On two-step design of microstructure with desired Poisson's ratio for AM

In this paper, a two-step optimization method is developed for designing microstructures with desired mechanical properties for 3D printing. Particularly, this method takes the numerical advantages of both material-based and boundary representation-based approaches to create microstructures with desired Poisson's ratios. The optimized microstructures possess explicit and smooth boundaries and thus they can be 3D printed without tedious post processing. In addition, the method can effectively prevent property deviations when interpreting the numerical solutions involving stepwise boundaries. Three 3D microstructures with different Poisson's ratios are numerically optimized and then fabricated using the Selective Laser Sintering technique. The practical Poisson's ratios of the samples are measured by conducting compression experiments. It will be seen that the tested Poisson's ratios match the numerical estimations in a high consistency, which demonstrates the advance of our design method for creating reliable microstructures for 3D printing and practical use.