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Abstract This study presents an experimental investigation to examine the mixed‐mode fracture behavior of fused filament fabrication printed acrylonitrile butadiene styrene (ABS). The single‐edge notch bending specimen configuration is employed to perform mixed‐mode fracture experiments. Four distinct printing orientations—90°, 0°, 45°/−45°, and 90°—are investigated. For each orientation, fracture studies are conducted under pure mode‐I loading (symmetric three‐point bending), mixed‐mode I/II, and pure mode‐II loading (asymmetric three‐point bending) to establish a mixed‐mode fracture criterion. The study evaluates the influence of printing orientation on fracture toughness, crack propagation behavior, and the mixed‐mode fracture criterion. Scanning electron microscopy (SEM) is utilized to analyze the fracture surfaces and correlate the observed fracture mechanisms with the measured fracture toughness values. The findings reveal that printing orientation significantly affects both the fracture toughness and the mixed‐mode fracture criterion. Among the orientations studied, the 90° specimens exhibit the highest fracture toughness and superior performance under all mixed‐mode conditions. SEM images of the fracture surfaces across different printing orientations show the formation of smooth shear zones of varying sizes near the crack tip under mixed‐mode and pure mode‐II conditions. These zones suggest an enhanced resistance to crack propagation, with the degree of improvement differing among the orientations. HighlightsMixed‐mode fracture behavior of 3D‐printed acrylonitrile butadiene styrene.Printing orientations have a major influence on mixed‐mode fracture criterion.90° printing orientation has the highest fracture toughness for mode‐mixities.0° printing orientation has the lowest fracture toughness for mode‐mixities.Fracture surface has dominant shear zone for all mode‐mixities except mode‐I.
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A novel three-dimensional notch fracture criterion via effective critical distances
Many well-known fracture criteria rely on a mode-independent parameter measured under pure mode I loading conditions, called the critical distance, which is traditionally considered a material property representing the size of the fracture processing zone. Recent studies have unveiled the potential for significantly increased accuracy in fracture criteria by utilizing a mode-dependent critical distance in calculations. In response to this revelation, the concept of effective critical distance (ECD) was recently introduced and successfully examined in cracked components under in-plane and out-of-plane loading conditions, both theoretically and experimentally. In this work, for the first time, the concept of ECD is introduced for V- and U-shaped notches to form a new three-dimensional notch fracture criterion based on the maximum principal strain (MPSN). The fracture angle and the onset of fracture predicted by the proposed criterion are theoretically compared to other existing criteria, and experimentally, to the test data presented in the literature. It is shown that the developed criterion can more accurately predict the mixed-mode I/II/III fracture behavior of V- and U-notched components which accentuates the profound significance of embracing the ECD concept in constructing three-dimensional fracture criteria.
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- Award ID(s):
- 2317406
- PAR ID:
- 10493740
- Publisher / Repository:
- Elsevier
- Date Published:
- Journal Name:
- International Journal of Mechanical Sciences
- Volume:
- 271
- ISSN:
- 0020-7403
- Page Range / eLocation ID:
- 109149
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.ijmecsci.2024.109149
