SPLIT HOPKINSON PRESSURE BAR TECHNIQUES FOR CHARACTERIZING SOFT MATERIALS

EFICIENT USAGE OF SOFT MATERIALS UNDER IMPACT LOADING CONDITIONS REQUIRES ACCURATE AND RELIABLE DESCRIPTIONS OF THE HIGH-RATE MECHANICAL RESPONSES OF SUCH MATERIALS, WHICH MOTIVATES RECENT DEVELOPMENT OF VALID AND E±CIENT DYNAMIC EXPERIMENTAL TECHNIQUES. SPLIT HOPKINSON PRESSURE BAR (SHPB) HAS BEEN EXTENSIVELY USED TO CHARACTERIZE DYNAMIC BEHAVIOR OF METALLIC MATERIALS, BUT LESS FOR SOFT MATERIALS BECAUSE OF EXPERIMENTAL UNCERTAINTIES ASSOCIATED WITH SOFT MATERIAL CHARACTERIZATION. THIS PAPER FIRST PRESENTS MAJOR CHALLENGES ENCOUNTERED IN HOPKINSON BAR EXPERIMENTS ON SOFT MATERIALS, INCLUDING WEAK TRANSMITTED SIGNALS, DYNAMIC STRESS EQUILIBRIUM, AND CONSTANT STRAIN RATE, AND THEN SUMMARIZES RECENT RESEARCH E®ORTS IN THE MODIFICATIONS TO THE CONVENTIONAL SHPB FOR OBTAINING VALID AND ACCURATE STRESS-STRAIN DATA FOR SOFT MATERIALS.