The influence of wave dispersion characteristics on the determination of mechanical relaxation spectra
作者:
P. R. Williams,
D. J. A. Williams,
期刊:
Journal of Rheology
(AIP Available online 1994)
卷期:
Volume 38,
issue 4
页码: 1211-1226
ISSN:0148-6055
年代: 1994
DOI:10.1122/1.550591
出版商: The Society of Rheology
关键词: VISCOELASTICITY;STRESS RELAXATION;SHEAR WAVES;GROUP VELOCITY;PHASE VELOCITY;WAVE PROPAGATION;SPECTROSCOPY
数据来源: AIP
摘要:
A new rheometrical technique has been developed to determine the mechanical relaxation spectra of viscoelastic materials by measurement of shear wave group and phase velocities in a virtual gap rheometer. The technique’s sensitivity and accuracy in providing relaxation spectra directly from measurements arises from exploitation of marked changes in wave dispersion characteristics in the vicinity of stress relaxation mechanisms. The new technique is compared with two conventional, wave‐based rheometrical techniques (based on pulse‐propagation and resonance measurements), which are adversely affected by wave dispersion. The superior accuracy and sensitivity of the new technique over conventional rheometry is demonstrated with reference to the Maxwell model and published relaxation spectra. Experimental results obtained on a concentrated colloidal dispersion serve to demonstrate the measurement principles.
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