Simulation based evaluation of fixturing and substrate effects on distortion in laser wire DED process

Sammanfattning

Laser Wire Directed Energy Deposition (DED) is an emerging AM technology known for its ability to produce large metal components with material efficiency and design flexibility. However, one of the main challenges in adopting this technology is distortion and residual stress induced during the thermal cycling of the deposition process. These issues can compromise geometric accuracy, structural integrity, and the mechanical performance of the built components, particularly in aerospace applications where precision matters. This thesis focuses on investigating the laser wire DED process using a finite element simulation approach, with the aim of reducing substrate distortion and residual stresses through strategic fixturing and substrate designs. A simulation-based approach using Simufact Welding is used to analyze various clamping and substrate configurations. These configurations are evaluated according to established success criteria, which include axial deformation (Z-displacement), residual stress trends, and process stability. The findings indicate the predicted outcome on various fixturing and substrate configurations that can potentially reduce distortion by improving heat dissipation and mechanical support during and after deposition. A comparative analysis of different configurations showed distinct trends in how changes to boundary conditions and substrate design influence deformation behavior. The results offer valuable design strategies for reducing residual stress-induced failures and improving dimensional accuracy in DED-manufactured large components. In practical terms, this research offers a simulation workflow and practical guidelines for fixturing and substrate design, which supports a more reliable DED process in industrial settings, particularly for aerospace and high-performance structural applications. Overall, the study lays the foundation for future development and validation of more intricate multi-layer deposition by bridging the gap between simulation and real-world application.