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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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Specimen plane orientation determination for analysis based on scanning electron microscope: Comparing top‐down and side‐view approaches
Abstract Many attachments to a scanning electron microscope (SEM), such as energy dispersive x‐ray spectroscopy, extend its function significantly. Typically, the application of such attachments requires that the specimen has a planar surface at a specific orientation. It is a challenge to make the plane of a microscale specimen satisfy the orientation requirement since they are visible only in an SEM. An in‐situ procedure is needed to adjust specimen orientation by using stage rotation and tilting functions, in the process of which the key is to determine the initial orientation. This study proposed and tested top‐down and side‐view approaches to determine the orientation of a planar surface inside an SEM. In the top‐down one, the projected area is monitored on SEM images as stage rotation and tilt angles are adjusted. When the surface normal is along the electron beam direction, the area has a maximum value. In the side‐view approach, the stage is adjusted so that the projection appears to be a straight horizontal line on the SEM image. Once the orientation of the specimen for top‐down or side‐view observation is determined, the original can be calculated, and a desired orientation can be realized by manipulating the stage. The procedures have been tested by analyzing planar surfaces of spherical particles in Al‐Cu‐Fe alloy in the form of facets. The measured angles between two surfaces are consistent with those expected from crystallographic consideration within 2.7° and 1.7° for the top‐down and side‐view approaches, respectively. Research HighlightsTop‐down and side‐view approaches have been proposed and tested for in‐situ determination of specimen planar surface orientation in a Scanning Electron Microscope.The measured angles between two surfaces are consistent with those expected from crystallographic consideration within 2.7° and 1.7° for the top‐down and side‐view approaches, respectively.
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- Award ID(s):
- 1900077
- PAR ID:
- 10446976
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Microscopy Research and Technique
- Volume:
- 86
- Issue:
- 12
- ISSN:
- 1059-910X
- Format(s):
- Medium: X Size: p. 1681-1690
- Size(s):
- p. 1681-1690
- Sponsoring Org:
- National Science Foundation
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