The simulation provides valuable insights for materials design and engineering codes. We are on the threshold of bringing experiment and engineering together to provide insight into the fundamental physics of materials. Atoms respond according to Newton's equations of motion. The model shows how the atoms slip at an angle to the face of the crystal along preferred directions. As the stress is relieved, the slight slippage leaves behind planes that appear to be one notch out of arrangement.
Slight fluctuations lead the shock along four planes, leaving cubic fault lines.
Molecular dynamics studies, especially the effects of shock waves, are fundamental to improving the physics and engineering codes necessary for the nation's nuclear weapons stockpile stewardship program. While previous calculations modeled one tiny corner of a cube and hinted at a single slip fault, the new model represents a large enough cross-sectional area to see definitively the mosaic pattern of slippage. Advances in computing power and the molecular dynamics code developed at the Laboratory recently have made large, 3-D simulations possible. Even with available massively parallel computers, the current model represents a wave passing through a cube only a few millionths of a meter across in less than a nanosecond. Nevertheless, the calculations bring physicists one step closer to marrying computation and engineering.