Sensitivity and uncertainty analysis of interfacial effect in SHPB tests for concrete-like materials

The Split Hopkinson Pressure Bar (SHPB) equipment has been widely used to measure the dynamic properties of concrete-like materials at high strain rate between 10s-1 and 103s-1. As we know, a crucial factor that influences the accuracy of SHPB tests is the interfacial effect between specimen and bars. In our work, interfacial effect was investigated and summarized into three types of parameters, i.e., interfacial friction coefficient, specimen diameter and specimen non-parallelism. A series of concrete-like (cement mortar) specimens with two different strengths were tested at three different strain rates on SHPB equipment, and the uncertainty of the interfacial effect was transformed into intervals of these three types of parameters. A numerical model was established in ABAQUS and verified to study the interfacial effect, then the sensitivity analysis of three types of parameters was undertaken to figure out a sensitivity ranking using the full factorial design method. The sensitivity analysis provides an effective measure to promote the experimental accuracy and it is meaningful for understanding the interfacial effect in SHPB tests. Moreover, uncertainty analysis was conducted to give an interval of dynamic response of SHPB tests based on a non-probabilistic interval analysis method. The uncertainty analysis can provide an effective estimation of SHPB experimental results considering the uncertainty of interfacial effect.