Skeletonization-based beam finite element models for stochastic bicontinuous materials: Application to simulations of na
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Downloaded from https://www.cambridge.org/core. Tufts Univ, on 31 Jul 2018 at 09:53:06, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/jmr.2018.244
Skeletonization-based beam finite element models for stochastic bicontinuous materials: Application to simulations of nanoporous gold Celal Soyarslana) Chair of Solid Mechanics, School of Mechanical Engineering and Safety Engineering, University of Wuppertal, Wuppertal 42119, Germany
Hakan Argeso Department of Manufacturing Engineering, Atılım University, Ankara 06830, Turkey
Swantje Bargmann Chair of Solid Mechanics, School of Mechanical Engineering and Safety Engineering, University of Wuppertal, Wuppertal 42119, Germany (Received 10 May 2018; accepted 25 June 2018)
An efficient representative volume element generation strategy is developed in modeling nanoporous materials. It uses periodic 3D beam finite element (FE) models derived from skeletonization of spinodal-like stochastic microstructures produced by a leveled random field. To mimic stiffening with agglomeration of the mass at junctions, an increased Young’s modulus is assigned to the elements within the junction zone. The effective Young’s modulus, Poisson’s ratio, and universal anisotropy index are computed. A good agreement of the Young’s modulus predictions with those obtained from experimental results for phase volume fractions 0:20 , fB , 0:50 is observed. Moreover, the elastic anisotropy index of the generated beam networks shows sufficient proximity to isotropy. Finally, it is demonstrated that, as compared to the simulation statistics of voxel-FE models, for the beam-FE models over 500-fold computational acceleration with 250-fold less memory requirement is provided.
I. INTRODUCTION
Nanoporous materials made by dealloying present themselves as a stochastic open-cell ligament networks at nanoscale with solid volume fractions in between 0.25 and 0.50.1–4 High yield strength to phase volume ratio, large specific surface area, and electrocatalytic performance are among towering features popularizing their use in applications such as catalysts, sensors, opticalactive materials, mechanical actuators, fuel cell and microbalance electrodes, and coating for medical devices.2,5,6 Upon mechanical loading, a bending-dominated load transmission occurs among interconnected ligaments.7 Thus, the Gibson–Ashby scaling relation8 is frequently used with reference to their mechanical behavior. However, this leads to more than an order of magnitude over-prediction of the Young’s modulus especially with smaller solid volume fractions.4,9–15 This prediction gap is bridged by devising 3D finite element (FE)-based micromechanical analyses of representative volumes, see, e.g., Refs. 4 and 13. In Ref. 4, a representative volume element (RVE) is formed a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2018.244 J. Mater. Res., 2018
through 3D tomographic reconstructions using a dualbeam focused ion beam (FIB) a
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