Chapter 2 - Behavior of Granular Media Under High Strain-Rate Loading

Abstract

Understanding of the high-strain-rate (HSR) behavior of granular media is an imperative aspect of the fundamental physics of rapid penetration in these materials. The global response of granular media to rapid monotonic loading has conventionally been studied using modified geotechnical apparatus and other setups adapted from HSR testing of engineered materials. More recently, in realization of the role of finer scales in the global response, pioneering tests have been devised to explore these underlying scales. A wealth of knowledge has accumulated from these studies. In this chapter, a review of the response of sand under HSR loading is presented. The response observed in HSR uniaxial compression tests, split Hopkinson pressure bar (SHPB) tests, and triaxial tests is investigated. The effects of strain rate, initial void ratio, confining pressure, saturation, shape, and size of grains, along with grain mineralogy on the global scale, as well as the finer underlying scales, are discussed. A brief summary of the response of sand to shock loading is also presented. The review is aimed to serve as an introduction to the following chapters, which explore the response of granular media to rapid penetration.