The Feasibility of a Shear-Compression Kolsky Bar with Simultaneous Wave Arrival at the Sample
Technical Report,01 Oct 2018,01 Sep 2019
US Army Combat Capabilities Development Command Army Research Laboratory Aberdeen Proving Ground United States
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Improving armor materials requires a full understanding of the constitutive response of a material subjected to a multiaxial stress state at dynamic strain rates. This has proved almost impossible to measure dynamically. This report assesses the feasibility of one method to produce an axial wave and a shear wave that arrive at a sample simultaneously. The method uses a modified Kolsky bar apparatus with a pair of gun barrels, where one projectile creates an axial wave and the other a shear wave in the Kolsky bars. The waves are created at opposite ends of the apparatus and travel toward the sample from opposite directions. The time difference created by sending the signals to the valves, the opening of the valves, and the time the projectile spends moving down the gun barrel needs to be consistent enough to be corrected for, since the waves travel at different velocities. The model system built shows the error is too large and, thus, this method is not feasible.