A 3D bi-material lattice concept for tailoring compressive properties. (December 2022)

• Record Type: Journal Article
• Authors: Ruschel, Amanda L.; Samuel, Avery F.; Martinez, Marco Colin; Begley, Matthew R.; Zok, Frank W.
• Is Part Of: Materials & design. Volume 224(2022)
• Publication Date: 2022-12
• Subjects: Lattice design -- 3D printing -- Multi-material -- Tailoring mechanical properties; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2022.111265
• Languages: English
• ISSNs: 0264-1275

Abstract

Graphical abstract: Highlights: A novel concept in bi-material lattice design enables tailoring of compressive response. Designs employing hinged knob-and-socket joints facilitate strut rotations and unconstrained articulation. A variety of lattice geometries can be employed, employing straight struts, curved struts and flat sheets. Bi-material lattices can exploit emergent multi-material printing capabilities and open up new design space. Abstract: The current article explores 3D bi-material lattice concepts for tailoring compressive stress-strain response. The unit cells of the lattices consist of six stiff inclined struts that together form the edges of two stacked tetrahedra. The central plane (between the two tetrahedra) contains elastomeric elements that stretch when the lattice is compressed. The geometric configurations of the elastomers examined here include: (i) straight struts between each node pair within the central plane, (ii) multiple struts between each node pair, including one straight strut and one or more curved struts, and (iii) flat sheets, either uniform or graded in thickness, connected at the mid-plane nodes. Assessments of the concepts are made using analytical models, finite element simulations, and experiments on lattices fabricated by 3D printing. The experimental results affirm the understanding of mechanical response gleaned from the models and highlight the importance of joint design in attaining large straining capacity and strain reversibility. They also demonstrate a nearly twofold increase in load bearing capacity when straight struts are replaced by graded sheets. The work also raises the prospects for computational design optimization for maximum efficiency in material use.