Topology optimzation using lattice materials with isotrophy condition

Lattice materials have a lot of advantage such as lightness, stiffness, vibration damping and heat insulation. Nowadays using of lattice materials have begun to become widespread at many different areas since the designs which is generated by lattice materials can be manufactured with improving of the additive manufacturing technologies. When the design is performed by lattice materials proper densities of lattice cells in a part is determined by doing density mapping with homogenization-based topology optimization. However, mechanical behaviors of most of the lattice materials which change by direction as with composite materials are not isotropic. For Solid Isotropic Material with Penalization-SIMP method, which is used commonly in topology optimization for density mapping in commercial software due to its simplicity, some problems appear in use of lattice materials, since homogenize properties, which are not isotropic, generate different stress and displacement in different direction. The method of isotropy conditional density mapping (ICDM) is proposed to solve the problem within the scope of this thesis. Lattice cells, which are modeled by strut elements that ensure isotropy condition of homogenize elastic properties at whole density values, are determined with this proposed model. Since these lattice cells ensure isotropy condition, SIMP method can be used in topology optimization. The density range, which can be used in topology optimization, is determined to be produced with additive manufacturing. With the aim of showing effectiveness of proposed method, applications are practiced on three-dimensional different numerical example which have been designed to produce for additive manufacturing in literature. In this study, ABAQUS software is used on the stage of generating finite elements models, for obtaining the homogenize material properties and processing topology optimization. When the surface and solid model of lattice designs are generated MATLAB programme is utilized. The results of optimize design which is generated by ICDM model are compared with the results in the literature to demonstrate its superiority and verify. When the lattice configurations, which ensure isotropy condition, are determined with this proposed method macroscopic distributions of lattice cells can be obtainable with topology optimization with SIMP method available in commercial software which is showed at the same time. Keywords: Lattice materials, Homogenization, Isotropy, Topology optimization, Additive manufacturing.