Compression Behavior of EBM Printed Auxetic Chiral Structures

Kadir Gunaydin*, Halit Süleyman Türkmen, Alessandro Airoldi, Marco Grasso, Giuseppe Sala, Antonio Mattia Grande

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

In this study, the cyclic compression and crush behavior of chiral auxetic lattice structures produced from titanium alloy (Ti6Al4V) metallic powder using electron beam melting (EBM) additive manufacturing technology is investigated numerically and experimentally. For material characterization and understanding the material behavior of EBM printed parts, tensile and three-point flexural tests were conducted. Log signals produced during the EBM process were investigated to confirm the stability of process and the health of the produced parts. Furthermore, a compressive cyclic load profile was applied to the EBM printed chiral units having two different thicknesses to track their Poisson’s ratios and displacement limits under large displacements in the absence of degradation, permanent deformations and failures. Chiral units were also crushed to investigate the effect of failure and deformation mechanisms on the energy absorption characteristics. Moreover, a surface roughness study was conducted due to high surface roughness of EBM printed parts, and an equation is offered to define load-carrying effective areas to prevent misleading cross-section measurements. In compliance with the equation and tensile test results, a constitutive equation was formed and used after a selection and calibration process to verify the numerical model for optimum topology design and mechanical performance forecasting using a non-linear computational model with failure analysis. As a result, the cyclic compression and crush numerical analyses of EBM printed Ti6Al4V chiral cells were validated with the experimental results. It was shown that the constitutive equation of EBM printed as-built parts was extracted accurately considering the build orientation and surface roughness profile. Besides, the cyclic compressive and crush behavior of chiral units were investigated. The regions of the chiral units prone to prematurely fail under crush loads were determined, and deformation modes were investigated to increase the energy absorption abilities.

Original languageEnglish
Article number1520
JournalMaterials
Volume15
Issue number4
DOIs
Publication statusPublished - 1 Feb 2022

Bibliographical note

Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Funding

Funding: Support for this work has been provided by the Scientific and Technological Research Council of Turkey (TUBITAK) under Fellowship Number 2214-A with application number 1649B031400937. The work has been also supported by Politecnico di Milano.

FundersFunder number
TUBITAK1649B031400937
Türkiye Bilimsel ve Teknolojik Araştirma Kurumu
Politecnico di Milano

    Keywords

    • Additive manufacturing
    • Auxetic
    • Chiral
    • EBM
    • Energy absorption
    • FEM

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