Complex modes of vibration due to small-scale damping in a guitar top-plate

Modal analysis is one of the preeminent methods used by scientists and engineers to study vibrating structures. The frequency response functions obtained through this method, are, in general, complex-valued. There is, however, no agreed-upon interpretation given to the real and imaginary parts of th...

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Detalles Bibliográficos
Autores: J. A. Torres, P. L. Rendón, R. R. Boullosa
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2010
País:México
Institución:Universidad Nacional Autónoma de México
Repositorio:Redalyc-UNAM
OAI Identifier:oai:redalyc.org:47412950010
Acceso en línea:https://www.redalyc.org/articulo.oa?id=47412950010
Access Level:acceso abierto
Palabra clave:Ingeniería
guitar
mode shapes
Complex modes
damped plates
Descripción
Sumario:Modal analysis is one of the preeminent methods used by scientists and engineers to study vibrating structures. The frequency response functions obtained through this method, are, in general, complex-valued. There is, however, no agreed-upon interpretation given to the real and imaginary parts of these functions, even though it is acknowledged that their relative magnitude for different frequencies is related to the behaviour of the corresponding modes. A simple model is deduced to describe the shape of the spectrum associated with a finite-length time-signal. There is very good agreement between results obtained using this model and numerical results obtained for, in this case, the vibration of a guitar top-plate using finite element methods. One interpretation of the relative magnitudes of the real and imaginary parts of the frequency response functions is advanced. It is found that stationary-wave behaviour is associated with the dominance of the real or imaginary part; traveling-wave behaviour, on the other hand, occurs when the real and imaginary parts are of the same order of magnitude, as long as the scale of damping is large enough and resonance peaks in the spectrum are close enough.