Design of inserts for splitHopkinson pressure bar testing of low strain-to-failure materials. Exp Mech 2009;49:479e90

Abstract In the present study a new insert design is presented and validated to enable reliable dynamic me-chanical characterization of low strain-to-failure materials using the Split-Hopkinson Pressure Bar (SHPB) apparatus. Finite element-based simulations are conducted to better understand the effects of stress concentrations on the dynamic behavior of LM-1, a Zr-based bulk metallic glass (BMG), using the conventional SHPB setup with cylindri-cal inserts, and two modified setups—one utilizing conical inserts and the other utilizing a “dogbone ” shaped speci-men. Based on the results of these computational experi-ments the ends of the dogbone specimen are replaced with high-strength maraging steel inserts. This new insert-specimen configuration is expected to prevent specimen failure outside the specimen gage section. Simulations are then performed to validate the new insert design. Moreover, high strain-rate uniaxial compression tests are conducted on LM-1 using the modified SHPB with the new inserts. An ultra-high-speed camera is employed to investigate the changes in failure behavior of the specimens. Additional experiments are conducted with strain gages directly attached to the gage section of the specimens to determine accurately their dynamic stress–strain behavior