Using Richtmyer–Meshkov Instabilities to Estimate Metal Strength at Very High Rates
Recently, Richtmyer–Meshkov instabilities (RMI) have been proposed for studying strength at strain rates up to 107/s. RMI experiments involve shocking a metal interface that has geometrical perturbations that invert and grow subsequent to the shock. As these perturbations grow, their growth may arrest, or they may grow unstably and eventually fail. The experiments observe the growth and arrest to study the specimen’s yield (deviatoric) strength. Along these lines we first review some RMI experimental results on Cu. Next, the paper presents explicit Lagrangian simulations used to help interpret the Cu RMI results and infer the strength, i.e. flow stress, of the target metal. A Preston-Tonks-Wallace (PTW) constitutive model is modified to be more accurate at the strain rates accessed in the experiment. The advantages and disadvantages of RMI, as compared to the Rayleigh–Taylor (shockless) instabilities that are used more commonly to infer strength, are discussed. The advantages of using simple velocimetry measurements in place of radiography are also discussed.
KeywordsRichtmyer–Meshkov instabilities Shock High strain rate Strength Rayleigh–Taylor
We acknowledge the support of the pRad team in acquiring these data. In addition, we appreciate contributions to these experiments by members of the LANL MST-7 group where our Cu targets were machined and characterized by F. Garcia, B. Day and D. Schmidt.
This work was performed at Los Alamos National Laboratory, operated by the Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under contract DE-AC52-06NA25396. By acceptance of this article, the publisher recognizes that the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or to allow others to do so, for U.S. Government purposes.
- 3.Lebedev, A.I., Nizovtsev, P.N., Rayevsky, V.A., Solovyov, V.P.: Rayleigh–Taylor instability in strong media, experimental study. In: Young, R., Glimm, J., Boston, B. (eds.) Proceedings of the Fifth International Workshop on Compressible Turbulent Mixing (1996)Google Scholar
- 14.Buttler, W.T., Oro, D.M., Preston, D., Mikaelian, K.O., Cherne, F.J., Hixson, R.S., Mariam, F.G., Morris, C.L., Stone, J.B., Terrones, G., Tupa, D.: The study of high-speed surface dynamics using a pulsed proton beam. AIP Conf. Proc. 1426(1), 999–1002 (2012). http://dx.doi.org/10.1063/1.3686446 CrossRefGoogle Scholar
- 21.Holtkamp, D.B.: Survey of optical velocimetry experiments-applications of PDV, a heterodyne velocimeter. In: Kiuttu, G.F., Turchi, P.J., Reinovsky, R.E. (eds.) Proceedings of 2006 International Conference on Megagauss Magnetic Field Generation and Related Topics, pp. 119–128. IEEE, Santa Fe (2006). doi: 10.1109/MEGAGUSS.2006.4530668
- 23.Burton, D.E., Carney, T.C., Morgan, N.R., Runnels, S.R., Sambasivan, S.K., Shashkov, M.J.: A cell-centered Lagrangian hydrodynamics method for multi-dimensional unstructured grids in curvilinear coordinates with solid constitutive models. Los Alamos National Laboratory Report LA-UR-11-04995 (2011)Google Scholar
- 24.Dobratz, B.M., Crawford, P.C.: LLNL explosives handbook. Properties of chemical explosives and explosive simulants. Lawrence Livermore National Laboratory Report UCRL-52997 Change 2 (1985)Google Scholar
- 25.Lyon, S.P., Johnson, J.D.: Sesame: the Los Alamos National Laboratory equation of state database. Los Alamos National Laboratory Report LA-UR-92-3407 (1992)Google Scholar
- 27.Tonks, D., Zurek, A., Thissell, W., Vorthman, J., Hixson, R.: The Tonks ductile damage model. Los Alamos National Laboratory Report LA-UR-03-0809 (2002)Google Scholar
- 29.Tonks, D.L.: Percolation wave propagation, and void link-up effects in ductile fracture. J. Phys. IV 4(C8), C8-665–C8-670 (1994)Google Scholar
- 31.Tonks, D.L., Bronkhorst, C.A., Bingert, J.F.: Inertial effects in dynamical ductile damage in copper. Los Alamos National Laboratory Report LA-UR-11-05803 (2011)Google Scholar