Ramp wave experiments on the Sandia Z accelerator provide a different approach to study the rapid compression response of materials at pressures, temperatures, and stress or strain rates not attainable in conventional shock experiments. Due to its shockless nature, the ramp wave experiment is often termed as an isentropic (or quasi-isentropic) compression experiment (ICE) and the analysis of ICE has been focused on determination of the isentropes. One objective of the current study is to show that ramp wave experiment can be used as a much more general material characterization tool for studying material behavior under high strain rates and pressures. The second objective is to suggest practical methodology to design the experiment and analyze experimental data. Numerical simulations were used to achieve these objectives. It is demonstrated that the ramp wave experiment is essentially a controlled-strain-rate material test. The strain rate can be varied through the rise time and shape of the ramp wave. The resultant stress-strain relation is a specific relation for a specific strain-rate history. The isentrope, which is a limiting case of such relations, may be approximated through a very low strain-rate loading path. Because of the rate dependence of the material behavior, each material point experiences different strain-rate loading paths. Lagrangian analysis requires information pertinent to a local Lagrangian material point. This information may be obtained through a pair of wave profiles measured at two very close, but essentially the same, Lagrangian points.
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Research Article| April 11 2007
Material characterization with ramp wave experiments
J. L. Ding;
J. L. Ding, J. R. Asay; Material characterization with ramp wave experiments. J. Appl. Phys. 1 April 2007; 101 (7): 073517. https://doi.org/10.1063/1.2709878
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