An investigation into reinforced and functionally graded lattice structures

Maskery, Ian; Hussey, Alexandra; Panesar, Ajit; Aremu, Adedeji; Tuck, Christopher; Ashcroft, Ian; Hague, Richard J.M.

Abstract

Lattice structures are regarded as excellent candidates for use in lightweight energy absorbing applications, such as crash protection. In this paper we investigate the crushing behaviour, mechanical properties and energy absorption of lattices made by an additive manufacturing (AM) process. Two types of lattice were examined; body-centred-cubic (BCC) and a reinforced variant called BCCz. The lattices were subject to compressive loads in two orthogonal directions, allowing an assessment of their mechanical anisotropy to be made. We also examined functionally graded versions of these lattices, which featured a density gradient along one direction. The graded structures exhibited distinct crushing behaviour, with a sequential collapse of cellular layers preceding full densification. For the BCCz lattice, the graded structures were able to absorb around 114% more energy per unit volume than their non-graded counterparts before full densification, 1371 +or- 9 kJ/m3 vs. 640 +or- 10 kJ/m3. This highlights the strong potential for functionally graded lattices to be used in energy absorbing applications. Finally, we determined several of the Gibson-Ashby coefficients relating the mechanical properties of lattice structures to their density; these are crucial in establishing the constitutive models required for effective lattice design. These results improve the current understanding of AM lattices, and will enable the design of sophisticated, functional, lightweight components in the future.

Citation

Maskery, I., Hussey, A., Panesar, A., Aremu, A., Tuck, C., Ashcroft, I., & Hague, R. J. (in press). An investigation into reinforced and functionally graded lattice structures. Journal of Cellular Plastics, https://doi.org/10.1177/0021955X16639035

• Journal Article Type: Article
• Acceptance Date: Jan 16, 2016
• Online Publication Date: Mar 18, 2016
• Deposit Date: Feb 25, 2016
• Publicly Available Date: Mar 18, 2016
• Journal: Journal of Cellular Plastics
• Print ISSN: 0021-955X
• Electronic ISSN: 1530-7999
• Publisher: SAGE Publications
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1177/0021955X16639035
• Keywords: selective laser sintering, additive manufacture, lattice, functional grading, energy absorption, mechanical testing
• Public URL: https://nottingham-repository.worktribe.com/output/779879
• Publisher URL: http://cel.sagepub.com/content/early/2016/03/18/0021955X16639035.abstract
• Contract Date: Feb 25, 2016