Full-field validation of a thermo-mechanical model for directed energy deposition using IR thermography and stereo DIC

Kovšca, Dejan (author), Starman, Bojan (author), Govekar, Edvard (author), Mole, Nikolaj (author), Halilovič, Miroslav (author)

This paper presents a thermo-mechanical finite element (FE) modelling framework for laser-based directed energy deposition (DED-LB) that is validated and calibrated using a novel full-field, in-situ experimental approach. The measuring setup combines infrared (IR) thermography and stereo digital image correlation (DIC) to enable continuous, non-intrusive, full-field measurement of transient temperature and displacement fields on the substrate without interfering with the DED process. These measurements provide direct input for reliable model calibration and a consistent basis for full-field validation of both thermal and mechanical response of the numerical model. The calibrated FE model accurately reproduces the measured thermal histories and the evolution of substrate deformation throughout the process. Based on the validated model, the dominant deformation mechanisms are identified, highlighting the combined effects of thermal gradients, contraction of the solidifying deposited material, and mechanical boundary conditions. The study further introduces a new analytical bead-geometry modelling method that estimates the geometry of initial and overlapping beads without additional experiments and establishes a consistent link between realistic and simplified bead representations while preserving deposited mass and heat input. Comparative simulations demonstrate that simplified rectangular bead profiles can reduce computational cost by up to 70% with only minor loss of accuracy, making them suitable for parametric studies. Finally, different DED strategies are evaluated, showing that an inward-spiral strategy leads to the lowest substrate deformation and the most uniform residual-stress distribution, whereas unidirectional and bidirectional strategies produce larger deflections and stronger springback.

• Language: English
• Keywords: directed energy deposition, thermo-mechanical modelling, residual stress and deformation, digital image correlation
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2026
• Number of pages: 26 str.
• Numbering: Vol. 258, art. 104554
• PID: 20.500.12556/RUL-181709
• UDC: 004.9
• ISSN on article: 1872-6925
• DOI: 10.1016/j.finel.2026.104554
• COBISS.SI-ID: 275099395
• Publication date in RUL: 14.04.2026

Record is a part of a journal

• Title: Finite elements in analysis and design
• Publisher: Elsevier
• ISSN: 1872-6925
• COBISS.SI-ID: 23024645

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: usmerjeno nanašanje materiala, termo-mehansko modeliranje, zaostale napetosti in deformacije, korelacija digitalnih slik