Three-dimensional anisotropic mechanical model for additively manufactured metals
File(s)
Published version
Author(s)
Zhou, Jingsheng
Zhang, Ruizhi
Gardner, Leroy
Type
Journal Article
Abstract
This paper presents a systematic approach to simulating the three-dimensional anisotropic mechanical behaviour of additively manufactured (AM) metals. The approach combines Hooke's law with Hill's yield criterion, the associated plastic flow rule and anisotropic strain hardening, and provides a practical calibration method for all free model parameters. All free model parameters can be calibrated by three tensile coupon tests, with loading applied at different orientations relative to the print layer direction, under the assumption of transverse isotropy.
The approach is implemented numerically using a User Subroutine in Abaqus and validated against a wide range of tests on AM steel and stainless steel coupons, both with and without surface undulations. The results show good agreement and improved accuracy compared to the default Abaqus method. The improved performance is attributed to the fact that the anisotropic yielding behaviour at the onset of yielding can differ significantly from that at large plastic strains; this behaviour is captured in the proposed approach but cannot be captured by Hill's yield criterion with a constant set of free model parameters.
The influence of surface undulations, an inherent feature of as-built AM materials, on fracture behaviour is also analysed. Surface undulations disrupt stress flow paths and generate localised stress and strain concentrations, leading to earlier fracture initiation. Depending on the material properties, specimen orientation and the extent of the surface undulations, fracture may initiate anywhere between the cross-section centre and the surface, in contrast to smooth coupons, where fracture initiates at the cross-section centre.
The approach is implemented numerically using a User Subroutine in Abaqus and validated against a wide range of tests on AM steel and stainless steel coupons, both with and without surface undulations. The results show good agreement and improved accuracy compared to the default Abaqus method. The improved performance is attributed to the fact that the anisotropic yielding behaviour at the onset of yielding can differ significantly from that at large plastic strains; this behaviour is captured in the proposed approach but cannot be captured by Hill's yield criterion with a constant set of free model parameters.
The influence of surface undulations, an inherent feature of as-built AM materials, on fracture behaviour is also analysed. Surface undulations disrupt stress flow paths and generate localised stress and strain concentrations, leading to earlier fracture initiation. Depending on the material properties, specimen orientation and the extent of the surface undulations, fracture may initiate anywhere between the cross-section centre and the surface, in contrast to smooth coupons, where fracture initiates at the cross-section centre.
Date Issued
2026-10-01
Date Acceptance
2026-06-13
Citation
Journal of Constructional Steel Research, 2026, 245
ISSN
0143-974X
Publisher
Elsevier BV
Journal / Book Title
Journal of Constructional Steel Research
Volume
245
Copyright Statement
© 2026 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Publication Status
Published
Article Number
110530
Date Publish Online
2026-06-26