Title: Coupled Topology and Process Optimization in Powder Bed Fusion Additive Manufacturing

Authors: Matthew J. Ireland, Brett Ellis, Masoud Rais-Rohani

DOI: 10.33599/nasampe/s.24.0104

Abstract: Large thermal-gradient additive manufacturing (AM) processes, such as powder bed fusion (PBF), exhibit process-dependent microstructures and properties that are not captured by traditional topology optimization (TO) design methods. The process-agnostic functionality of TO excludes valuable process-structure-property relationships from optimum design search and raises doubts about the validity of TO results when manufactured. This work addresses these shortcomings by implementing a coupled topology and process optimization algorithm for PBF AM. The algorithm augments a density-based TO search technique with the PBF process simulation model developed by AlphaSTAR Corporation to calculate as-solidified porosity. Mean porosity and volumetric energy density are utilized as objective criteria in a sequentially-coupled process optimization step that seeks optimum manufacturing parameters for a given TO solution. Isotropic elastic moduli are derived via a Mori-Tanaka homogenization scheme, and the resultant material property distribution is utilized to pose a new process-informed TO design problem. This procedure continues iteratively until discrepancies between as-designed and as-manufactured performance are minimized. For traditionally symmetric TO design solutions, the designs presented in this work are parameter-dependent and exhibit asymmetry in the build direction. Critically, a numerical comparison of process-agnostic and process-informed TO solutions shows performance improvements of up to 46 % achieved by the algorithm.

References: 1. A. T. Gaynor and J. K. Guest, “Topology optimization considering overhang constraints: Eliminating sacrificial support material in additive manufacturing through design,” Struct. Multidiscip. Optim., vol. 54, no. 5, pp. 1157–1172, 2016 doi.org/10.1007/s00158-016-1551-x 2.M. Langelaar, “An additive manufacturing filter for topology optimization of print-ready designs,” Struct. Multidiscip. Optim., pp. 871–883, 2017 doi.org/10.1007/s00158-016-1522-2 3.Y. Mass and O. Amir, “Using a virtual skeleton to increase printability of topology optimized design for industry-class applications,” Comptes Rendus - Mec., vol. 346, no. 11, pp. 1104–1121, 2018 doi.org/10.1016/j.crme.2018.08.005 4.M. Langelaar, “Combined optimization of part topology, support structure layout and build orientation for additive manufacturing,” Struct. Multidiscip. Optim., vol. 57, no. 5, pp. 1985–2004, 2018 doi.org/10.1007/s00158-017-1877-z 5.I. Osezua, et al. ""Topology optimization for metal additive manufacturing: current trends, challenges, and future outlook."" Virtual and Physical Prototyping 18.1 (2023) doi.org//10.1080/17452759.2023.2181192. 6.B. Torries, S. DorMohammadi, F. Abdi, S. Thompson, and N. Shamsaei, “Topology optimization of an additively manufactured beam,” in Solid Freeform Fabrication 2017: Proceedings of the 28th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2017, 2020, pp. 2263–2272. 7.K. K. Yang, J. H. Zhu, C. Wang, D. S. Jia, L. L. Song, and W. H. Zhang, “Experimental validation of 3D printed material behaviors and their influence on the structural topology design,” Comput. Mech., vol. 61, no. 5, pp. 581–598, 2018 doi.org/10.1007/s00466-018-1537-1 8.M. P. Bendsøe and O. Sigmund, “Material interpolation schemes in topology optimization,” Arch. Appl. Mech., vol. 69, no. 9–10, pp. 635–654, 1999 doi.org/10.1007/s004190050248 9.E. Malekipour and H. El-Mounayri, “Common defects and contributing parameters in powder bed fusion AM process and their classification for online monitoring and control: a review,” Int. J. Adv. Manuf. Technol., vol. 95, no. 1–4, pp. 527–550, 2018 doi.org/10.1007/s00170-017-1172-6 10.A. Laohaprapanon and V. Ben, “Study of the Optimized Parameters of Stainless Steel 316L Powder for Rapid Prototyping Based on Selective Laser Melting Technique,” Rapid Prototyp. J., vol. 13, no. 4, pp. 196–203, 2011 11.G. Allaire and L. Jakabčin, “Taking into account thermal residual stresses in topology optimization of structures built by additive manufacturing,” Math. Model. Methods Appl. Sci., vol. 28, no. 12, pp. 2313–2366, 2018 doi.org/10.1142/s0218202518500501

Conference: SAMPE 2024

Publication Date: 2024/05/20

SKU: TP24-0000000104

Pages: 15

Price: $30.00