Analysis Of Notch Effect Research Articles

Analysis of notch effect in the fracture behaviour of additively manufactured PLA and graphene reinforced PLA

The fracture assessment of additively manufactured PLA and graphene reinforced PLA (PLA-GR) has been performed in this paper. Tensile and fracture specimens were fabricated with three different raster orientations (0/90, 30/−60 and 45/−45) in order to analyse the effect of the printing strategy on the resulting mechanical properties. A total of 30 tensile tests and 120 fracture tests were performed, covering fracture samples with defects of different notch radii (0 mm, 0.25 mm, 0.5 mm, 1 mm and 2 mm). The Theory of Critical Distances was applied over the fracture results, obtaining estimations of the corresponding critical distances and the subsequent predictions of the apparent fracture toughness. Graphene addition has a different effect depending on the raster orientation. Graphene causes a significant improvement of tensile and fracture properties for specimens fabricated at 30/−60 and 45/−45. However, this phenomenon is not observed in raster orientation 0/90. SEM analysis shows a clear change in the fracture micromechanisms between PLA and PLA-GR. It can be also observed how graphene samples of 30/−60 and 45/−45 present a similar aspect of the fracture surfaces, which are different from those observed in raster orientation 0/90.

Numerical Analysis of Notch Effect on Fatigue Behavior of Short Fiber Reinforced Plastics Using Multi-Scale Material Modeling

Numerical Analysis of Notch Effect on Fatigue Behavior of Short Fiber Reinforced Plastics Using Multi-Scale Material Modeling

Analysis of Notch Effect in 3D-Printed ABS Fracture Specimens Containing U-Notches.

In this paper a fracture assessment in additive manufactured acrylonitrile butadiene styrene (ABS) fracture specimens containing U-notches is performed. We performed 33 fracture tests and 9 tensile tests, combining five different notch radii (0 mm, 0.25 mm, 0.50 mm, 1 mm and 2 mm) and three different raster orientations: 0/90, 30/−60 and 45/−45. The theory of critical distances (TCD) was then used in the analysis of fracture test results, obtaining additional validation of this theoretical framework. Different versions of TCD provided suitable results contrasting with the experimental tests performed. Moreover, the fracture mechanisms were evaluated using scanning electron microscopy in order to establish relationships with the behaviour observed. It was demonstrated that 3D-printed ABS material presents a clear notch effect, and also that the TCD, through both the point method and the line method, captured the physics of the notch effect in 3D-printed ABS. Finally, it was observed that the change in the fracture mechanisms when introducing a finite notch radius was limited to a narrow band behind the original defect, which appeared in cracked specimens but not in notched specimens.

Analysis of notch effect in PMMA using the Theory of Critical Distances

The Theory of Critical Distances is actually a group of methodologies, all of them using a characteristic material length parameter when performing fracture assessments on any kind of stress risers. In this paper, the application of the Theory of Critical Distances on Polymethyl methacrylate is analysed, the parameters involved in the analysis are calibrated, and the different versions of this theory are applied, with satisfactory results, to the prediction of the notch effect on the apparent fracture toughness measured on notched specimens. Also, a Scanning Electron Microscopy analysis is performed, establishing relations between the fracture mechanisms and the predictions provided by the Theory of Critical Distances.