6 - Shock concepts and material effects

Abstract

There are numerous examples in both the natural and applied worlds where shock compression and related phenomena play an important role. The montage shown in Fig. 1 highlights some of these, which span many orders of magnitude in pressure and length scale. At the lowest length scale, for example, shock compression is used to generate lattice-level defects as a means to increase the fatigue life of metal components. The technique, known as laser shock peening, modifies the near-surface region of a material, where the behavior of dislocations can be profoundly different than that at low strain rates. Shock also features prominently in the design of materials for protective applications. Intersection with advanced manufacturing in particular enables the tailoring of shock energy absorption to ultimately mitigate damage to structures and biological systems. Moving too much higher pressures, shock finds use as a tool to generate and study extreme states of matter relevant to energetic systems and inertial fusion schemes. Outstanding questions still remain regarding the effect of strength under such intense loading, especially in the case of mixed or partial melt conditions. And lastly, at the planetary scale, the shock has played an instrumental role in shaping the make up of the early solar system and accessing conditions within planetary bodies. Besides being used to study the makeup of asteroids (e.g., Deep Impact spacecraft in 2005), choreographed impacts have also been explored as a mechanism for asteroid redirection, as shown recently through the collision between the DART spacecraft and the Dimorphos asteroid in 2022.