Manufacturing Issues and the Resulting Complexity in Modeling of Additively Manufactured Metallic Microlattices

Abstract:

Although metallic microlattice material is a sought after research topic currently, it suffers from manufacturing defects such as micro-voids formation due to missed fusion, stemmed from the stacking-layered-fused nature of the metal powder in Powder Bed Fusion (PBF) process. These defects result in weakening of the finished part and reduced mechanical performance under service load, possibly leading to low fatigue strength, and raise serious question about 3D printed structural integrity. Numerical simulation of the built parts also becomes difficult due to irregular physical properties including geometry and anisotropic nature of mechanical properties. This paper provides an overview on the manufacturing issues and the subsequent hurdle faced in numerical simulation of metallic microlattices. While the issues in manufacturing are related to emerging additive manufacturing techniques and out of control of end users, it has been suggested that the limitations in numerical simulation can be overcome by employing advanced approaches, in both physical properties measurement and modeling.

• Periodical: Applied Mechanics and Materials (Volume 853)
• Pages: 394-398
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.853.394
• Online since: September 2016
• Authors: M.G. Rashed, Mahmud Ashraf*, Paul Jonathan Hazell
• Keywords: 3D Printed Structural Integrity, Metallic Microlattices, Numerical Simulation

References

[1] M.G. Rashed, M. Ashraf, R.A.W. Mines, P.J. Hazell, Metallic microlattice materials: A current state of the art on manufacturing, mechanical properties and applications, Mater. Des. 95 (2016) 518–533. doi: 10. 1016/j. matdes. 2016. 01. 146.

DOI: 10.1016/j.matdes.2016.01.146

[2] R.A.W. Mines, On the characterisation of foam and micro-lattice materials used in sandwich construction, Strain. 44 (2008) 71–83. doi: 10. 1111/j. 1475-1305. 2008. 00399. x.

DOI: 10.1111/j.1475-1305.2008.00399.x

[3] O. Rehme, Cellular design for laser freeform fabrication, Cuvillier, (2010).

[4] S.K. Everton, M. Hirsch, P. Stravroulakis, R.K. Leach, A.T. C lare, Review of in-situ process monitoring and in-situ metrology for metal additive manufacturing, Mater. Des. (2016). doi: 10. 1016/j. matdes. 2016. 01. 099.

DOI: 10.1016/j.matdes.2016.01.099

[5] Advances in production technology, Springer International Publishing, 2015. http: /link. springer. com/chapter/10. 1007/978-3-319-12304-2.

[6] D.D. Arola, M.L. McCain, Abrasive waterjet peening: A new method of surface preparation for metal orthopedic implants, J. Biomed. Mater. Res. 53 (2000) 536–546. doi: 10. 1002/1097-4636(200009)53: 5<536: AID-JBM13>3. 0. CO; 2-V.

DOI: 10.1002/1097-4636(200009)53:5<536::aid-jbm13>3.0.co;2-v

[7] R. Gümrük, R.A.W. Mines, Compressive behaviour of stainless steel micro-lattice structures, Int. J. Mech. Sci. 68 (2013) 125–139. doi: 10. 1016/j. ijmecsci. 2013. 01. 006.

DOI: 10.1016/j.ijmecsci.2013.01.006

[8] C.C. Seepersad, J.K. Allen, D.L. McDowell, F. Mistree, Robust design of cellular materials with topological and dimensional imperfections, J. Mech. Des. 128 (2006) 1285–1297. doi: 10. 1115/1. 2338575.

DOI: 10.1115/1.2338575

[9] C. Qiu, S. Yue, N.J.E. Adkins, M. Ward, H. Hassanin, P.D. Lee, et al., Influence of processing conditions on strut structure and compressive properties of cellular lattice structures fabricated by selective laser melting, Mater. Sci. Eng. A. 628 (2015).

DOI: 10.1016/j.msea.2015.04.074

[10] P. Mercelis, J. Kruth, Residual stresses in selective laser sintering and selective laser melting, Rapid Prototyp. J. 12 (2006) 254–265. doi: 10. 1108/13552540610707013.

DOI: 10.1108/13552540610707013

[11] O. Cansizoglu, O.L.A. Harrysson, H.A. West, D.R. Cormier, T. Mahale, Applications of structural optimization in direct metal fabrication, Rapid Prototyp. J. 14 (2008) 114–122. doi: 10. 1108/13552540810862082.

DOI: 10.1108/13552540810862082

[12] P. Li, Constitutive and failure behaviour in selective laser melted stainless steel for microlattice structures, Mater. Sci. Eng. A. 622 (2015) 114–120. doi: 10. 1016/j. msea. 2014. 11. 028.

DOI: 10.1016/j.msea.2014.11.028

[13] G. Pyka, A. Burakowski, G. Kerckhofs, M. Moesen, S. Van Bael, J. Schrooten, et al., Surface modification of Ti6Al4V open porous structures produced by additive manufacturing, Adv. Eng. Mater. 14 (2012) 363–370. doi: 10. 1002/adem. 201100344.

DOI: 10.1002/adem.201100344

[14] Standard specification for additive manufacturing titanium-6 aluminum-4 vanadium with powder bed fusion, ASTM International, West Conshohocken, PA, 2014. www. astm. org.

DOI: 10.1520/f2924-12

[15] M.G. Rashed, M. Ashraf, P.J. Hazell, Evaluation of rate-dependent plasticity models in numerical simulation of metallic light-weight microlattice materials, in: Proc. Eighth Int. Conf. Adv. STEEL Struct., University of Lisbon, Lisbon, Portugal, (2015).

[16] M. Smith, The compressive response of novel lattice structures subjected to static and dynamic loading, PhD thesis, University of Liverpool, (2012).

[17] S. Lee, F. Barthelat, J.W. Hutchinson, H.D. Espinosa, Dynamic failure of metallic pyramidal truss core materials – Experiments and modeling, Int. J. Plast. 22 (2006) 2118–2145. doi: 10. 1016/j. ijplas. 2006. 02. 006.

DOI: 10.1016/j.ijplas.2006.02.006

[18] A. Ramasubramaniam, E.A. Carter, Coupled quantum–atomistic and quantum–continuum mechanics methods in materials research, MRS Bull. 32 (2007) 913–918. doi: 10. 1557/mrs2007. 188.

DOI: 10.1557/mrs2007.188

[19] L. Valdevit, S.W. Godfrey, T.A. Schaedler, A.J. Jacobsen, W.B. Carter, Compressive strength of hollow microlattices: Experimental characterization, modeling, and optimal design, J. Mater. Res. 28 (2013) 2461–2473. doi: 10. 1557/jmr. 2013. 160.

DOI: 10.1557/jmr.2013.160