A High Strain-Rate Investigation of a Zr-based Bulk Metallic Glass and an HTPB Polymer Composite

Abstract : High strain-rate tests are performed on LM-1 using a Split-Hopkinson Pressure Bar (SHPB) to investigate effects of L/D ratio and annealing. An ultra high-speed camera was also employed to record the deformation and failure processes of LM-1. The amorphous specimens exhibit a reduction in peak stress with reduced L/D ratio and failure at the specimen-insert interface, indicative of stress concentrations due to the difference in the specimen and insert diameters, while the annealed specimens exhibited extensive fragmentation. High strain-rate compression experiments are conducted on a hydroxy-terminated polybutadiene (HTPB) polymer and its composite using another modified SHPB for testing of soft materials. Results from the experiments on HTPB polymer indicate a transition in the polymer between low and high strain-rate sensitivity at 2100/s, along with axial splitting at strain-rates above 3000/s. On the other hand, reduced rate-sensitivity is observed in the HTPB composite, most likely due to the presence of numerous interfaces between the glass beads and the polymer binder.