Elastic-plastic frictionless indentation analysis of a functionally graded vitreous enameled steel plate by a rigid spherical indenter

Elastic-plastic frictionless indentation of a functionally graded (FG) vitreous enameled steel plate with finite dimensions by a rigid spherical punch is studied in this paper. The problem is studied both experimentally and by using ABAQUS finite element package. The results obtained from ABAQUS simulations are compared to experimental results to check the validity of the ABAQUS model. In the simulations, the plastic deformation of the constituting phases of the plate is taken into account by using a volume fraction based model called TTO model. The validity of the TTO estimation of the modulus of elasticity is examined and verified by nano-indentation technique. The ABAQUS model is used to conduct a parametric analysis on the effect of parameters such as plate dimensions and thickness, indenter diameter and material properties distribution on the force-indentations curves of the plate and stress distribution underneath the punch. The simulations show that increasing the overall stiffness of the graded medium increases the stress mismatch at the interface of the plate constituting layers regardless of the layers thicknesses. In addition, the acquired results illustrated that for plates with similar thickness and material property distribution, changing the span does not affect the force-indentation curves.