly flexible hammer shank.
Initial contact time and location, length of contact period, peak contact force, hammer
vibration amplitude, scuffing extent, and string spectral content were all influenced.
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Le violon enchanté dans les contes littéraires québécois du XIXe siècle /McCallum, Amy. January 2006 (has links)
This Master's thesis is centered on the enchanted violin and its role in six literary tales from nineteenth century Quebec. The motif is traced throughout its history and its developments in various Indo-European contexts. The importance of the enchanted violin in the oral traditions of Europe and French-Canada is underlined. The motif's literary transformation in the nineteenth century is also analyzed; authors of the tales studied were chiefly concerned with the creation of a national literature, and this affected their portrayal of the enchanted violin in several ways. Vladimir Propp's structuralist morphology is used in order to define the function of the violin as a magic object in each of the works. Lastly, a mytho-critical reading of the six tales concentrates on the symbolic power of the instrument and speculates as to its ethnographic origins.
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Digital musical instruments : a design approach based on moving mechanical systemsSinyor, Elliot. January 2006 (has links)
This thesis describes the design and use of two novel digital musical instruments (DMIs) based on moving mechanical systems. The motivation behind using mechanical devices was threefold: to explore the effect of physical effort on DMIs, to make use of the device's inherent haptic and visual feedback, and to serve as a starting point for sound mappings. It was hoped that their mechanical nature would give the instruments a character that could emerge through each of the mappings. The first DMI built was the Gyrotyre, a hand-held DMI based around a small bicycle wheel outfitted with sensors that measure its speed of rotation and as well as its angle of orientation. The second DMI built was the Springwave, which consists of a loose metal spring stretched to one meter and fixed at both ends to a metal frame. The frame is in turn mounted horizontally on a hi-hat stand so that it can be raised and lowered with the pedal, thus inducing oscillation in the spring. Various mappings were designed to reflect and make use of the physical nature of both instruments. It was found that the nature of interaction with each instrument was very different depending on the mapping used. The use of mechanical devices was found to be a useful starting point for the development of mappings, and made playing the instruments engaging for the performer by the relationship between DMIs and musical contexts, a framework for characterizing DMIs that takes musical context into account is presented.
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Mrdangam mind the tani āvartanam in Karnatak music /Nelson, David Paul. January 1991 (has links)
Thesis (Ph. D.)--Wesleyan University, Middletown, Connecticut, 1991. / "A dissertation in music submitted in Partial Fulfillment of the Requirements for the Doctor of Philosophy ..." Includes bibliographical references (v. 1: p. 390-391).
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Development of the Chinese two-stringed bowed lute 'erhu' following the New Culture Movement (c. 1915-1985)Liu, Terence Michael. January 1988 (has links)
Thesis (Ph.D.)--Kent State University, 1988. / Director: Terry Miller. Includes bibliographical references.
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Issô-ryû nohkan (Noh flute) : tradition and continuity in the music of Noh drama /Anno, Mariko, January 2008 (has links)
Thesis (D.M.A.)--University of Illinois at Urbana-Champaign, 2008. / Source: Dissertation Abstracts International, Volume: 69-05, Section: A, page: 1587. Adviser: David G. Goodman. Includes supplementary digital materials. Includes bibliographical references (leaves 287-300) Available on microfilm from Pro Quest Information and Learning.
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Peasant music ensembles in Poland : a culture history /Noll, William Henry. January 1986 (has links)
Thesis (Ph. D.)--University of Washington, 1986. / Vita. Bibliography: leaves [706]-729.
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'I've got a feeling' : the effect of haptic information on the preferred location of purchase of guitars and stringed wooden instrumentsPirie, Elliot January 2017 (has links)
This thesis develops technology adoption and sensory information literatures through an evaluation of antecedents to consumers’ purchase location intention of Musical Instruments (MI). With the unique factor of instrument heterogeneity MI e-retail sales are information asymmetric propositions, where the consumer may make a sub-optimal purchase online having foregone the opportunity to experience the haptic information required to ascertain the instrument’s true quality. Despite a reticent adoption of MI e-retail from the traditional retail industry online MI sales are increasing, resulting in off-line marketplace contraction, thus investigation of consumers’ online MI purchase motivations is of value to the industry. The exploration of this topic uses a pragmatic, two-stage mixed-methods process incorporating inductive in-depth interviews with MI retail industry personnel, followed by deductive MI consumer based quantitative questionnaires. The reluctance to adopt e-retail is based on ‘expertise-led aversion’ and ‘expertise gap’ where key MI retail influencers attempt to enforce their own views on the correct way to purchase an instrument, rather than responding to consumer trends. This aversion was influenced by their own reliance on haptic information, coupled with knowledge of instrument heterogeneity and their level of musicianship. Consumer research conclusions identify that high haptic-need consumers, who tend to have greater ability and involvement, are more likely to purchase in-store whilst those with lower haptic needs are more willing to purchase MI online. Through the design and empirical testing of the Musical Instrument Need-for-Touch (MINFT) model numerous factors were identified as moderators to this basic supposition. The subsequent development of a MI consumer typology identified five distinct groups that respond to differing stimuli in relation to MI purchase location intention. These findings add to the academic discourse and enable MI retailers to enhance their offerings both in-store and online, leading to more effective targeting of their key customers.
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Identificação experimental modal da caixa acústica de um violão clássicoLöw, Alexandre Marks January 2012 (has links)
Este trabalho consiste na aplicação de técnicas de identificação de parâmetros estruturais, especificamente massa, rigidez e amortecimento, à caixa acústica de um violão clássico. A abordagem experimental tradicional é adotada, com medição de aceleração em um ponto da estrutura e excitação proveniente de martelo instrumentado registrada em diferentes pontos. As funções de resposta em frequência são então traçadas para, em conjunto com um modelo analítico representativo dos primeiros graus de liberdade do acoplamento ar/estrutura, realizar-se o ajuste de curvas e posterior identificação dinâmica. Para tanto, esta última etapa foi tratada como um problema matemático de otimização não linear no qual se busca a minimização de uma função objetivo que contabiliza de alguma forma a diferença entre o resultado das medições e os valores previstos pelo modelo utilizado. Várias funções de erro (objetivo) e vários algoritmos foram utilizados, como mínimos quadrados não linear, simplex de Nealder-Mead, algoritmo genético padrão e enxame de partículas (particle swarm), entre outros, sendo este último o de melhor desempenho entre todos, quando aplicado em conjunto com a norma da diferença dos logaritmos das magnitudes ao quadrado. Assim, uma calibração com boa concordância entre dados experimentais e resultados teóricos foi estabelecida para o modelo proposto, sendo realizada também a verificação do ajuste através da comparação de um conjunto independente de dados, trazendo, desta forma, confiabilidade para posteriores cálculos das grandezas associadas ao comportamento dinâmico utilizando-se o modelo ajustado. / This work aims at identify structural parameters of a classical acoustic guitar’s resonant chamber by comparing theoretical and experimental frequency response functions. The quantities used to construct the mass, stiffness and damping matrices of an air/structure analytical model, which is representative of the first few modes of the body, are considered as project variables, and an impact vibration testing approach is used to obtain the measured data, with a roving instrumented hammer and an accelerometer attached to a predefined point of the body. Then, a curve-fit analysis is performed as a mathematical problem of non-linear optimization, wherein the objective function, which is to be minimized, somehow accounts for the difference between the measured data and the theoretically predicted values. Some different error (objective) functions and optimization algorithms, like non-linear least-squares, Nealder-Mead simplex, standard genetic algorithm and particle swarm, among others, were applied, and the latter yielded, together with the squared error norm, the best performance. Then, an updated model was achieved with fair agreement between analytical predictions and experimental results, verified using a validation data set, bringing reliability for further theoretical predictions.
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A física e os instrumentos musicais construindo significados em uma aula de acústicaSilva, Douglas Krüger da January 2017 (has links)
Este trabalho versa sobre desenvolver a habilidade de “reconhecer características ou propriedades de fenômenos ondulatórios ou oscilatórios, relacionando-os a seus usos em diferentes contextos” (BRASIL, 2009, p.8) de uma forma menos tradicional. O objetivo foi abordar o conteúdo de acústica utilizando instrumentos musicais (violão, guitarra, flauta, xilofone, lira...). A partir de ondas estacionárias em tubos sonoros e cordas vibrantes, foram elucidados os conceitos de altura, intensidade e timbre, relacionando com os conceitos básicos de ondas – frequência, comprimento de onda, amplitude, velocidade de propagação das ondas em cordas de diferentes densidades lineares, entre outros. Também foram trabalhadas notas musicais e conceitos bem básicos de formação de acordes. A proposta foi aplicada com os dois nonos anos de um colégio particular bastante tradicional de Novo Hamburgo: o Colégio Marista Pio XII. Nesta fase final do Ensino Fundamental, o colégio disponibiliza aos seus alunos cinco períodos de Ciências da Natureza, distribuídos em: um de Biologia, dois de Física e dois de Química. A ideia é que fossem trabalhadas Competências e Habilidades comuns aos componentes curriculares, por meio de sequências didáticas. O trabalho foi aplicado em um total de seis encontros, cada um com duração de 50 min. Alguns desses períodos foram dedicados a aulas puramente expositivas, outros deles com aulas expositivas dialogadas, com a utilização de uma espiral de caderno, uma guitarra, um cavaquinho, instrumentos de sopro e do computador, onde interpretamos as frequências fundamentais emitidas pela vibração das cordas e do ar em tubos sonoros com o software Spectrogram1. Como referencial teórico, utilizamos a teoria sócio-interacionista de Vygotsky e alguns conceitos de alfabetização científica. A discussão e o manuseio de instrumentos musicais em pequenos grupos fizeram com que os alunos interagissem entre si e com o professor, favorecendo a construção do conhecimento e a interação de signos. A partir dessas interações aluno - instrumentos musicais, professor - aluno e aluno – aluno, o objetivo era abrir espaço para questionamentos, discussões e reflexões, de maneira que o conhecimento fosse sintetizado por todos. Como referência para o planejamento de ensino, construção do significado das aulas e análise das interações, utilizamos uma ferramenta analítica de Mortimer e Scott (2002). / This work is about developing the ability to "recognize characteristics or properties of wave or oscillatory phenomena, relating them to their uses in different contexts "(BRASIL, 2009, p.8), in a less traditional way. The objective was to approach the content of acoustics using musical instruments (guitar, electric guitar, flute, xylophone, lyre ...). From stationary waves in sound tubes and vibrating strings, concepts of height, intensity and timbre, were elucidated, relating them to the basic concepts of waves - frequency, wavelength, amplitude, velocity of wave propagation in strings of different linear densities, among others. Musical notes and basic concepts of chord formation were also seen. The proposal was applied with two groups of nineth graders from a very traditional private school in Novo Hamburgo: Marista Pio XII school. In this final phase of elementary school, the school offers its students five classes of Science a week, distributed in one of Biology, two of Physics and two of Chemestry. The idea was work with common skills to these curricular components, through didactic sequences. The work was applied out in a total of six classes, each lasting 50 min. Some of these were devoted to purely expository presentation, others with dialogic lectures, with the use of the spiral of a notebook, a guitar, another small kind of guitar, wind instruments and a computer where we interpret the fundamental frequencies emitted by the vibration of the strings and air in sound tubes with the Spectrogram software2. As a theoretical reference, we use Vygotsky's socio-interactionist theory and some concepts of scientific literacy. The discussion and manipulation of musical instruments in small groups led the students to interact with each other and with the teacher, favoring the construction of knowledge and interaction. From these student - musical instruments, teacher - student and student – student interactions, the objective is to open space for questions, discussions and reflections, so that knowledge was synthesized by all. As a reference for teaching planning, construction of meaning and interaction analysis, l we used an analytical tool by Mortimer and Scott (2002).
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