You have just completed your registration at OpenAire.
Before you can login to the site, you will need to activate your account.
An e-mail will be sent to you with the proper instructions.
Important!
Please note that this site is currently undergoing Beta testing.
Any new content you create is not guaranteed to be present to the final version
of the site upon release.
Additive Manufacturing (AM) enables the production of geometrically complex parts that are difficult to manufacture by other means. However, conventional CAD systems are limited in the representation of such parts. This issue is exacerbated when lattice structures are combined or embedded within a complex geometry. This paper presents a computationally efficient, voxel-based method of generating lattices comprised of practically any cell type that can conform to an arbitrary external geometry. The method of conforming involves the tessellation and trimming of unit cells that can leave ‘hanging’ struts at the surface, which is a possible point of weakness in the structure. A method of joining these struts to form an external two dimensional lattice, termed a ‘net-skin’ is also described. Traditional methods of manufacturing lattice structures generally do not allow variation of cell properties within a structure; however, additive manufacturing enables graded lattices to be generated that are potentially more optimal. A method of functionally grading lattices is, therefore, also described to take advantage of this manufacturing capability.
[1] M.P. Bendsoe, sigmund, O, in: Topological Optimization: Theory, Methods and Applications, Springer-Verlag, Berlin, 2004, p. 370.
[2] M. Abdi, R. Wildman, I. Ashcroft, Evolutionary topology optimization using the extended finite element method and isolines, Eng. Optim. (2013), http:// dx.doi.org/10.1080/0305215x.2013.791815.
[3] X. Huang, Y. Xie, Convergent and Mesh-independent Solutions for the Bi-directional Evolutionary Structural Optimization Method Finite Elements in Analysis and Design, 43, 2007, pp. 1039-1049.
[4] G.I.N. Rozvany, M. Zhou, T. Birker, Generalized shape optimization without homogenization Structural Optimization, 4, 1992, pp. 250-252.
[5] M.Y. Wang, X. Wang, D. Guo, A level set for method for structural topology optimization Computer Methods in Applied Mechanics and Engineering, 192, 2003, pp. 227-246.
[6] D. Brackett, I. Ashcroft, R. Hague, Topology Optimization for Additive Manufacture, 21st Solid Freeform Fabrication Symposium, 2011, p. 12.
[7] A. Aremu, I. Ashcroft, R. Wildman, R. Hague, C. Tuck, D. Brackett, The effects of bidirectional evolutionary structural optimisation parameters on an industrial designed component for additive manufacture, Proc. Inst. Mech. Eng., Part B: J. Eng. Manuf. 227 (6) (2013) 794-807, http://dx.doi.org/10.1177/ 0954405412463857.
[8] B.M. Wood, Introduction to additive manufacturing Design and Manufacture of Plastic Components for Multifunctionality, 00005-3, 2016, pp. 171-204, http://dx.doi.org/10.1016/B978-0-323-34061-8.
[9] J.A. Madeira, H.C. Rodrigues, H. Pina, Multiobjective topology optimization of structures using genetic algorithms with chromosome repairing, Struct. Multidiscipl. Optim. (2006), http://dx.doi.org/10.1007/s00158-006-0007-0.
[10] J.A. Madeira, H.C. Rodrigues, H. Pina, Multi-objective optimization of structures topology by genetic algorithms, Adv. Eng. Softw. 36 (2005) 21-28.
[11] W. Gao, Y. Zhang, D. Ramanujan, K. Ramani, Y. Chen, C.B. Williams, C.C.L. Wang, Y.C. Shin, S. Zhang, The status, challenges, and future of additive manufacturing in engineering, Comput.-Aided Des. 69 (2015) 65-89.
[12] M.F. Ashby, The properties of foams and lattices, Phil. Trans. R. Soc. A 364 (2006) 15-30, http://dx.doi.org/10.1098/rsta.2005.1678.
[13] X. Huang, S. Zhou, Y.M. Xie, Topology Optimization of microstructures of cellular materials and composites for macrostructures, Comput. Mater. Sci. 67 (2013) 397-407.
[14] X. Huang, A. Radman, Y. Xie, Topological design of microstructures of cellular materials for maximum bulk or shear modulus, Comput. Mater. Sci. 50 (2011) 1861-1870.
[15] L.J. Gibson, M.F. Ashby, Cellular Solids: Structure and Properties, Cambridge University Press, 1997.
[16] D.A. Ramirez, L.E. Murr, S.J. Li, Y.X. Tian, E. Martinez, J.L. Martinez, B.I. Machado, S.M. Gaytan, F. Medina, R.B. Wicker, Open-cellular copper structures fabricated by additive manufacturing using electron beam melting, Mater. Sci. Eng. A 528 (2011) 5379-5386.
[17] C. Yan, L. Hao, A. Hussein, D. Raymont, Evaluations of cellular lattice structures, manufactured using selective laser melting, Int. J. Mach. Tools Manuf. (2012) 32-38.
[19] M. Smith, Z. Guan, W.J. Cantwell, Finite element modelling of the compressive response of lattice structures manufactured using the selective laser melting technique, Int. J. Mech. Sci. 28-41 (2013) 67.
[20] C. Yan, L. Hao, A. Hussein, P. Young, J. Huang, W. Zhu, Microstructure and mechanical properties of aluminium alloy cellular lattice structures manufactured by direct metal laser sintering, Mater. Sci. Eng. A 628 (2015) 238-246.
[21] L. Mullen, R.C. Stamp, W.K. Brooks, E. Jones, C.J. Sutcliffe, Selective laser melting: a regular unit cell approach for the manufacture of porous, titanium, bone in-growth constructs, suitable for orthopaedic applications, J. Biomed. Mater. Res. B Appl. Biomater. 89B (2009) 325-334, http://dx.doi.org/10.1002/ jbm.b.31219.
[22] S. Mckwon, Y. Shen, W.K. Brookes, C.J. Sutcliffe, W.J. Cantwell, G.S. Langdon, G.N. Nurick, M.D. Theobald, The quasi-static and blast loading response of lattice structures, Int. J. Impact Eng. 35 (2008) 795-810.
[23] M. Vesenjak, L. Krstulovic-Opara, Z. Ren, Z. Domazet, Cell shape effect evaluation of polyamide cellular structures, Polym. Test. 29 (2010) 991-994.
[24] A. Hussein, L. Hao, C. Yan, R. Everson, P. Young, Advanced lattice support structures for metal additive manufacturing, J. Mater. Process. Technol. 213 (2013) 1019-1026.
[25] N. Guo, C. Leu, Additive manufacturing: technology, applications and research needs, Front, Mech. Eng. 8 (3) (2013) 215-243.
[27] D.E. LaCourse, Handbook of Solid Modelling, McGraw-Hill, 1995, 2016.
[28] M.M.M. Sarcar, K.M. Rao, L. Narayan, Computer Aided Design and Manufacturing, PHI Learning Pvt, 2008, p.728.
[29] I. Stroud, H. Nagy, Solid Modelling and CAD Systems: How to Survive a CAD System, Springer Science & Business Media, 2011, p.689.
[30] M.W. Jones, J.A. Baerentzen, M. Sramek, 3D distance fields: a survey of techniques and applications, IEEE Trans. Vis. Comput. Graphics 12 (4) (2006) 581-599.
[32] A. Kaufman, An algorithm for 3D scan-conversion of polygons, in: Eurographics'87, Elsevier Science Publishers, 1987.
[33] Chen Y. Wang, Regulating complex geometries using layered depth-normal images for rapid prototyping and manufacturing, Rapid Prototyp. J. 17 (4) (2013) 253-268.
[34] H. Wang, Y. Chen, D.W. Rosen, A Hybrid Geometric modelling method for large scale conformal cellular structures, 25th Computers and Information in Engineering Conference, Parts A and B vol. 3 (2005) 421-427.
[35] C. Chu, G. Graf, D.W. Rosen, Design for additive manufacturing of cellular structures, Comput.-Aided Des. Appl. 5 (5) (2008) 686-696.
[36] D.W. Rosen, Computer-aided design for additive manufacturing of cellular structures, Comput.-Aided Des. Appl. 4 (5) (2007) 585-594.
[37] G.E. Farin, Curves and Surfaces for CAGD: a Practical Guide, 5th ed., Academic Press, 2002.
[38] J. Fish, T. Belytschko, A First Course in Finite Elements, John Wiley & Sons, 2007.
[40] J. Nguyen, S. Park, D.W. Rosen, L. Folgar, J. Williams, Conformal lattice structure design and fabrication, 22nd Solid Freeform Fabrication Symposium (2012) (p. 24).
[41] A. Karabassi, G. Papaioannou, T. Theoharis, A depth duffer based voxelization algorithm, J. Graphics Tools 4 (4) (1999) 5-10.
[42] S. Fang, H. Chen, Hardware accelerated voxelization, in: Volume Graphics, 2000, pp. 301-315.
[43] S. Thon, G. Gesquiere, R. Raffin, A Low Cost Anatialiased Space Filled Voxelization of Polygonal Objects, International Conference Graphion, 2004.
[44] V. Chandru, S. Manohar, Voxel-based modelling for layered manufacturing, IEEE Comp. Graphics 15 (no. 6) (1995) 42-47.
[45] A.E. Kaufman, Volume visualization of the ascending thoracic aorta using isotropic MDCT data: protocol optimization, ACM Comput. Surv. (CSUR) 28 (no. 1) (1996) 165-167.
[46] I.M. Pitas, Digital Image Processing Algorithms and Applications, John Wiley & Sons, New York, 2000 (p. 419).
[47] A.O. Aremu, I. Maskery, C.T. Tuck, I.A. Ashcroft, R. Wildman, R. Hague, Effects of net and solid skins on self-Supporting lattice structures, Challenges in Mechanics of Time Dependent Materials, Volume 2: Proceedings of the 2015 Annual Conference on Experimental and Applied Mechanics (2015) (p. 104).
[48] R.C. Gonzalez, R.E. Woods, S.L. Eddins, Digital Image Processing Using MATLAB, Pearson Prentice Hall, New Jersey, 2004.
[49] Common Layer Interface (CLI): Version 2.0 Specification.