摘要：With the development of three-dimensional printing technologies, so-called “designer materials” including re-entrant, chiral, and rotating rigid structures have attracted much attention due to unusual properties. However, most studies ignore theoretical analysis and pay much attention to numerical simulation. In this article, a novel re-entrant cellular material is proposed and taken as an example to introduce the methods of theoretical study on relations between mechanical properties and geometric parameters of this “designer material.” This work starts from developing theoretical models of relative density using two-dimensional unit cell in terms of three geometric parameters: edge length, re-entrant distance, and cellular thickness. Then, linear-elastic mechanical properties including elastic modulus and shear modulus, and nonlinear mechanical properties are explored. Based on theoretical models, predominant compression failure mode of this material is plastic collapse. Finite element method is adopted to identify accuracy of static mechanical models. On this basis, dynamic mechanical model is put forward, the relationship of dynamic plateau stress and impact velocity, and structural parameters are established by empirical formula. Moreover, the relationship of unit volume energy absorption and geometric features, impact velocity are also established. Eventually, finite element method is utilized to prove that simulation results show a well coincidence to theoretical results.
关键词：Re-entrant cellular material; geometric features; mechanical properties; theoretical model; unit volume energy absorption
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