A methodology to validate 3D Arbitrary Lagrangian Eulerian codes with applications to ALEGRA

In this study we provided an experimental test bed for validating features of the Arbitrary Lagrangian Eulerian Grid for Research Applications (ALEGRA) code over a broad range of strain rates with overlapping diagnostics that encompass the multiple responses. A unique feature of the ALEGRA code is that it allows simultaneous computational treatment, within one code, of a wide range of strain-rates varying from hydrodynamic to structural conditions. This range encompasses strain rates characteristic of shock-wave propagation (10 7/s) and those characteristics of structural response (10 2/s). Most previous code validation experimental studies, however, have been restricted to simulating or investigating a single strain-rate regime. What is new and different in this investigation is that we have performed well-controlled and well-instrumented experiments, which capture features relevant to both hydrodynamic and structural response in a single experiment. Aluminum was chosen for use in this study because it is a well-characterized material. The current experiments span strain rate regimes of over 10 7/s to less than 10 2/s in a single experiment. The input conditions were extremely well defined. Velocity interferometers were used to record the high strain-rate response, while low strain rate data were collected using strain gauges. Although the current tests were conducted at a nominal velocity of ∼ 1.5 km/s, it is the test methodology that is being emphasized herein. Results of a three-dimensional experiment are also presented.