Plate impact method for shock physics testing

Abstract

Dynamic loading experiments under extreme testing conditions yield much different mechanical and chemical responses in materials when compared to those found under static conditions. Engineering applications of shock physics including ballistic and explosive impact, as well as any other sort of high energy collision, are found in a range of industries such as armor and weapons. The extreme temperatures and pressures at which shock physics experiments are able to test can simulate the response of radioactive materials during the detonation of nuclear weapons. It is therefore critically important to these industries to have an understand of the plastic response of materials at high temperatures and strain rates. An understanding of material responses is especially important for applications whereby shear bands are generated under extreme high strain rate conditions, such as in automotive and aerospace structures.1‒4 The foregoing serves as the motivation to investigate the appropriate experimental techniques that test the material responses to these conditions. One of the most common methods of investigating the behavior of materials subjected to a continuous deformation at high strain rates on the order of 105107s-1 is to perform shear plate impact experiments.5‒7 In a general plate impact experiment, a gas gun launches a plate projectile towards a thin, circular specimen sandwiched between two additional plates.8 The flyer plate lies in between the projectile and the specimen, while the anvil plate lies behind the specimen. Often, the flyer plate itself is used as the projectile, making direct contact with the specimen. The projectile is guided by a key running through a keyway within the gas gun barrel, keeping it from rotating. A typical schematic of an experiment is depicted in Figure 1.