Analysis of Computational Methods for the Treatment of Material Interfaces

摘要

Rocket sled tests at the Air Force Research Laboratory's Holloman High Speed Test Track frequently approach velocities where gouging development becomes the limiting factor to achieving higher operating velocities. Direct observation of the gouging process is not possible so computational modeling is necessary to study the phenomenon. Since gouging development is dependent on the impact surface conditions, the method used to model material interfaces directly affects the accuracy of the solution. Three methods are available in the hydrocode CTH to handle material interfaces: (1) materials are joined at the interface, (2) a frictionless slide line is inserted, and (3) a boundary layer interface is established. An axisymmetric impact scenario is used to explore these methods and their influence on high energy impact solutions. The three methods are also compared in an axisymmetric sliding scenario. The method of joining materials at the contact surface appears well suited to the simulation of high energy impact events. The frictionless slide line method produces significant numerical instability, while the boundary layer interface method is too limited for two dimensional applications.