Experimental and Numerical Analysis of High Strain Rate Splitting-Tensile Tests

Splitting tensile concrete specimens were tested at strain rates of 10 to the power -7/sec to 10 to the power 2/sec in a low speed material test machine and in a 50.8-mm diameter Split Hopkinson Pressure Bar (SHPB). A comprehensive finite element method (FEM) analysis was conducted on the same test speciments. A high-speed framing camera was used to record the gross deformation and cracking during the fracture process in the SHPB tests. In addition, an ultra high speed image converter camera with equivalent framing rates of 10,000 to 1,000,000 frames per sec was used to record some of the early crack formations during the fracture process in the SHPB tests. Results of tensile strength versus strain rate are presented and compared with compressive strength at similar strain rates. These same tensile data are compared with strength data obtained using a fracture mechanics model. Computer generated crack patterns are presented and compared to experimentally observed crack patterns in the fracture of concrete at high strain rates.