Abstract
Recently, Richtmyer-Meshkov instability (RMI) experiments driven by high explosives and fielded with perturbations on a free surface have been used to study strength at extreme strain rates and near zero pressure. The RMI experiments reported here used impact loading, which is experimentally simpler, more accurate to analyze, and which also allows the exploration of a wider range of conditions. Three experiments were performed on tantalum at shock stresses from 20 to 34 GPa, with six different perturbation sizes at each shock level, making this the most comprehensive set of strength-focused RMI experiments reported to date on any material. The resulting estimated average strengths of 1200-1400 MPa at strain rates of 10^{7}/s exceeded, by 40% or more, a common power law extrapolation from data at strain rates below 10^{4}/s. Taken together with other data in the literature that show much higher strength at simultaneous high rates and high pressure, these RMI data isolated effects and indicated that, in the range of conditions examined, the pressure effects are more significant than rate effects.
Highlights
The ability of viscosity to reduce the growth rate of Richtmyer-Meshkov instabilities (RMI) in fluids has been studied for some time [1,2,3,4,5]
Our RMI metal-strength targets were machined by mounting a diamond tipped tool, at a radius of r 150 mm, to the spindle of an air-bearing lathe
The use of impact loading, as compared to high explosive loading in previous experiments, made for simpler and more precise data analysis as well as the ability to explore a wider range of conditions
Summary
The ability of viscosity to reduce the growth rate of Richtmyer-Meshkov instabilities (RMI) in fluids has been studied for some time [1,2,3,4,5]. This work builds and improves upon previous efforts that capitalized on the more experimentally accessible freesurface (Atwood number = –1) RMI configuration to quantitatively estimate strength at low pressure and rates up to at least 107/s [19,20,21,22]. The previous efforts used high explosive loading to generate the shock. This work reports RMI strength measurements using impact loading to improve the process. In the traditional fluid mechanics understanding, the original high spots invert and become low spots called bubbles. In the experiments on high strength solids in this work, the inversion does not progress that far in the time of interest, so Fig. 1 does not show traditional bubbles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
