Numerical Analysis of the Response of Thick Wires to Extreme Dynamic Electromechanical Loads.

Impact and shock wave events represent typical extreme dynamic loads of interest for accessing the response of materials and structures. Here, we focus on an intense electric current pulse as an extreme dynamic load. Experimentally, metallic samples were electromechanically loaded with currents up to 400 kA. For this purpose, a test rig containing a high-voltage pulsed power supply and high-performance switches was built. In this paper, we present an approach for modeling the response of thick metallic wire samples, with diameters on the order of millimeters, to extreme electromechanical loads sufficient for deformation and fragmentation, but not for material disintegration by wire explosion. The essential electrodynamic, thermodynamic, and mechanical aspects are considered, and a way to couple those physical regimes is suggested, which allows the use of numerical simulation based on the finite-element method to determine the material response. Simulations are employed to describe the time-dependent process of the structural and material behavior of thick wires. The focus here is on the structural mechanical behavior including bending or buckling before the onset of the wire explosion. The new approach for a simulation model is able to capture the basic experimental observations. [ABSTRACT FROM PUBLISHER]