ONE-DIMENSIONAL INTERACTION OF A CYLINDRICAL UNLOADING WAVE WITH A MOVING ELASTIC PLASTIC BOUNDARY

The one-dimensional dynamic problem of the theory of large elastic-plastic deformations is considered for the interaction of an unloading wave with an elastic-plastic boundary. It is shown that before the occurrence of the unloading wave, the increasing pressure gradient leads to quasistatic deformation of the elastic-viscoplastic material filling the round tube, which is retained in the tube due to friction on its wall, resulting in the formation of near-wall viscoplastic flow and an elastic core. The unloading wave is initiated at the moment of the onset of slippage of the material along the inner wall of the tube. Calculations were conducted using the ray method of constructing approximate solutions behind strong discontinuity surfaces, and ray expansions of the solutions behind the cylindrical surfaces of discontinuities were obtained.