PSI - Issue 12

Mattia Frascio et al. / Procedia Structural Integrity 12 (2018) 32–43 Mattia Frascio / Structural Integrity Procedia 00 (2018) 000 – 000

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Marissen (2001) Chandran -(2016) Park (2015) Caliskan(2016) Padzi (2017)

Stress amplitude, σₐ

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Number of cycles to failure, N

Fig. 7. Comparison of the S-N curves for ABS from various literature sources.

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Padzi (2017); FDM1 Padzi (2017); FDM2 Lee (2012); Flat-X Lee (2012); Flat-Y Lee (2012); Flat-45 Lee (2012); Vert-X Lee (2012); Vert-Y Lee (2012); Vert-45 Ziemian (2016); 0° Ziemian (2016); 45° Ziemian (2016); 90° Ziemian (2016); ±45°

Stress amplitude, σₐ

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Number of cycles to failure, N

Fig. 8. Comparison of the S-N curves for ABS samples made with FDM from various literature sources.

3.2. Directional fatigue behavior

Results from fatigue testing on the samples gave interesting information: the scatter was relatively contained despite the various sources of uncertainties due to the unavoidable manufacturing defects including poor surface finish (each sample was tested as is that is without surface modifications) and the typical internal defects of FDM. However, the S-N curves showed well defined and reasonable trends that will be discussed. Fig. 9 reports a comparison between the S-N curves obtained from the A samples in the two deposing orientations. From a first observation there is a clear influence of the stress-ratio. Curiously, the influence is not the same and A- samples were much more affected by the different stress-ratio, especially in the low range of endurance, mostly because the build direction with the notch faced down is critical for geometry accuracy.