Experimental Techniques

Abstract

This chapter is a summary of a few selected experimental techniques to acquaint you with measuring shock wave parameters. It gives physical insight into practical use of impedance matching for obtaining data from experiments. It is not an exhaustive description of techniques since that would be a book by itself!The ever-increasing capability in computer technology has lead to more sophisticated numerical modeling of physical phenomena that requires ever more accurate high strain rate experiments especially shock wave measurements. The demand is for faster (fraction of a ms) and more accurate measurements during the initial event as well as for relatively long times (a few ms) after the initial shock event. Thus upgrading and improving experimental diagnostics are continually important in shock wave physics. It is also important to use different experimental tools to validate material models. Explosive and Flyer Plate Shock Driver SystemsThe major difference in shock waves generated by the impact of flat flyer plates versus plane 1-D shocks generated by in-contact explosives is the pressure-distance profiles. Flyer plate impacts create a steady pressure over a distance x while incontact explosive systems have a quasi-triangular shape as illustrated in Fig. 4.1.The flyer-plate shock systems can be explosively driven or gas driven from a smooth bore gun. The flat-top shocks have constant P, T, u, and r for a few ms's. This allows the experimental parameters to be measured accurately with a variety of techniques. In contrast, explosive in-contact shock systems create a pressure pulse that varies in time (quasi-triangular shape). The pressure drop behind the