CONVERSION OF OSCILLATORY SHEAR DATA FROM PROPELLANTS AND EXPLOSIVES

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Authors
  1. Brousseau, P.
  2. Duncan, E.J.S.
Corporate Authors
Defence Research Establishment Valcartier, Valcartier QUE (CAN)
Abstract
The stress relaxation modulus (E(t)) is an important property of viscoelastic materials such as rocket propellants or plastic-bonded explosives. The measure of this property, through relaxation tests in uniaxial extension, can be lengthy and material-consuming. An alternative to these measurements involves the use of a dynamic spectrometer to perform a series of frequency sweeps at different temperatures, thereby reducing the total time for the tests as well as the amount of required material, and increasing the precision and the repeatability of the results. However, the latter results have to be transformed from the frequency domain to the time domain to recuperate the relaxation modulus. In this study, both stress relaxation tests and frequency/temperature sweep tests have been performed on highly loaded polymers using a dynamic spectrometer. Three different methods of transforming the results from one type of test to the other have been investigated: Fourier integral transforms, the Ninomiya-Ferry relation and discrete relaxation spectrum determinations. All three methods gave similar results for the transformation, with the relaxation spectrum method providing results over the widest range of shifted time. The overall accuracy of the predictions is variable, the average deviation between predicted and experimental stress relaxation ranging grom 5% in the best cases to 23% in the worst ones.
Keywords
Dynamic mechanical analysis;Storage modulus;Loss modulus;High loaded polymers
Report Number
DREV-TM-9625 — Technical Memorandum
Date of publication
01 Sep 1997
Number of Pages
60
DSTKIM No
98-00395
CANDIS No
507010
Format(s):
Hardcopy;Document Image stored on Optical Disk

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