Efficient generation strategy for hierarchical porous scaffolds with freeform external geometries

Abstract

The external geometry design and manipulation of internal porosity distribution according to the actual application demands are the main challenges of scaffold generation; moreover, computational efficiency is a key factor that should be considered. This paper proposes efficient generation strategies for constructing internal porous architectures by using triply periodic minimal surfaces (TPMSs) and external freeform shapes through T-spline surfaces. After discretizing the geometries as slicing contours, TPMSs can be efficiently extracted using the intersection-interpolation method in 2D space, and then be offset as infill areas of sheet solids. Based on the proposed fractal sheet TPMSs, hierarchical scaffolds are further generated using the refined constrained Delaunay triangulation method to construct multiscale pores. The porosity features can be conveniently controlled in 2D space according to the actual computed tomography images. Eventually, the resulting infill areas can be directly fabricated as scaffolds by additive manufacturing technology. Several experimental instances validate the effectiveness and efficiency of the proposed strategies.