Level Set-Based Topology Optimization Method for Thermal Problems Considering Design-Dependent Boundary Effects

Author(s):  
Takayuki Yamada ◽  
Shinji Nishiwaki ◽  
Atsuro Iga ◽  
Kazuhiro Izui ◽  
Masataka Yoshimura

This paper proposes a new level set-based topology optimization method for thermal problems that deal with generic heat transfer boundaries including design-dependent boundary conditions, based on the level set method and the concept of the phase field theory. First, a topology optimization method using a level set model incorporating a fictitious interface energy derived from the concept of the phase field theory is briefly discussed. Next, a generic optimization problem for thermal problems is formulated based on the concept of total potential energy. An optimization algorithm that uses the Finite Element Method when solving the equilibrium equation and updating the level set function is then constructed. Finally, several three-dimensional numerical examples are provided to confirm the utility and validity of the proposed topology optimization method.

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Takayuki Yamada ◽  
Kazuhiro Izui ◽  
Shinji Nishiwaki

This paper proposes an optimum design method, based on our level set-based topology optimization method, for maximizing thermal diffusivity in problems dealing with generic heat transfer boundaries that include design-dependent boundary conditions. First, a topology optimization method using a level set model incorporating a fictitious interface energy for regularizing the topology optimization is briefly discussed. Next, an optimization method for maximizing thermal diffusivity is formulated based on the concept of total potential energy. An optimization algorithm that uses the finite element method when solving the equilibrium equation and updating the level set function is then constructed. Finally, several numerical examples are provided to confirm the utility and validity of the proposed topology optimization method.


Author(s):  
Takayuki Yamada ◽  
Toshiro Matsumoto ◽  
Shinji Nishiwaki

This paper presents an optimum design method for mechanical structures considering harmonic loads using a level set-based topology optimization method and the Finite Element Method (FEM). First, we briefly discuss the level set-based topology optimization method. Second, a topology optimization problem is formulated for a dynamic elastic design problem using level set boundary expressions. The objective functional is set to minimize the displacement at specific boundaries. Based on this formulation, the topological sensitivities of the objective functional are derived. Next, a topology optimization algorithm is proposed that uses the FEM to solve the equilibrium and adjoint equations, and when updating the level set function. Finally, several numerical examples are provided to confirm the validity and utility of the proposed method.


Author(s):  
Shintaro Yamasaki ◽  
Atsushi Kawamoto ◽  
Akira Saito ◽  
Masakatsu Kuroishi ◽  
Kikuo Fujita

In this paper, we propose a level-set based topology optimization method for designing a reactor, which is used as a part of the DC-DC converter in electric and hybrid vehicles. Since it realizes a high-power driving motor and its performance relies on its component, i.e., reactor core, it is valuable to establish a reasonable design method for the reactor core. Boundary tracking type level-set topology optimization is suitable for this purpose, because the shape and topology of the target structure is clearly represented by the zero boundary of the level-set function, and the state variables are accurately computed using the zero boundary tracking mesh. We formulate the design problem on the basis of electromagnetics, and derive the design sensitivities. The derived sensitivities are linked with boundary tracking type level-set topology optimization, and as a result, a useful structural optimization method for the reactor core design problem is developed.


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