Uncertainty of Elastoplastic Material Parameters Calculated from the Spherical Indentation in the Macro Range

Abstract The applicability of three methods developed by finite element method (FEM) and proposed in the literature are studied on steel S355. Instrumented indentation tests using spherical indenters of radius 200 and 500 µm are performed in the macro range at depths of more than 6 µm. The results of the selected methods are compared with the tensile test. To evaluate the partially strongly varying results, the uncertainties of the calculated strain hardening exponent, n, and yield stress, Y, are estimated. Recommendations for an appropriated procedure of the indentation test are given. The machine compliance and the determination of the zero point of depth play an essential role. If the certain conditions are considered, the instrumented indentation tests can be used, in particular for investigations of specimens with inhomogeneous elastoplasticity.