Parametric optimization-based design and testing of 3D printed stainless steel circular X-joints
Author(s)
Zuo, Wenkang
Chen, Man-Tai
Zhao, Ou
Gardner, Leroy
Type
Journal Article
Abstract
The integration of topology optimization (TO) and metal 3D printing offers transformative opportunities for the design and fabrication of steel joints in spatial structures. This study develops a parametric joint TO-based design workflow, incorporating subdivision surface technology, the Bi-directional Evolutionary Structural Optimization (BESO) algorithm and advanced re-engineering techniques. Four X-joints for connecting circular tubes were optimized and then fabricated using Selective Laser Melting (SLM) with 316 L austenitic stainless steel powder. To characterize the mechanical properties of the printed material, uniaxial tensile coupon tests were conducted in five loading orientations. The 3D printed steel optimized X-joints were tested under axial compression, with the deformations and the strains captured using 3D Digital Image Correlation. The structural response was assessed in terms of strain distribution, load-deformation behavior, joint strength and ductility, as well as failure mode. The results demonstrate that the 3D printed TO designed X-joints exhibit a more uniform distribution of stress, superior ductility and more efficient load transfer compared to conventional tubular joints. This excellent structural performance is due to the inherent high ductility of SLM-fabricated 316 L stainless steel, the smooth geometric transitions achieved by means of subdivision surface technology, and the optimized material layout from BESO-based TO. The findings validate the feasibility of 3D printing TO designed joints for next-generation structural systems, with potential benefits in structural performance, fabrication efficiency and design flexibility.
Date Issued
2026-04-15
Date Acceptance
2026-01-09
Citation
Engineering Structures, 2026, 353 (Part A)
ISSN
0141-0296
Publisher
Elsevier BV
Start Page
122148
End Page
122148
Journal / Book Title
Engineering Structures
Volume
353
Issue
Part A
Copyright Statement
Copyright © 2026 Elsevier Ltd. This is the author’s accepted manuscript made available under a CC-BY licence in accordance with Imperial’s Research Publications Open Access policy (www.imperial.ac.uk/oa-policy)
License URL
Publication Status
Published
Article Number
122148
Date Publish Online
2026-02-02