Filamentary electromechanical breakdown

A breakdown mechanism is proposed in which a filamentary-shaped crack propagates through a dielectric, releasing both electrostatic energy and electromechanical strain energy stored in the material due to the applied electric field. The mechanism predicts a breakdown strength which is proportional to the fourth root of Young's modulus and a time to breakdown comparable with that taken for a sound wave to cross the dielectric ( approximately=0.1 mu s in 25 mu m thick polyethene films). Analysis of previously unexplained results of M. Hikita et al. (1985) on thin films of polyethylene yields good agreement with the proposed mechanism and a filament radius which is comparable to the gross morphological features of the dielectric.>