Material Failure and the Growth of Instabilities in Hollow Cylindrical Samples of Aluminum Shocked to 14Gpa and 50Gpa (U) [electronic resource].
- Washington, D.C : United States. Dept. of Energy. Office of the Assistant Secretary for Defense Programs, 1999.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 1,300 Kilobytes pages : digital, PDF file
- Additional Creators:
- Lawrence Livermore National Laboratory
United States. Department of Energy. Office of the Assistant Secretary for Defense Programs
United States. Department of Energy. Office of Scientific and Technical Information
- Understanding the surface stability of metals undergoing dynamic fracture at shock breakout is important to several applications in metals processing. The advantages of using the Pegasus II facility to investigate the phenomena occurring at shock break out are described. As an example of the data collected, we concentrate on brief descriptions of two experiments that compared the tensile failure, i.e. ''spall'', patterns in the presence of sinusoidal perturbations seeded on the free inner surface of cylindrical samples made of structural grade Al 6061.T6. These samples were subjected to ramped waves with shock pressures of 14 GPa and 50 GPa to observe the effect of pressure on the production of a type of volumetric failure that is mentioned here ''microspall.'' This failed region behind the exiting surface of the shock wave is comprised of a significant volume of low-density, probably granular, material. The failure mechanism, combined with the forces that cause inertial instability, leads to rapid pattern growth in the failed material, observable as density variations, as well as to pattern growth on the surface. Pattern growth was observed to vary with perturbation amplitude, wavelength, and shock pressure. Both increased pressure and increased amplitude were shown to destabilize a stable perturbation. Increasing the wavelength by a factor of 3 was shown to result in significantly slower growth of the pattern within the failed volume. The mechanisms leading to the formation of the spall volume and to the patterns are discussed briefly.
- Published through SciTech Connect.
7th International Workshop on the Physics of Compressible Turbulent Mixing, St. Petersburg (RU), 07/05/1999--07/09/1999.
Morgan, D.V.; Oona, H.; Anderson, W.E.; Fulton, R.D.; Stokes, J.; Oro, D.M.; Obst, A.W.
- Funding Information:
View MARC record | catkey: 14449276