Single-test evaluation of directional elastic properties of anisotropic structured materials

TL;DR

This paper introduces a novel single-test method using the virtual fields approach to determine all six elastic stiffness parameters of 2D anisotropic materials, simplifying experimental procedures.

Contribution

It presents a new methodology that identifies all anisotropic elastic parameters from one test without stress data, enhancing efficiency and accuracy.

Findings

Method accurately estimates stiffness parameters from synthetic data.

Experimental validation confirms effectiveness on additively manufactured specimens.

Reduces experimental complexity for anisotropic material characterization.

Abstract

When the elastic properties of structured materials become direction-dependent, the number of their descriptors increases. For example, in two-dimensions, the anisotropic behavior of materials is described by up to 6 independent elastic stiffness parameters, as opposed to only 2 needed for isotropic materials. Such high number of parameters expands the design space of structured materials and leads to unusual phenomena, such as materials that can shear under uniaxial compression. However, an increased number of properties descriptors and the coupling between shear and normal deformations render the experimental evaluation of material properties more challenging. In this paper, we propose a methodology based on the virtual fields method to identify six separate stiffness tensor parameters of two-dimensional anisotropic structured materials using just one tension test, thus eliminating the need for multiple experiments, as it is typical in traditional methods. The approach requires no stress data and uses full-field displacement data and global force data. We show the accuracy of our method using synthetic data generated from finite element simulations as well as experimental data from additively manufactured specimens