Refinement of a Hypervelocity Gouging Model for the Rocket Sled Test

Abstract

In an effort to improve the accuracy of current numerical models of the hypervelocity gouging impact phenomenon at the Holloman Air Force Base High Speed Test Track (HHSTT), several investigations were conducted. First, a metallurgical study of a gouged rail section is summarized that quantifies the nature of the non-equilibrium thermodynamic event. Second, the current CTH model of the sled/rail interaction is scaled mathematically to determine the feasibility of a laboratory experiment to generate gouging. Additionally, the various material contact schemes in CTH are evaluated to determine the most accurate approach in the gouging impact problem. Next, the absence of specific constitutive models for 1080 steel and VascoMax 300 (which are the materials of interest in the HHSTT gouging problem) is addressed with Split Hopkinson Bar characterization. These models are validated by comparison to Taylor Impact Tests conducted on the same materials. Finally, the two coatings used at the HHSTT to mitigate gouging are experimentally compared using the Taylor test. Conclusions are drawn from the experimentation and numerical modeling efforts with regard to the gouging phenomenon.