Two-dimensional Lagrangian method for elastic-plastic flow Original Research Article

The present study uses Schulzʹs two-dimensional radiation hydrodynamic code as a framework. Three new features are added to the basic code. First, finite difference equations for deviatoric stresses and strains, shear modulus and yield strengths are written, i.e. compatibly with Schulzʹs special formulations. Material properties (i.e. shear modulus and yield strength) are dependent on pressure, compression and equivalent plastic strain (i.e. Steinberg-Guinan model). Second, modifications to the artificial viscosity are made so that the acceleration from the artificial viscosity will project onto the unit vector in the direction of local acceleration. This projection eliminates ‘false heating’ and helps maintain a stable computational grid. Also a very sharp shock front location will be obtained through this new method. Third, a semi-Eulerian method that allows the material flow through the Lagrangian mesh is used for treating the Lagrangian sliding interfaces.