Modeling a Nonlinear Melt Region as a Result of High-Speed Sliding

Abstract

The solution discussed in this paper relates to the high-speed movement of a vehicle along a rigid support in which friction becomes a heat energy source for melt. A one-dimensional nonlinear heat transfer set of equations dependent upon a vertical forcing function, created by horizontal movement characterized by velocity, is considered in the supersonic regime. A good example of this type of condition occurs within the U.S. Air Force Holloman High Speed Test Track at Alamogordo in New Mexico, which supports experiments routinely run at hypersonic speeds. In addition, there are several applications including rail guns, high-speed trains, and hypervelocity projectile research. This application is the setup at the Holloman High Speed Test Track. The testing there involves articles propelled at high velocities, in excess of Mach 8, while attached to a rail by way of wraparound slippers. Modeling the entire test run would be computationally expensive due to thermal–mechanical coupling and nonlinearities in geometry as well as material. This work uses a finite difference scheme to solve the one-dimensional heat transfer equation while accounting for the time the slipper is in contact with the rail, versus not in contact, as well as the differing pressures experienced by the slipper as it travels down the track. It also accounts for material properties that change with respect to temperature, leading to nonlinearities. The model output shows a direct correlation between predicted melt at the surface and the damage as measured by a slipper after the acceleration portion of a test event.