An energy-based method for flow property determination from a single-cycle spherical indentation test (SIT)

In this study, a method to determine the flow property from a single-cycle spherical indentation test was proposed, based on energy analysis and digital image correlation (DIC) measurements. The energy-based method (EBM) was analytically derived, and thus has a clear physical meaning and errors from finite element calculations and phenomenological summarization can be effectively avoided. Effectiveness of the EBM was verified through experiments on 11 kinds of metals, including steels, titanium alloys, aluminum alloys, and pure Ni. A comparative study was performed for EBM and its previous counterparts (including the empirically determined Haggag method, the analytically derived Gao-Kang method, as well as the numerically concluded Zhang method), and sources of errors in the previous methods were investigated. From a sensitivity analysis, it was found that stress-strain calculations from SITs with the new proposed EBM are not sensitive to the errors in proportional limit calculation or load-depth measurements, and thus the potentiality of EBM for engineering applications can be guaranteed.