Dynamic Response of an Alternative Tissue Simulant, Physically Associating Gels (PAG)

Report No. ARL-RP-136
Authors: Paul Moy; Tusit Weerasooriya; Thomas F. Juliano; Mark R. VanLandingham; Wayne Chen
Date/Pages: September 2006; 14 pages
Abstract: Recent work on formulating alternatives to ballistic gelatin, a soft tissue simulant, has lead to the development of physically associating gels (PAG). Ballistic gelatin impact response has been traditionally used to test and evaluate firearms and bullets but it does have some drawbacks, such as lacking consistency in its viscoelastic properties due to variability during the fabrication process, short shelf-life, and deterioration under prolonged usage at room temperature. PAG offers advantages such as the ability to tailor desired properties, a narrow range of viscoelastic properties, storage at room temperature, and superior environmental stability compared to ballistic gelatin. However, like ballistic gelatin, the material response and failure behavior at high rates are still not completely understood. High rate (~2500/s) compression experiments were conducted on ballistic gelatin and two types of PAG using a modified split-Hopkinson bar under dynamic equilibrium at constant strain rates using a pulse-shaping technique. Aside from these experimental conditions, considerations have been taken regarding the radial inertia effects that are typically observed during Hopkinson bar experiments of compliant materials such as gels. In addition to high rate experiments, stress-strain behavior of these materials at an intermediate strainrate (1/s) was also obtained. In this report, the test methodology used for the split-Hopkinson bar experiments is discussed, and the stress-strain behavior of ballistic gelatin and PAG are presented and compared.
Distribution: Approved for public release
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Last Update / Reviewed: September 1, 2006