Date of Award

3-1-2002

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Aeronautics and Astronautics

First Advisor

Anthony N. Palazotto, PhD

Abstract

The slipper/rail interface of a hypervelocity rocket sled is subject to immense forces due to dynamic loads and impact of the slipper with the rail, and tremendous heating due to aerodynamic and frictional effects is produced at the interface. Under these severe loading conditions, the material in the rail will sometimes experience large non-linear deformations known as gouging. Hydrocodes are computational solvers designed to handle such non-linear, large deformation, high shock, hydrodynamic applications. The ability of the hydrocode CTH to handle gouge modeling is considered, as well as the manner in which temperature environments affect deformation and plastic strain. The solution techniques and material modeling are described. Using this numerical analysis tool, a study of how gouging occurs and tracing of its development at various impact velocities was undertaken, with emphasis on the effect of shock wave distribution. Modeling the intense aerodynamic and frictional heating near the contact region, the effects of temperature on gouge initiation were evaluated through the application of several thermal environment scenarios that have been developed. The effects of friction, slipper geometry, slipper velocity, and impact method have been considered. Finally, the differences between three-dimensional and two-dimensional analysis considering gouging have been evaluated.

AFIT Designator

AFIT-DS-ENY-02-01

DTIC Accession Number

ADA398636

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