Mechanical behavior of Microlattice with or without in-plane elements added on the outer faces. (December 2018)

• Record Type: Journal Article
• Authors: Choi, Dae Han; Lee, Min Geun; Han, Seung Chul; Jeong, Yoon Chang; Cho, Jeong Shik; Kang, Kiju
• Is Part Of: International journal of mechanical sciences. Volume 149(2018)
• Page Start: 311
• Page End: 325
• Publication Date: 2018-12
• Subjects: Cellular material -- Microlattice -- Hollow truss -- Hierarchical structure -- UV lithography; Mechanical engineering -- Periodicals; Génie mécanique -- Périodiques; Mechanical engineering; Maschinenbau; Mechanik; Zeitschrift; Periodicals; 621.05
• DOI: 10.1016/j.ijmecsci.2018.10.005
• Languages: English
• ISSNs: 0020-7403

Abstract

Highlights: Microlattice is a mechanical metamaterial with ultralow density and mass productivity. Under out-of-plane compression, its strength is over-estimated due to frictional contact. We suggest a method to add in-plane truss elements on the outer faces. Under in-plane compression, the added in-plane elements show significant reinforcement. The strengths and failure modes estimated by analytic solutions agree with the test results. Abstract: Microlattice is the most advanced version of truss cellular materials with ultralow density and high mass productivity, thanks to the mask-based lithography. However, its structure lacks in-plane truss elements, which results in low structural stability. This paper investigates the effect of the structural incompleteness on its mechanical behavior of Microlattice by comparison with that of another Microlattice with in-plane truss elements added on its outer faces. The mechanical properties of the Microlattices with and without in-plane elements were evaluated through compression tests of the single-layered specimens in two different directions. Under out-of-plane compression, the in-plane elements added to the conventional Microlattice specimens did not show any effect and failed to enhance the strength and stiffness. Finite element analysis revealed that high friction at contacts caused the unexpected results. In contrast, under in-plane compression, the in-plane elements showed significant enhancement. Simple analytic solution of the compressive strength of the enhanced Microlattices under in-plane compression agreed fairly well with the experimental results, and explained well the failure mode transition. Graphical abstract: Image, graphical abstract