Topology optimization of anisotropic magnetic composites in actuators using homogenization design method

This work presents topology optimization of anisotropic magnetic composites in actuators. The magnetic composite consists of two different ferromagnetic materials with high and low magnetic reluctivity, which correspond to matrix and fiber materials, respectively. The magnetic composite is expected to enhance the actuator performance when it is properly designed. The proposed design optimization scheme can find the composite layout, fiber volume fraction, and fiber orientations to achieve an actuator force maximization. In the proposed scheme, four microstructure design variables are assigned at each finite element, and the effective homogenized material property (i.e., magnetic reluctivity) is calculated using the asymptotic homogenization method. The microstructure design variables are then optimized to achieve the optimal distribution of the homogenized material property in a macroscopic scale. In the design result, discrete fiber orientations and volume fractions are achieved by applying the discrete penalization scheme. In addition, the obtained composite design result is visualized using the projection method proposed for a periodic composite design result. The effectiveness of the proposed topology optimization procedures is validated in magnetic actuator design examples. In addition, the design result of anisotropic composite is compared with the isotropic multi-material design result to validate the benefit of anisotropic composite in actuators.