LOCALIZATION OF STRAIN AND THE MELTING WAVE IN HIGH-SPEED PENETRATION

摘要

Localization of shear under high-speed penetration is shown to be accompanied by initiation of a melting wave. Transient, self-similar and steady-state problems of heating and melting of the material under idealized conditions of penetration are studied, and the role of plastic hardening is examined. A critical value of the discontinuity in the velocity in the shear bend is found: the melting wave arises independently of the hardening modulus if the discontinuity exceeds this point. Resistance to shear in the melting wave is shown to decrease drastically. This ensures the separation of the flow jets from the surrounding material. Thus, the plastic jet model of penetration is justified.