Over the past two decades, a relatively new field known as topology optimization is rapidly expanding in computational design research. In contrast to the detailed designs (e.g. size and shape optimizations) of a structure, topology optimization [1] is highly challenging at the conceptual design stage, because it requires automatic determination of an optimal material layout of a structure in conjunction with an optimal shape of the boundary, to make cost-efficient use of a given amount of material for improving the concerned structural performance. Topology optimization can be regarded as an iterative numerical procedure to re-distribute the material in a fixed reference domain subject to boundary conditions. The optimal topology of the structure can be obtained, in association with an optimal material connectivity, when a pre-defined objective function reaches its extremity under specific constraints. Topology optimization has been applied to a broad range of existing research areas [1], and is continuously being introduced to many new and emerging areas, as an enabling persuasive design technique.Several typical methods have been developed for topology optimization of structures, including the homogenization method [2], the SIMP (Solid Isotropic Material with Penalization) approach [3,4] and the level set-based method [5][6][7][8]. Topology optimization essentially belongs to a family of integer programming problems with a large number of discrete design variables. On one hand, many wellestablished more efficient gradient-based optimization algorithms cannot be directly applied, due to the discrete nature of the problem. On the other hand, conventional discrete optimization algorithms, such as the genetic algorithms, may not be used to effectively find the solution of such large-scale discrete optimization problems, due to the "NP-Hard" difficulty. To this end, the homogenization and SIMP are two typical methods, which have been widely used to relax the original discrete optimization problem, to allow the discrete design variables taking intermediate values ranging from 0 to 1.In particular, SIMP, as an extension of the homogenization method, has received popularity in the area of structural optimization, due to its conceptual simplicity and implementation easiness. SIMP has already had several variant formulations, including elemental density based SIMP [4], nodal density based SMIP [9] and meshless field points based SIMP [10]. With SIMP, the original discrete optimization is changed to
AbstractThis paper will give a short survey about topology optimization of structures. It is particularly focused on topological shape optimization of structures using level-set methods, including the level-set based standard methods and the level-set based alternative methods. The former often directly solve the Hamilton-Jacobi partial differential equation (H-J PDE) to obtain the boundary velocity field using Finite Differential Methods (FDM), and the later commonly employ parametric or equivalent methods to evaluate the ...