PSI - Issue 41

Cosmin-Florin Popa et al. / Procedia Structural Integrity 41 (2022) 557–563 Author name / Structural Integrity Procedia 00 (2019) 000–000

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3. Results and Discussion The experimental investigation was carried out to determine the impact strength of 48 notched specimens obtained by additive manufacturing that have four difference thicknesses using two materials: 24 specimens from PLA and 24 specimens from PETG. A brittle fracture was observed for each specimens after the tests. In Fig. 3 are presented the specimens from PLA and PETG tested.

Fig. 3. a) Specimens tested from PLA and b) specimens tested from PETG

The Deflection – Impact Force and Deflection – Impact Energy were plotted for each thickness and for each material respectively, Fig 4 and Fig. 5. The results of the 10 mm thickness are depicted in black color lines, 8mm thickness are depicted in orange color line and 6mm thickness are depicted in green color line. The results for specimens with thickness of 4 mm, have not been recorded because of the impactor cell sensitivity. The results for PLA are presented with a solid line, Fig. 4, and with a dash line are presented the results for PETG respectively, Fig.5.

Fig. 4. a) Deflection – Impact Force and b) Deflection – Impact Energy curves of the specimens from PLA with different thicknesses

On each graph can be observed a first elastic impact domain. The results are grouped by thickness. After this first peak the results starts to spread in the crack propagation phase. Behavior on the first and second region are very similar in all specimens from PLA and PETG. The first peak in case of PLA specimens with the thickness of 6 mm has the average in impact force about 104 N with a deflection of 0.085 mm, while in case of PETG specimens with the same thickness the results shown an average impact force of 55.01 N with a deflection of 0.122 mm for the first peak. For the specimens with 10 mm thickness the first peak in case of PLA has the average to impact force of 245.94 N with a deflection of 0.083 mm while in case of PETG, 96.55 N is the average of impact force with 0.134 mm deflection.