On Including Manufacturing Constraints in the Topology Optimization of Surface-Micromachined Structures
نویسندگان
چکیده
Topology optimization of structures sometimes gives designs that cannot be economically manufactured without postprocessing. Because post-processing of topology solutions might lead to suboptimal designs, it is useful to include manufacturing constraints at the outset. In this work, we present a method for the topology optimization of micromachined devices by including surface micromachining constraints. Instead of explicitly including manufacturing constraints, we propose a novel design parameterization that implicitly restricts the design space so that it consists of only the manufacturable designs for a chosen surface-micromachining foundry process. In surface-micromachining, the photolithographic masks determine the geometry of surface-micromachined structures. Therefore, we use the masks themselves as the design variables in topology optimization. By using the continuous mask opacities as the design variables, we developed a virtual material movement model (VMMM) in which the material from a layer deposited on top of a putatively porous layer will move down. Consequently, the virtual density of material in the design domain changes depending on the opacity values of the masks in different cells. This virtual density is similar to the fictitious density assumed in Simple Isotropic Material with Penalty (SIMP) and other material interpolation techniques. The difference is that the opacity values of the masks are design variables here whereas the densities of the cells themselves are design variables in SIMP. In this manner, surface-micromachining constraints are implicitly satisfied in this design parameterization. An optimality criteria method aided by sensitivity analysis is implemented in Comsol MultiPhysics platform. Micromachined foundry processes such as MUMPs and SUMMiT are considered in the examples presented to demonstrate the efficacy of the method. An added benefit of the new method is that lithography mask layouts are readily generated in addition to manufacturable optimal topologies. Several examples are solved and discussed to show how the optimal manufacturable solutions compare with non-manufacturable ones.
منابع مشابه
ISOGEOMETRIC TOPOLOGY OPTIMIZATION OF STRUCTURES CONSIDERING WEIGHT MINIMIZATION AND LOCAL STRESS CONSTRAINTS
The Isogeometric Analysis (IA) is utilized for structural topology optimization considering minimization of weight and local stress constraints. For this purpose, material density of the structure is assumed as a continuous function throughout the design domain and approximated using the Non-Uniform Rational B-Spline (NURBS) basis functions. Control points of the density surface are...
متن کاملA NEW HYBRID ALGORITHM FOR TOPOLOGY OPTIMIZATION OF DOUBLE LAYER GRIGS
In this paper, for topology optimization of double layer grids, an efficient optimization method is presented by combination of Imperialist Competitive Algorithm (ICA) and Gravitational Search Algorithm (GSA) which is called ICA-GSA method. The present hybrid method is based on ICA but the moving of countries toward their relevant imperialist is done using the la...
متن کاملVOLUME MINIMIZATION WITH DISPLACEMENT CONSTRAINTS IN TOPOLOGY OPTIMIZATION OF CONTINUUM STRUCTURES
In this paper, a displacement-constrained volume-minimizing topology optimization model is present for two-dimensional continuum problems. The new model is a generalization of the displacement-constrained volume-minimizing model developed by Yi and Sui [1] in which the displacement is constrained in the loading point. In the original model the displacement constraint was formulated as an equali...
متن کاملTOPOLOGY OPTIMIZATION OF PRETENSIONED CONCRETE BEAMS CONSIDERING MATERIAL NONLINEARITY
In this paper, the bi-directional evolutionary structural optimization (BESO) method is used to find optimal layouts of 3D prestressed concrete beams. Considering the element sensitivity number as the design variable, the mathematical formulation of topology optimization is developed based on the ABAQUS finite element software package. The surface-to-surface contact with a small sliding between...
متن کاملAutomotive Wheel Optimization to Enhance the Fatigue Life
Nowadays, lightweight automotive component design, regarding fuel consumption, environmental pollutants and manufacturing costs, is one of the main issues in the automotive societies. In addition, considering safety reasons, the durability of the automotive components, as one of the most important design requirements should be guaranteed. In this paper, a two-step optimization process including...
متن کامل