Skeletonization, Geometrical Analysis, and Finite Element Modeling of Nanoporous Gold Based on 3D Tomography Data

• Main Authors: Claudia Richert, Norbert Huber
• Format: Article
• Language: English
• Published: MDPI AG 2018-04-01
• Series: Metals
• Subjects: nano-porous metal; mechanical behavior; 3D structural modeling; skeletonization; 3D FIB-SEM tomography
• Online Access: http://www.mdpi.com/2075-4701/8/4/282

Various modeling approaches simplify and parametrize the complex network structure of nanoporous gold (NPG) for studying the structure–property relationship based on artificially generated structures. This paper presents a computational efficient and versatile finite element method (FEM) beam model that is based on skeletonization and diameter information derived from the original 3D focused ion beam-scanning electron microscope (FIB-SEM) tomography data of NPG. The geometrical skeleton network is thoroughly examined for a better understanding of the NPG structure. A skeleton FEM beam model is derived that can predict the macroscopic mechanical behavior of the material. Comparisons between the mechanical response of this skeleton beam model and a solid FEM model are conducted. Results showed that the biggest-sphere diameter algorithm implemented in the open-source software FIJI, commonly used for geometrical analysis of microstructural data, overestimates the diameter of the curved NPG ligaments. The larger diameters lead to a significant overestimation of macroscopic stiffness and strength by the skeleton FEM beam model. For a parabolic shaped ligament with only 20% variation in its diameter, a factor of more than two was found in stiffness. It is concluded that improved algorithms for image processing are needed that provide accurate diameter information along the ligament axis.