WSEAS Transactions on Applied and Theoretical Mechanics
Print ISSN: 1991-8747, E-ISSN: 2224-3429
Volume 14, 2019
Increasing Accuracy of Discrete-Time Computation of Linear Rheological and Viscoelastic Material Functions
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Abstract: The paper is addressed to increasing the accuracy of discrete-time computation of linear rheological and viscoelastic material functions belonging to the class of smooth non-bandlimited (NBL) signals. It is demonstrated that the ideology of classical discrete-time processing, which is based on preserving accurate spectrum over the Nyquist frequency band, ignores the anti-aliasing distortion caused by removal of a signal portion above the Nyquist frequency needed for preserving accurate spectrum and, so, gives the inadequate accuracy evaluation of computed material functions. To ensure the adequate accuracy evaluation of NBL material functions, we propose to waive the criterion of preserving accurate spectrum over the Nyquist frequency band, but instead to use the criterion of maintaining accurate shape of a material function in the time-domain. Both the criteria are compared and the appropriate error models are developed and investigated. Increase of accuracy of filtering algorithms is studied for computing NBL material functions. Design of discrete-time filters is proposed by the identification method with employing bandlimited input and output portions of a pair of NBL functions. The proposed design approach is validated by constructing a discrete-time differentiator with employing bandlimited portions of the Cauchy pulse and its derivative.
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Keywords: Linear Rheological and Viscoelastic Material Functions, Discrete-Time Processing, Accuracy, Non-Bandlimitedness, Filtering Algorithms
Pages: 212-221
WSEAS Transactions on Applied and Theoretical Mechanics, ISSN / E-ISSN: 1991-8747 / 2224-3429, Volume 14, 2019, Art. #24