Design, mechanical properties and optimization of lattice structures with hollow prismatic struts. (15th January 2023)

• Record Type: Journal Article
• Authors: Zhao, Miao; Li, Xinwei; Zhang, David Z.; Zhai, Wei
• Is Part Of: International journal of mechanical sciences. Volume 238(2023)
• Publication Date: 2023-01-15
• Subjects: Lattice structure -- Mechanical properties -- Topology optimization -- Additive manufacturing -- Lightweight design; Mechanical engineering -- Periodicals; Génie mécanique -- Périodiques; Mechanical engineering; Maschinenbau; Mechanik; Zeitschrift; Periodicals; 621.05
• DOI: 10.1016/j.ijmecsci.2022.107842
• Languages: English
• ISSNs: 0020-7403

Abstract

Highlights: The inner hollow size is introduced to control deformation and mechanical properties. The large inner hollow size significantly improves the elastic modulus. The elastically isotropic hollow-strut lattice structures are obtained. The optimization framework considers the volume fraction and inner hollow size. The framework improves structure's stiffness compared with traditional approaches. Abstract: Lattice structures with hollow struts exhibit superior mechanical properties as compared to solid ones. In this study, we introduce a new type of body-centered cubic (BCC) lattice, consisting of hollow prismatic struts with mechanical properties defined by an inner hollow parameter. The mechanical properties and deformation behavior of the BCC lattice structures with different inner hollow parameters are investigated under periodic boundary conditions. It is shown that the elastic modulus of the hollow-strut BCC lattice structure improves significantly by 598%-1460% and their deformation mechanism gradually changes from bending-dominated to stretching-dominated, when the inner hollow size increases. In contrast, there are little influences on shear deformation. Interestingly, tunable Poisson's ratio and isotropic elasticity can be achieved by adjusting the inner hollow size. In addition, the BCC lattice structures with different inner hollow parameters are fabricated by digital light processing for compression tests, and the experimental results are in good agreement with the simulation with relative errors of less than 14.6%. Finally, a high-fidelity interpolation model is employed to describe the effective elastic matrix of lattice structures, and a new optimization framework is proposed to simultaneously optimize the distribution of the volume fraction and inner hollow size of hollow-strut lattice structures. This proposed approach significantly improves the stiffness (compliance decreased by 15.8% to 53.1%) of the cantilever beam as compared to traditional optimal designs, demonstrating the potential application of the proposed approach in lightweight designs. Graphical abstract: Image, graphical abstract