Fracture Behavior of Additively Manufactured Topology-Graded Orthotropic Cellular ABS: Experiments and Effective-Continuum Modeling

Abstract

In this study, a combination of experiments and an effective continuum modeling approach was employed to investigate the fracture initiation and crack paths in additively manufactured ABS cellular structures. With the use of single edge–cracked tensile specimens, the effects of raster angle (printing direction), graded void size, and crack placement relative to the void arrays were systematically studied. Experiments were conducted on several 3D-printed ABS samples, and their fracture responses were analyzed under tensile loading. To obtain a spatial map of the elasticity tensor, the modeling component of this study employs a MATLAB-based numerical homogenization method (periodic unit cell approach) that accounts for 2D orthotropic material behavior. The homogenized properties are then assigned to a 2D finite element model to compute crack-driving measures at the experimental failure loads. It is shown that the crack initiation angle is mainly controlled by material orthotropy (raster direction). While cracks initiate along the printing direction, crack deflection and blunting are dictated by the void arrangement and the crack-void alignment. Moreover, this study reveals that the homogenization step provides an acceptable first-order approximation of the spatially graded orthotropic mechanical properties across the discrete domain.