| 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. In addition, 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.; To successfully model the gouging phenomenon, the high strain, high strain-rate, high temperature conditions and shock wave behavior present in high velocity impact dynamics must be effectively dealt with. Constitutive laws modeling inelastic material response and an appropriate equation of state also need to be considered to model these effects.; Hydrocodes are computational solvers designed specifically to handle such non-linear, large deformation, high shock, hydrodynamic applications. Part of this dissertation evaluates the ability of the hydrocode CTH to handle the problem of determining the onset of gouging. This evaluation is based on considering the hydrocode theory and its implications on the development of the gouging phenomenon. Also considered is 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 velocities of impact was undertaken. Due to 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. |
