Development of a multi-section striker for split Hopkinson bar experiments and numerical simulations

Abstract
High strain rate testing is essential in the development of new materials under high dynamic loading conditions. Often, these new materials are very expensive and of limited quantities. For high dynamic loading using the split Hopkinson apparatus, the idea of using a striker that produces multiple strain rates in one test was investigated. The concept consists of using a multi-section striker with two different diameters to produce two strain rates using a single test sample. To test the concept, a first striker having two equal-length sections of different diameters was used and the results looked promising. A second striker made of several equal-length sections of two different diameters was tried. Results obtained confirm the usefulness of the approach, but preliminary results needs to be analyzed carefully to optimize the striker design. Numerical simulation using the hydrodynamic finite element code LS-DYNA was used to model the split Hopkinson bar and striker and contribute in the understanding of results.