Characterization of the Dynamic Behavior of Porous Solids. Part 6. Dynamic Response of Porous Ceramics-Experiments.
Final rept. 14 Jan 74-31 Jan 76,
SRI INTERNATIONAL MENLO PARK CA
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High pressure dynamic stress wave experiments were performed on sintered alumina of several initial porosities and the multiple Lagrangian gage technique was used to record stress and particle velocity histories at several locations within the specimen in order to calculate the constitutive loading and unloading paths. We now have a family of such paths shown in Figure 10 that can be used to construct an equation-of-state surface for a predictive hydrodynamic computer code. The results show that sintered alumina with initial porosites ranging from 20 to 45 exhibit no significant time-dependence in their constitutive relations when shocked to peak pressure of hundreds of kbar where the precursor is overdriven. When shocked to pressures slightly above the Hugoniot elastic limit, however, a time-dependent response does exist see Figures A-9 and A-10. Further experiments would be needed to give us an accurate predictive capability in this region. We performed a few experiments on flame-sprayed alumina and flame-sprayed hafnium titanate, which yield constitutive paths in the region below 7 kbar. Author
- Ceramics, Refractories and Glass
- Miscellaneous Materials