J. Varghese, G. Radig, D. Herkommer, and A. Dasgupta
University of Maryland
College Park, MD 20742
This paper introduces a hybrid test methodology, based on dynamic indentation, to determine the high strain rate properties of materials. A conical indentation test setup, with real time measurement of load and indent depth, is developed for this purpose. Tests are conducted to obtain the load ĘC displacement (P-h) curves at different loading rates. Non-linear dynamic finite element analysis (FEA), using an iterative inverse solution technique, is used to convert the experimental data into stress-strain curves at different strain rates. The inverse solution technique involves varying the stress-strain curves until the the load-displacement curves obtained from simulation matches the experimentally measured data.
Results indicate that the uni-axial dynamic characterization tests under-predict the material properties of the specimen, when compared to the indentation tests. This is important for the characterization of materials that experience localized plasticity; eg. Structures subjected to drop and impact.
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