The prediction of loads on penetrators into rock via the spherical cavity expansion approximation

A spherical cavity expansion (SCE) model for axial loads on penetrators into rock has been developed and used in the GNOME penetrator code to calculate a recent full-scale strategic earth penetrator test (SEPW) into sidewinder tuff. The 2-D target motion is approximated by the 1-D motion produced by an expanding spherical cavity which allows rapid calculations over a complete penetrator trajectory. The target response includes a region of tensile fracturing which has not been modeled in production continuum dynamics code calculations. One reason for the development of this model is the current interest in blunter nosed penetrators than those previously analyzed with cylindrical cavity expansion (CCE) load models. 12 refs., 7 figs.