Development of Meta-material with the Re-entrant Structure using 3D Printing Technology

Abstract

Auxetic materials refer to a kind of materials with a negative Poisson’s ratio (NPR). In other words, when under tension or compression load, the auxetic materials will perform transverse expansion or contraction simultaneously. This makes them superior to conventional engineering materials in fracture toughness, energy absorption, shear modulus, and indentation resistance. Such an unusual property profile also makes them promising materials for different applications, including biomedical, civil, aerospace, automotive, etc. Recently, the emerging 3D printing technology has drawn great attention to manufacturing meta-materials. Nevertheless, there is still a lack of in-depth understanding of the basic process-structure-properties relationship in printing meta-materials, which has hindered the development of these novel materials using the powerful printing technology. In particular, research on auxetic materials mostly focuses on their elastic behaviour. Little work has been done to characterize their failure behaviour or performance under large deformation. Also, the influence of printing parameters on the properties of the printed auxetic structure has not been well understood. This thesis aims to carry out a systematic study of a typical auxetic material with the re-entrant structure fabricated using 3D printing technology. The work not only explores the effects of geometry and base materials on their auxetic properties, but also investigates the role of the manufacturing parameters in determining the mechanical properties of the printed structure. Further, the new potential tribological applications of auxetic materials are also discussed.