An evaluation of high velocity wear

The Holloman High Speed Test Track (HHSTT) is a rocket-powered sled track facility used for testing a variety of hypervelocity aerospace applications at speeds approaching 3000 m/s. Research conducted at the HHSTT has to consider several features that result from the physics of high velocity. The feature of gouging has been noted to be a significant factor at speeds above 1.5 km/s. This characteristic has been studied in recent years by several authors including the senior author of this paper. Another feature that is always present is that of wear between the shoe and the rail resulting from their sporadic contact as the sled travels down the rail. This paper attempts to establish a proof concept that can eventually be extended into future understanding of wear at high velocities. The authors approached wear using two separate techniques. The first technique involves the use of equations that have been successfully used to represent wear at low speeds. This technique relies on the research of Lim and Ashby and the equations they developed to model the different modes of wear. Included in this technique is the use of Archard's wear equation. The second technique, completely independent of the first, relies on the physics of frictional movement displayed by a model produced using CTH, a hydrocode developed by Sandia National Laboratory for analyzing hypervelocity impact problems. This technique considers features that are potentially present in the overall phenomenon but are limited to the use of the code. The authors have found it necessary to make simplifying assumptions in both techniques, but the end result is a better appreciation of what is needed to put together a more accurate model of wear at high velocities.