Identification of elastic-plastic properties of metal materials by using the residual imprint of spherical indentation

In this paper, a novel inverse computation method is proposed to estimate the elastic-plastic properties of metal materials by using only the residual imprint of spherical indentation. The advantage of this method is that it does not need to know the entire loading history. The indentation experiment can be easily implemented on a hardness tester while the residual imprint can be measured using a 3D measuring laser microscope. We correlate the imprint snapshot with material constitutive parameters using proper orthogonal decomposition and parametric approximation, and then we solve the inverse problem using the “Interior-point” optimization algorithm. The effectiveness of this method is verified by application on 2099-T83 Al-Li alloys. Results show the inverse analysis gives well-posed solution of parameters of materials only when the penetration depth or the prescribed indentation load is sufficient, and the elastic-plastic properties obtained from indentation and uniaxial experimental data show good agreement. Besides, the sensitivity investigation indicates the use of weighting imprint obtained from different experiment loads is able to give a more stable and reliable result.