Interface study and boundary smoothing on designed composite material microstructures for manufacturing purposes

The manufacturability of composite material microstructures designed by the homogenized topology optimization method has to be considered when bringing the design into reality. In this paper, numerical studies are conducted on multiphase material microstructures that have negative coefficients of thermal expansion, for the purpose of improving manufacturability. Realistic manufacturing factors are considered, including the diffusion interface between two constituent phases and vectorized toolpath design. The effect of the mixture interface between two solid phases is examined by homogenization analysis. An image-processing program is developed to smooth out the boundaries of the topological structure to facilitate toolpath design. Numerical results show that the diffusion interface between two solid material phases reduces the effective negative thermal expansion property of the whole microstructure. The designedmaterial properties are retained and converge after boundary smoothing.