Fracture analysis of a 3D-printed ABS specimen: Effects of raster angle and layer orientation
Understanding the mechanical response of polymer components fabricated by fused deposition modeling (FDM) is an important issue. Therefore, the present study deals with the effects of raster angle and layer orientation on the tensile properties and fracture toughness of acrylonitrile butadiene styrene (ABS) specimens produced by the FDM method. Two groups of specimens are considered. The first group includes specimens with the same layer orientation and the four different raster angles 0°/90°, 15°/-75°, 30°/-60°, and 45°/-45°. Specimens in the second group have the fixed raster angle 45°/-45° and three different layer orientations. Tensile tests are performed using dumbbell specimens, and semicircular bending (SCB) specimens were used for fracture mechanics tests. The critical value of J-integral obtained from finite element simulations is used as a parameter to characterize fracture properties. In the first group of specimens, the critical value of J-integral for the 45°/-45° specimen is 4389 J/m<sup>2</sup> while it is about 1880 J/m<sup>2</sup> for the 0°/90° specimen. In the second group, the vertically printed specimens have the least fracture resistance 1004 J/m<sup>2</sup>, while this value reaches 5934 J/m<sup>2</sup> for the specimens in which the precrack is perpendicular to the printed layers. In addition, the fracture surface of tensile specimens is analyzed using scanning electron microscopy for the mesomechanical study of failure in the printed specimens. Lastly, the crack path in SCB specimens is explored experimentally to understand how the raster angle and layer orientation affect the fracture trajectory and to justify different values of fracture loads.