Physical Basis of Methods for Measuring Viscoelastic Properties
V. M. Kulik1, A. V. Boiko2,3
1Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia 2Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia 3Tyumen' State University, Tyumen', 625003, Russia
Keywords: модули упругости и сдвига, коэффициент потерь, коэффициент Пуассона, формфактор, скорость распространения колебаний, измерения на живых тканях, elasticity and shear moduli, loss coefficient, Poisson's ratio, shape factor, velocity of propagation of oscillations, measurements on living tissues
Abstract
The main methods used to measure viscoelastic properties of materials in a wide range of frequencies from 10-4 to 106 Hz are reviewed. It is demonstrated that the accuracy of many experimental methods can be increased by taking into account the shape factors, which depend on the specimen type. An example of the shape factor for a cylindrical specimen is provided, which was determined numerically on the basis of a two-dimensional deformation model taking into account the specimen geometry and Poisson's ratio. The importance of the precise determination of Poisson's ratio for rubber-like and complex-structured materials is demonstrated. Requirements to such measurements and a setup satisfying these requirements are described. Two methods for measuring viscoelastic properties of living tissues (compliance and disturbance propagation velocity) are considered. Based on the developed method of measuring these parameters for materials with a fixed thickness, methods for standartization of measurements of viscoelastic characteristics of living tissues are proposed.
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