Understanding High Rate Behavior Through Low Rate Analog
Final rept. 10 Sep 2009-31 Jan 2014
OXFORD UNIV (UNITED KINGDOM) DEPT OF ENGINEERING SCIENCE
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The research explores rate dependence in polymers. Results in the literature show that rate dependence is governed by polymer transitions. PVC was used as a model material for studying strain rate-temperature interdependence using four plasticizer levels, which modify its mechanical properties and alter the position of the transitions with respect to temperature and frequency. A methodology was then developed whereby the high rate uniaxial stress-strain response of one of the PVC compositions was simulated in low rate experiments by reducing the initial temperature, and then profiling the temperature to simulate the adiabatic heating which occurs under rapid loading. The same technique was applied to other PVC and PMMA compositions, and differences in the responses were considered. A polymer bonded sugar was tested both in compression and using the Brazilian test, and high rate data were shown to be well reproduced by low rate experiments at reduced temperature temperature rises in these materials are very low. The experiments were supported by the development of new thermocouple and stress gauge arrangements. Although the research was mainly experimental, some complementary numerical modeling was also performed and reported.
- Polymer Chemistry