Fast inversion algorithm for identification of elastoplastic properties of power hardening materials from limited spherical indentation tests

An inverse problem of identification of the elastoplastic properties of power hardening engineering materials from limited spherical indentation measurements is studied. A fast algorithm for reconstruction of the Ramberg-Osgood curve sigma(i) = sigma(0)(e(i)/e(0))(kappa), with the strain hardening exponent kappa is an element of (0, 1), is proposed. The main distinguished feature of this algorithm is that the only two output measured data , i=0,1, i.e. discrete values of the penetration depth (alpha(i)) and the loading force (P-i), are required for the reconstruction of the unknown Ramberg-Osgood curve. The first measured data corresponds to pure elastic deformations, and the second one to one of the plastic deformations. The second advantage of the proposed algorithm is its well-conditionedness, different from parametrization algorithms proposed in previous studies. Numerical examples related to applicability and enough accuracy of the proposed approach are presented for the noise free and noisy data. (C) 2011 Elsevier Ltd. All rights reserved.