Elastic behavior analysis of multilayers by finite element method

Abstract

Abstract We studied the elastic properties of free-standing multilayered systems using finite element analysis with a rigid spherical indenter. To model and simulate the elastic response of these systems a 2-dimensional axisymmetric solid model was used. In particular, multilayered systems with a total thickness of 10 [μm] and composed by a periodic bilayer array were studied. The bilayers thickness in each multilayered system, as well as the isotropic elastic constants (Young´s modulus and Poisson´s ratio) of each thin film, were fixed to be constant in all the cases. The influence on the mechanical properties of different relative thickness ratios (from 0.11 up to 9) between the two films in the bilayer was carefully studied. Our results indicated that changes in the relative thickness ratios can produce considerable changes in the elastic mechanical response of the multilayered systems, observing important variations up to 19% (for displacements lower than 10% of the first film thickness) on the magnitude of the effective Young´s modulus. The interplay between the structural properties of the layers gives place to the nonlinear behavior of the Young modulus as a function of the volume fraction of the different layers. Due to the non-homogenous nature of the system, a strong dependence of the sample Young´s modulus with respect to the indentation depth was observed. This work contributes to qualitatively understand the impact of different characteristics of multilayered systems, such as the elastic properties and the proportion of the composing materials, on its elastic behavior.