Center Impedance Method for Estimating Complex Modulus with Wide Frequency Range and Large Loss Factors

A simple method for determining viscoelasticity over a wide frequency range using the frequency response function (FRF) mobility obtained by the center impedance method is presented. As user data comprise the FRF between the velocity of the excitation rod and excitation force, it is challenging to s...

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Autores principales:	Ryuzo Horiguchi, Yoshiro Oda, Keito Sato, Hiroto Kozuka, Takao Yamaguchi
Formato:	article
Lenguaje:	EN
Publicado:	Hindawi Limited 2021
Materias:	Physics QC1-999
Acceso en línea:	https://doaj.org/article/99ab7240ee484eaab012d4f03e2867d9
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spelling	oai:doaj.org-article:99ab7240ee484eaab012d4f03e2867d92021-11-08T02:37:03ZCenter Impedance Method for Estimating Complex Modulus with Wide Frequency Range and Large Loss Factors1875-920310.1155/2021/1644823https://doaj.org/article/99ab7240ee484eaab012d4f03e2867d92021-01-01T00:00:00Zhttp://dx.doi.org/10.1155/2021/1644823https://doaj.org/toc/1875-9203A simple method for determining viscoelasticity over a wide frequency range using the frequency response function (FRF) mobility obtained by the center impedance method is presented. As user data comprise the FRF between the velocity of the excitation rod and excitation force, it is challenging to separate the signal and noise. Our proposed method is based on the FRF obtained from the analytical solution of the equation of motion of the viscoelastic beam and relationship between the complex wavenumber (real wavenumber and attenuation constant) of flexural wave and viscoelasticity. Furthermore, a large loss factor can be handled over a wide frequency range without using the half-power bandwidth. In this study, actual FRF mobility data containing noise were processed using preprocessing, inverse calculation, and postprocessing. Preprocessing removed low-coherence data, compensates for the effects of instrument gain, and transformed the FRF into its dimensionless equivalent. Then, inverse calculations were used to solve the mobility equation and determine the complex wavenumber. In postprocessing, the complex wavenumber obtained by the inverse calculation was curve fitted using functions with mechanical significance. Consequently, the storage modulus based on the curve-fitted complex wavenumber was a monotonically increasing frequency function. The loss factor had a smooth frequency dependence such that it has the maximum value at a single frequency. The proposed method can be applied to composite materials, where the application of time-temperature superposition is challenging. We utilized the measured FRF mobility data obtained over a duration of several seconds, and this method can also be applied to materials with large loss factors of 1 or more.Ryuzo HoriguchiYoshiro OdaKeito SatoHiroto KozukaTakao YamaguchiHindawi LimitedarticlePhysicsQC1-999ENShock and Vibration, Vol 2021 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Physics QC1-999
spellingShingle	Physics QC1-999 Ryuzo Horiguchi Yoshiro Oda Keito Sato Hiroto Kozuka Takao Yamaguchi Center Impedance Method for Estimating Complex Modulus with Wide Frequency Range and Large Loss Factors
description	A simple method for determining viscoelasticity over a wide frequency range using the frequency response function (FRF) mobility obtained by the center impedance method is presented. As user data comprise the FRF between the velocity of the excitation rod and excitation force, it is challenging to separate the signal and noise. Our proposed method is based on the FRF obtained from the analytical solution of the equation of motion of the viscoelastic beam and relationship between the complex wavenumber (real wavenumber and attenuation constant) of flexural wave and viscoelasticity. Furthermore, a large loss factor can be handled over a wide frequency range without using the half-power bandwidth. In this study, actual FRF mobility data containing noise were processed using preprocessing, inverse calculation, and postprocessing. Preprocessing removed low-coherence data, compensates for the effects of instrument gain, and transformed the FRF into its dimensionless equivalent. Then, inverse calculations were used to solve the mobility equation and determine the complex wavenumber. In postprocessing, the complex wavenumber obtained by the inverse calculation was curve fitted using functions with mechanical significance. Consequently, the storage modulus based on the curve-fitted complex wavenumber was a monotonically increasing frequency function. The loss factor had a smooth frequency dependence such that it has the maximum value at a single frequency. The proposed method can be applied to composite materials, where the application of time-temperature superposition is challenging. We utilized the measured FRF mobility data obtained over a duration of several seconds, and this method can also be applied to materials with large loss factors of 1 or more.
format	article
author	Ryuzo Horiguchi Yoshiro Oda Keito Sato Hiroto Kozuka Takao Yamaguchi
author_facet	Ryuzo Horiguchi Yoshiro Oda Keito Sato Hiroto Kozuka Takao Yamaguchi
author_sort	Ryuzo Horiguchi
title	Center Impedance Method for Estimating Complex Modulus with Wide Frequency Range and Large Loss Factors
title_short	Center Impedance Method for Estimating Complex Modulus with Wide Frequency Range and Large Loss Factors
title_full	Center Impedance Method for Estimating Complex Modulus with Wide Frequency Range and Large Loss Factors
title_fullStr	Center Impedance Method for Estimating Complex Modulus with Wide Frequency Range and Large Loss Factors
title_full_unstemmed	Center Impedance Method for Estimating Complex Modulus with Wide Frequency Range and Large Loss Factors
title_sort	center impedance method for estimating complex modulus with wide frequency range and large loss factors
publisher	Hindawi Limited
publishDate	2021
url	https://doaj.org/article/99ab7240ee484eaab012d4f03e2867d9
work_keys_str_mv	AT ryuzohoriguchi centerimpedancemethodforestimatingcomplexmoduluswithwidefrequencyrangeandlargelossfactors AT yoshirooda centerimpedancemethodforestimatingcomplexmoduluswithwidefrequencyrangeandlargelossfactors AT keitosato centerimpedancemethodforestimatingcomplexmoduluswithwidefrequencyrangeandlargelossfactors AT hirotokozuka centerimpedancemethodforestimatingcomplexmoduluswithwidefrequencyrangeandlargelossfactors AT takaoyamaguchi centerimpedancemethodforestimatingcomplexmoduluswithwidefrequencyrangeandlargelossfactors
_version_	1718443024713777152

Center Impedance Method for Estimating Complex Modulus with Wide Frequency Range and Large Loss Factors

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