Accession Number : AD0611751

Title :   DILATATION CONSTANTS AND COMPLEX RATIO FROM FORCED VIBRATION OF A FREE VISCOELASTIC SPHERE,

Corporate Author : COLD REGIONS RESEARCH AND ENGINEERING LAB HANOVER N H

Personal Author(s) : Lee,T. M.

Report Date : JAN 1965

Pagination or Media Count : 14

Abstract : The technique of forced vibration has been applied to the study of the properties of viscoelastic materials. It is found, through the analysis of a free sphere with a harmonic oscillating internal source, that the vibration amplitude ratio of two measuring points is associated with the complex dilatational constants and the complex ratio of the material, a quantity directly related to the complex Poisson's ratio. Therefore, from the criterion of maximum amplitude ratio (i.e. by adjusting the frequency of the source until the amplitude ratio reaches maximum), these properties can be expressed in terms of the amplitude ratios and their frequencies. For the convenience of laboratory testing, two particular amplitude ratios, in conjunction with their frequencies, have been employed for this purpose. Simple expressions are given, relating the properties of the test material to quantities measurable in the laboratory, namely the maximum amplitude ratios and their corresponding frequencies. (Author)

Descriptors :   (*VISCOELASTICITY, SPHERES), (*ELASTIC PROPERTIES, MATHEMATICAL ANALYSIS), SOLIDS, MATERIALS, VIBRATION, HARMONIC ANALYSIS, GRAPHICS, TABLES(DATA), MECHANICS

Distribution Statement : APPROVED FOR PUBLIC RELEASE