Investigating the dynamic response of heterogeneous mixtures with variable geometric complexity

The dynamic response of an energetic surrogate mixture of sugar and Polydimethylsiloxane (PDMS) / UV curing resin, subjected to uniaxial loading, is investigated. Of particular interest in this investigation are the fluctuations observed at the Hugoniot states of heterogenous mixtures. This research seeks to better understand what portion of these fluctuations can be attributed to the simple mechanical response of the meso-structure of the mixture. The approach is to build samples with increasing complexity, experimentally load them and simulate them, so that direct comparisons can be made. Samples were fabricated with a single sugar cube, and two sugar cubes with varying distances between them embedded within the binder material. After samples were built, the 3D geometry was obtained using XCT scans. PDV probes were focused at specified locations within the heterogeneous mixture so that a more direct comparison between experiments and simulations could be obtained. Experiments were performed in a one-dimensional plain strain configuration with shot velocities ranging between 79 m/s and 573 m/s. Velocity and some temperature measurements were made on the target. Numerical simulations are performed utilizing one-dimensional Lagrangian (KO) and three-dimensional Eulerian (CTH) approaches. The results indicate a systematic response signature superimposed on the Hugoniot plateau which is correlated to the geometry.