10.1 Introduction

Split Hopkinson bars have been widely used for the characterization of dynamic behavior of engineering materials such as the dynamic flow stress of ductile metals ^{[[GRA 00]]}. As briefly described in the next section, these devices rely on the stress wave propagation in elastic bars to apply dynamic load on a specimen and to measure the loading and deformation histories in the specimen. This principle of using stress waves to detect mechanical events remotely was originally introduced by Hopkinson ^{[[HOP 14]]} and has become an established method in the data reduction of various split Hopkinson bar tests. Recently, in addition to the material coupon tests for material properties, the stress wave loading/detection principles are employed to characterize the dynamic response of various structures. In this article, we first briefly introduce the split Hopkinson bar method and the utilization of stress waves in this experimental technique. Then we review some of the recent applications of different versions of the split Hopkinson bars in three specific areas: (1) the determination of dynamic fracture behaviors of notched samples, (2) the determination of the biaxial flexural strength of thin brittle sheets and (3) the examination of the dynamic response of micromachined structures. In each area, unique challenges are encountered and specific treatments are needed to obtain valid results.