Bending behavior of octet-truss lattice structures : Modelling options, numerical characterization and experimental validation

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Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2021-07
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Mcode
Degree programme
Language
en
Pages
14
Series
Materials and Design, Volume 205
Abstract
Selective Laser Melting (SLM) technology has undergone significant development in the past years providing unique flexibility for the fabrication of complex metamaterials such as octet-truss lattices. However, the microstructure can exhibit significant variations due to the high complexity of the manufacturing process. Consequently, the mechanical behavior, in particular, linear elastic response, of these lattices is strongly dependent on the process-induced defects, raising the importance on the incorporation of as-manufactured geometries into the computational structural analysis. This, in turn, challenges the traditional mesh-conforming methods making the computational costs prohibitively large. In the present work, an immersed image-to-analysis framework is applied to efficiently evaluate the bending behavior of AM lattices. To this end, we employ the Finite Cell Method (FCM) to perform a three-dimensional numerical analysis of the three-point bending test of a lattice structure and compare the as-designed to as-manufactured effective properties. Furthermore, we undertake a comprehensive study on the applicability of dimensionally reduced beam models to the prediction of the bending behavior of lattice beams and validate classical and strain gradient beam theories applied in combination with the FCM. The numerical findings suggest that the octet-truss lattices exhibit size effects, thus, requiring a flexible framework to incorporate high-order continuum theories.
Description
Funding Information: We gratefully acknowledge the support of Deutsche Forschungsgemeinschaft (DFG) through the project 414265976 - TRR 277 C-01 and TUM International Graduate School of Science and Engineering (IGSSE), GSC 81. This work was partially supported by the Italian Minister of University and Research through the MIUR-PRIN projects “A BRIDGE TO THE FUTURE: Computational methods, innovative applications, experimental validations of new materials and technologies” (No. 2017L7X3CS) and “XFAST-SIMS” (No. 20173C478N). The authors would like to acknowledge the project “MADE4LO - Metal ADditivE for LOmbardy” (No. 240963) within the POR FESR 2014-2020 program. We also kindly acknowledge Eng. Alberto Cattenone and Prof. Stefania Marconi of the 3DMetal laboratory of the Department of Civil Engineering and Architecture of the University of Pavia for providing facilities for additive manufacturing and experimental testing ( http://www-4.unipv.it/3d/laboratories/3dmetalunipv/ ). We further acknowledge Academy ofFinland through the project Adaptive isogeometric methods for thin-walled structures (decision number 304122) as well as the August-Wilhelm Scheer Visiting Professors Program established by TUM International Center and funded by the German Excellence Initiative. The authors also gratefully acknowledge the Gauss Centre for Supercomputing e.V. ( www.gauss-centre.eu ) for funding this project by providing computing time on the Linux Cluster CoolMUC-2 and on the GCS Supercomputer SuperMUC-NG at Leibniz Supercomputing Centre ( www.lrz.de ). Finally, the authors gratefully acknowledge Giorgio Vattasso from LaborMet Due ( http://www.labormetdue.it/ ) for his technical support in obtaining CT scan images. Publisher Copyright: © 2021 The Author(s) Copyright: Copyright 2021 Elsevier B.V., All rights reserved.
Keywords
Additive manufacturing, Beam theories, Computed tomography, Finite Cell Method, Finite Element Method, Metamaterials, Octet-truss lattice, Strain gradient elasticity
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Citation
Korshunova, N, Alaimo, G, Hosseini, S B, Carraturo, M, Reali, A, Niiranen, J, Auricchio, F, Rank, E & Kollmannsberger, S 2021, ' Bending behavior of octet-truss lattice structures : Modelling options, numerical characterization and experimental validation ', Materials & design, vol. 205, 109693 . https://doi.org/10.1016/j.matdes.2021.109693