Computer simulations and experiments to study the fracture of rods by flying plates

We have used HEMP3D to study the interaction of flying plates with a tungsten-alloy rod. HEMP3D is a three-dimensional elastic-plastic-hydrodynamic Lagrangian finite-difference computer simulation program with sliding interfaces. We have implemented a fracture model that treats both the initiation and growth of fractures. This model does not require the prespecification of fracture surfaces. Comparison of the results of computer simulations with a limited number of experiments indicated that the computer simulations were in good agreement with experiment as to the number and size of the broken pieces. We subsequently performed a number of computer simulations varying the mass and velocity of the flying plates. We compare the results of these simulations at a fixed time after impact to obtain the relative effectiveness of a given flying plate configuration. A configuration that produces many fragments and rotates them all out of alignment is given high ranking. It is intuitively likely that bigger and faster plates would rank higher than smaller, slower ones. In the experiments, the plates are accelerated by explosive. We have imposed a constraint on the flying plates that corresponds to a fixed amount of explosive, so the more massive plates move more slowly. 9 refs., 2 figs., 1more » tab.« less