DYMAT 2009
Volume 1, 2009
DYMAT 2009 - 9th International Conference on the Mechanical and Physical Behaviour of Materials under Dynamic Loading
Page(s) 485 - 490
Section Experimental Techniques
Published online 15 September 2009
DYMAT 2009 (2009) 485-490
DOI: 10.1051/dymat/2009069

Theoretical assessment of stress-strain curve estimates in Split Hopkinson Bar experiments

D. Mohr1, G. Gary1 and B. Lundberg2

1  Solid Mechanics Laboratory (CNRS-UMR 7649), École Polytechnique, 91128 Palaiseau, France
2  The Angström Laboratory, Uppsala University, Box 534, 75121, Sweden

Published online: 15 September 2009

The determination of the stresses and strains based on split Hopkinson pressure bar (SHPB) measurements is an important step in the identification of reliable experimental data on the mechanical behavior of materials at high strain rates. Modern SHPB systems provide accurate measurements of the forces and velocities at the boundaries of a dynamically loaded specimen, while approximations need to be made to obtain the stress-strain curve based on these measurements. Several formulas have been proposed in the past to estimate the stress-strain curve from dynamic experiments. Here, we make use of the theoretical solution for the waves in an elastic specimen to evaluate the accuracy of these estimates. It is found that it is important to avoid an artificial time shift in the processing of the experimental data. Moreover, it is concluded that the combination of the output force based stress estimate and the average strain provides the best of the commonly used stress-strain curve estimates in standard SHPB experiments.

© EDP Sciences 2009