An improved contact algorithm for multi-material Arbitrary Lagranian-Eulerian hydrocodes in three-dimensions

Multi-material Eulerian formulations in computational structural mechanics are traditionally approached using mixed-element thermodynamic or constitutive models. These traditional approaches replace contacting materials in an element with an approximated single material. However, this approximation often has little basis in the actual physics taking place at the contacting boundary and can easily lead to unphysical behavior due to bonding that takes place along the interface boundary. This work presents a significant departure from traditional Eulerian treatment of contact by adding a separate velocity field and solving the conservation equations separately for each material and then imposing inequality constraints associated with contact to the solutions with the appropriate traction integrals included. This results in natural treatment of contacting surfaces in an Eulerian framework and eliminates the need for mixture theory. The advantages of this method will be demonstrated with several computational examples.