Computer modeling of low pressure laboratory experiments on Indiana limestone and Sierra white granite and the implications for yield estimation.

摘要

Some effects of material model uncertainties on yield estimation have been explored. Data on spherical shocks at low pressure (below 100 kb) in small limestone samples have been used to adjust the model parameters of computer simulations run at LLNL. The low pressure regime is important for future verification treaties involving nuclear yield determinations below 10 kilotons (kt) because the current treaty and likely future treaties prohibit the detectors from being close to the explosive canister. Past computer studies have emphasized modeling parameters at higher pressures appropriate for treaties concerned with high yields (150 kt) and they revealed that porosity and water content are the main concerns. This investigation confirms that porosity and water content continue to play a major role at low yields, but now strength becomes very important. This study also provided insight into the dynamic behavior of rapidly loaded porous limestone in three different configurations: dry, saturated at room temperature plus saturated and frozen. Specifically, wet porous limestone showed a surprisingly strong failure curve for waves with a peak pressure below 10 kb.