Recovery of information on the depth-dependent profile of elastic FGMs from indentation experiments

Abstract

A perturbation technique is applied to construct the first-order perturbation model for the incremental indentation stiffness in normal frictionless indentation of an isotropic functionally graded medium (FGM) with a constant Poisson’s ratio and an in-depth variable elastic shear modulus. The FGM identification problem of determining the shear modulus function from the effective indentation shear modulus, which is measured as a result of indentation testing, is formulated and solved. It is shown that both the effective shear modulus and the relative adhesive (pull-off) force are sensitive to the type of material grading.