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Fundamental structure of steady plastic shock waves in metals

Molinari, A. and Ravichandran, G. (2004) Fundamental structure of steady plastic shock waves in metals. Journal of Applied Physics, 95 (4). pp. 1718-1732. ISSN 0021-8979. http://resolver.caltech.edu/CaltechAUTHORS:MOLjap04

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Abstract

The propagation of steady plane shock waves in metallic materials is considered. Following the constitutive framework adopted by R. J. Clifton [Shock Waves and the Mechanical Properties of Solids, edited by J. J. Burke and V. Weiss (Syracuse University Press, Syracuse, N.Y., 1971), p. 73] for analyzing elastic–plastic transient waves, an analytical solution of the steady state propagation of plastic shocks is proposed. The problem is formulated in a Lagrangian setting appropriate for large deformations. The material response is characterized by a quasistatic tensile (compression) test (providing the isothermal strain hardening law). In addition the elastic response is determined up to second order elastic constants by ultrasonic measurements. Based on this simple information, it is shown that the shock kinetics can be quite well described for moderate shocks in aluminum with stress amplitude up to 10 GPa. Under the later assumption, the elastic response is assumed to be isentropic, and thermomechanical coupling is neglected. The model material considered here is aluminum, but the analysis is general and can be applied to any viscoplastic material subjected to moderate amplitude shocks. Comparisons with experimental data are made for the shock velocity, the particle velocity and the shock structure. The shock structure is obtained by quadrature of a first order differential equation, which provides analytical results under certain simplifying assumptions. The effects of material parameters and loading conditions on the shock kinetics and shock structure are discussed. The shock width is characterized by assuming an overstress formulation for the viscoplastic response. The effects on the shock structure of strain rate sensitivity are analyzed and the rationale for the J. W. Swegle and D. E. Grady [J. Appl. Phys. 58, 692 (1985)] universal scaling law for homogeneous materials is explored. Finally, the ability to deduce information on the viscoplastic response of materials subjected to very high strain rates from shock wave experiments is discussed.


Item Type:Article
Additional Information:©2004 American Institute of Physics. Received 16 June 2003; accepted 20 November 2003. The research reported here was supported by the Army Research Office (Dr. B. LaMattina, Program Manager), which is gratefully acknowledged. G.R. acknowledges the support of DOE through Caltech’s ASCI/ASAP Center for the Simulation of Dynamic Response of Materials.
Subject Keywords:metals; shock wave effects; high-pressure effects
Record Number:CaltechAUTHORS:MOLjap04
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:MOLjap04
Alternative URL:http://dx.doi.org/10.1063/1.1640452
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5221
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:05 Oct 2006
Last Modified:26 Dec 2012 09:04

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