Scaling numerical models for hypervelocity test sled slipper-rail impacts

Abstract

Hypervelocity test sled slipper-rail impacts have been simulated numerically using the finite volume hydrocode, ChartD to the Three-Halves (CTH). This study addresses the difficulties of applying CTH model solutions to real test sled runs. Past CTH models using dimensions different than actual test sleds have been used to study phenomenological aspects of the problem. However, quantitative results from the CTH model solution do not apply directly to actual test sled runs due to strain rate effects and time scale differences. The Buckingham Pi Theorem is applied to two potential hypervelocity gouging models. Validity of the invariant products is tested using sample CTH hypervelocity gouging models that are scaled up to simulate dimensions of a real test sled. Real test sled dimensions are desired in order to more closely simulate actual test sled runs. Invariant products developed from application of the Buckingham Pi Theorem can be used as guidelines for determining whether a CTH model is applicable to a test sled with specific dimensions. Strain rate effects are investigated to study whether deviations between scaled CTH models may be reduced by modifying the constitutive model.