Extreme Dynamic Tension Theory and Its Application in the Dynamic Necking*

The extreme tension physics has brought a great interest in the national defense application where the dynamic fragmentation or cracking is common (i.e. ammunition casing explosion, penetration, etc.).  This is because the extreme tension physics reveals the typical particle behavior with the unique tension wave propagation during the extreme tension event, and it delivers a theoretical fundamental to understand the fragmentation behavior.  However the theory of extreme tension physics does not allow a direct application to the typical engineering problem due to the limited one-dimensional configuration and the uniaxial strain constraint (i.e. the extreme tension physics cannot handle the dynamic necking prior to the fragmentation). 

In this study, the nature of 2D extreme dynamic necking will be investigated using the 1D extreme tension theory with the use of a series MD (molecular dynamic) code simulation.  In more specifically, the particle behavior and the wave propagation pattern will be analyzed in order to understand the particle kinetics, thermodynamics, and mapping of the pressure profile during the extreme dynamic necking event (pull speed is in the range of several km/s).  This study is aiming to reveal the materials property mapping prior to the crack formation.