THEORETICAL HYPERVELOCITY IMPACT CALCULATIONS USING THE PICWICK CODE.
Interim rept., 24 June-23 Dec 63,
GENERAL ELECTRIC CO PHILADELPHIA PA MISSILE AND SPACE DIV
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The principle uncertainty in the visco-plastic model of hypervelocity impact is the lack of data on strain-rate effects under the severe conditions or interest. Estimates of strainrate coefficient for iron and aluminum are first determined that are compatible both with observed strain-rate effects in plastic waves and the very abrupt shock profiles known to exist at pressures greater than about .2 megabar. In the second part of the report detailed calculations are presented describing the cratering process for a cylindrical projectile impacting a thick target of like metal. It is shown that momentum scaling cannot be justified energy scaling for geometrically similar impact situations is accurately predicted upon taking into account the different rates of shock propagation during the early stages of the cratering process. Strength effects of the target do not vanish with increasing impact velocity. In the third part of the report the cratering and the penetration process for thin plates is studied. PICWICK calculations are presented and the results discussed in terms of the interactions of shock waves, rarefraction waves, and configuration geometry. Author