Effects of surface undulation on fatigue of wire arc additively manufactured ER70S-6 steel: numerical and analytical models
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
This paper addresses the modelling of the static and fatigue behaviour of as-built and machined wire arc additively manufactured (WAAM) steel, with particular focus on the effects of surface undulations, which arise due to process-induced irregularities in heat input, material deposition, and melt pool dynamics. Based on 3D laser scans of WAAM coupons, finite element (FE) models are developed and validated against experimental results obtained using digital image correlation (DIC). The FE method, though accurate, is computationally expensive, since very fine meshes are required to model the as-built undulating surfaces of the WAAM coupons. Therefore, two simplified analytical models, one based on bending and the other on surface curvature, are proposed for the local stress analysis of the WAAM coupons, allowing for the influence of undulating surface and material thickness. The proposed methods are shown to predict the local stresses in the WAAM steel with reasonable accuracy, achieving errors as low as approximately 8–9 %, while maintaining high computational efficiency. The obtained local stresses are further used for the prediction of the fatigue crack initiation location and fatigue life of WAAM steel, achieving good agreement with the experimental results. Two fatigue design classes of FAT 145 and FAT 135 with endurance limits of 270 MPa and 250 MPa, respectively, are derived for WAAM ER70S-6 steel using the proposed models.
Date Issued
2025-10-01
Date Acceptance
2025-08-01
Citation
Structures, 2025, 80
ISSN
2352-0124
Publisher
Elsevier
Journal / Book Title
Structures
Volume
80
Copyright Statement
© 2025 The Author(s). Published by Elsevier Ltd on behalf of Institution of Structural Engineers. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Subjects
3D printing
Analytical model
BEHAVIOR
COMPONENTS
CRITERIA
CRITICAL DISTANCES
Engineering
Engineering, Civil
High-cycle fatigue
Metal additive manufacturing
Numerical model
Science & Technology
SIMULATION
Stress concentration
Technology
WOHLER CURVE METHOD
WROUGHT
Publication Status
Published
Article Number
109878
Date Publish Online
2025-08-12