PSI - Issue 34

D. Rigon et al. / Procedia Structural Integrity 34 (2021) 199–204

204

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Rigon D. et al. / Structural Integrity Procedia 00 (2021) 000–000

vPPMF-GF IM

rPPMF-GF IM

rPPMF-GF AM F0°

rPPMF-GF AM F90°

rPPMF-GF AM F±45°

R= -1 R= 0.05

2 mm

1 mm

1 mm

2 mm

2 mm

1 mm

2 mm

2 mm

1 mm

2 mm

Fig. 4. One exemplary of fracture path per each material and process technology combination.

4. Conclusions Fully reversed (R= -1) and pulsating (R= 0.05) fatigue tests have been carried out on specimens made of a recycled short-glass-fiber-reinforced and mineral-filled polypropylene produced by injection moulding (IM) and pellet additive manufacturing (AM). The effect of the recycling on the fatigue strength of the material was studied only on IM specimens, by testing the material with virgin and 100% recycled polymer matrix. The results highlighted that the recycled IM specimens have approximately 30% lower fatigue strength than those with the virgin matrix for both load ratios. All recycled AM specimens manufactured in the “flat” position on the base plate and with three different infill patterns were characterised by lower fatigue strength compared to the recycled material produced by IM and exhibited a strong anisotropy related to the infill pattern. Notably, the highest fatigue strength was observed in AM sample with deposition path parallel to the load direction, while the lowest has been found in the samples with deposition paths normal to the load direction. Finally, infill patterns with filaments oriented at ±45° showed intermediate fatigue strength. Macroscopic damage analyses did not highlight differences between the fracture paths of virgin and recycled specimens produced by IM. Regarding the AM samples, different fractures paths were found among the infill patterns in which the main macroscopic damage mechanisms were characterised by interlayer delamination and debonding of adjacent filaments. References Abdelhaleem MM. A, Megahed M, Saber D, (2018) Fatigue behaviour of pure polypropylene and recycled polypropylene reinforced with short glass fiber. Journal of Composite Materials, Vol. 52(12).16331640 Carneiro O. S, Silva A. F, Gomes R, (2015) Fused deposition modeling with polypropylene. Materials Design 83,768776. Dizon JRC, Espera AH, Chen Q, Advincula RC (2018). Mechanical characterization of 3D-printed polymers. Addit Manuf. 20:44–67. Parandoush P, Lin D, (2017) A review on additive manufacturing of polymerfiber composites . Composite Structures 182:3653. Rigon D, Ricotta M, Ardengo G, Meneghetti G (2021) Static mechanical properties of virgin and recycled short glass fiber ‐ reinforced polypropylene produced by pellet additive manufacturing. Fatigue Fract Eng Mater Struct 44:2554 – 2569. Spoerk M, Arbeiter F, Raguž I, et al (2019) Mechanical Recyclability of Polypropylene Composites Produced by Material Extrusi on-Based Additive Manufacturing. Polymers (Basel) 11:1318. Spoerk M, Holzer C, Gonzalez ‐ Gutierrez J (2020) Material extrusion ‐ based additive manufacturing of polypropylene: A review on how to improve dimensional inaccuracy and warpage. J Appl Polym Sci 137:48545. Tekinalp L. H, Kunc V, Velez Garcia G. M, Duty E. C, Love L. J, Naskar K. A, Blue A. C, Ozcan S, (2014) Highly oriented carbon fiberpolymer composites via additive manufacturing. Composites Science and Technology 105: 144150 Wang X, Jiang M, Zhou Z, Gou J, Hui D, (2017) 3D printing of polymer matrix composites: A review and prospective . Composites Part B 110:442458 Weng Z, Wang J, Senthil T, Wu L, (2016) Mechanical and thermal properties of ABS/montmorillonite nanocomposites for fused deposition modeling 3D printing. Materials and Design 102:276283.