Origin of Striations Due to Mechanical Effects in Fast Wire Explosions

Abstract

The suggestion that mechanical oscillations in the solid wire are in part responsible for the production of striations observed in a class of wire explosions is investigated using the dispersion relation for elastic waves in isotropic solid cylinders. It is proposed that these oscillations arise due to the transient nature of the electrical energy deposition and that axial waves originate at points of discontinuities such as impurities and grain boundaries. Numerical solutions are obtained using the first shear‐ and dilatationalmode cutoff frequencies, and the wave numbers of these and standing waves are presented as a function of Poisson's ratio. Experimental data on the average distance between striations and new data are found to lie within the range predicted by the theoretical analysis.