Explosive magnetic liner systems to study dynamic strength of materials

Abstract

AbstracfTo study dynamic strength of materials according to the initial liner perturbation'growth in Rayleigh-Taylor insta-bility development, three-layer liner systems driven by azimuthal magnetic field pressure have been suggested. This paper demodtrates that 0.4-m-diameter disk EMG ensuring currents up to -70 MA can be used for this pur-pose. In the three-layer liner systems, the liner shock-free loading to more than 1 Mbar pressures is therewith possi-ble, with the pressures rising for times longer than 1 ps or longer than 0.3 ps in different systems. Here the shock loading of the liners under study is possible up to 3 -4 Mbar pressures.Examples of 2D computations of the initial perturbation growth in the liners under study at shockfree and shock pressures up to 1 Mbar, strain rates up to 10' sec-', and strains up to 200 % are given.

Results and Prospects of Material Strength Studies on Electrophysical Facilities Based on Perturbation Growth in Liner Systems

“…Magnetically imploded cylindrical liners can be used to study dynamic shear strength properties of materials based on the growth of initial perturbations during the RayleighTaylor instability development in liner systems [1][2][3][4][5][6][7]. High-current capacitor banks (Pegasus-2, Shiva Star, Atlas, peak currents I max = 6 y 30 MA) and disc explosive magnetic generators (DEMGs, I max = 20 y 70 MA) are capable of driving cylindrical liner systems to a wide range of material pressures from~1 GPa [2,3] to hundreds of GPa [5].…”

“…High-current capacitor banks (Pegasus-2, Shiva Star, Atlas, peak currents I max = 6 y 30 MA) and disc explosive magnetic generators (DEMGs, I max = 20 y 70 MA) are capable of driving cylindrical liner systems to a wide range of material pressures from~1 GPa [2,3] to hundreds of GPa [5]. Numerical simulations of the experimental perturbation growth make it possible to test different dynamic strength models [3,7].…”

“…As a result, VNIIEF suggested using cylindrical ponderomotive units (PU) with multilayer liner systems [4,5] that preclude Joule heating of the materials being tested. Such liner systems were tested in the RHSR-1,2 (Russian High Strain Rate) experiments with 0.4 meter diameter DEMGs [6].…”

“…The 0.4 meter diameter DEMGs equipped with an electrically exploding foil opening switches (FOS) in similar devices [5] are capable of compressing Cu liners to P | 120 GPa without shock and to hundreds of GPa with shock waves; at such pressures, materials start melting. In accordance with preliminary calculations, Atlas is capable of shock and shockless copper compression in similar liner systems to~200 GPa and7 0 GPa, respectively.…”

“…1, left) of rapidly growing perturbation amplitudes in the liners. At VNIIEF, such simulations are performed with a 1D (MHD) n code developed on the basis of the UP technique [8] and 1D MHD approximation to simulate different pulse power systems and loads [2][3][4][5][6][7]9]. Such simulations use prior 2D simulation data.…”