Finite element modelling of defects in additively manufactured strut-based lattice structures

Echeta, Ifeanyichukwu; Dutton, Ben; Leach, Richard K.; Piano, Samanta

Abstract

Strut-based lattice structures produced by powder bed fusion are prone to characteristic manufacturing defects that alter both their form and surface texture. Most studies in the literature focus on a subset of commonly observed defects, typically radius variation and strut waviness; surface defects remain relatively unexplored. Furthermore, there remains a need for the development of a general finite element modelling framework that can implement a range of defects into any strut-based lattice design. This paper presents a modelling framework for implementing a range of both form and surface defects into finite element meshes of strut-based lattices. A signed distance function forms the foundation for this framework, upon which surface meshes can be modified and converted into tetrahedral meshes via open-source software. The paper demonstrates how radius variation, strut waviness, elliptical cross sections and surface defects can be modelled in lattice struts, for which intuitive mathematical definitions are provided. A parametric study is performed to assess the sensitivity of the compressive Young's modulus of BCCZ and octet-truss lattices to upskin and downskin surface defects. The results showed higher sensitivity in the octet-truss than in the BCCZ; both designs were more sensitive to downskin defects than upskin defects.

Citation

Echeta, I., Dutton, B., Leach, R. K., & Piano, S. (2021). Finite element modelling of defects in additively manufactured strut-based lattice structures. Additive Manufacturing, 47, Article 102301. https://doi.org/10.1016/j.addma.2021.102301

• Journal Article Type: Article
• Acceptance Date: Sep 7, 2021
• Online Publication Date: Sep 20, 2021
• Publication Date: Nov 1, 2021
• Deposit Date: Sep 16, 2021
• Publicly Available Date: Sep 21, 2022
• Journal: Additive Manufacturing
• Print ISSN: 2214-7810
• Electronic ISSN: 2214-8604
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 47
• Article Number: 102301
• DOI: https://doi.org/10.1016/j.addma.2021.102301
• Keywords: Industrial and Manufacturing Engineering; Engineering (miscellaneous); General Materials Science; Biomedical Engineering
• Public URL: https://nottingham-repository.worktribe.com/output/6242974
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S2214860421004607