PSI - Issue 34

Dario Santonocito et al. / Procedia Structural Integrity 34 (2021) 211–220 D. Santonocito et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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48 MPa reported in the datasheet. On the other hand, the elongation at break ε f = 0.304±0.091 is higher compared to the nominal value of 0.24. Stoia and coworkers (Stoia et al. (2019)) evaluated the mechanical properties of PA12 obtained by SLS and different energy densities. The more performant printing setup, with a 0° orientation angle, reports E= 1264±10 MPa; σ U = 27.1±0.8 MPa and ε f = 0.058±0.002. Lammens et al. (Lammens et al. (2017)) reports E= 1903±15 MPa; σ U = 49.4±0.2 MPa and ε f = 0.155±0.004. Santonocito, for PA12 specimens obtained by Multijet Fusion (MJF™) printing system, reports E= 1732±130 MPa; σ U = 46.5±1.8 MPa and ε f = 0.1232±0.0194 (Santonocito (2020)). The different reported values of such 3D-printed material, show how its mechanical performance are severally dependent on the printing parameters. 4.2. Static Thermographic Method During static tensile test, the temperature evolution of the specimens was monitored with an infrared camera. The temperature values have been referred to the initial temperature of the specimen T 0 and the temperature signal has been filtered with a rlowess filter, with a data span of 5%, to reduce the outliers and highlight the thermoelastic trend. In Fig. 5 are reported the filtered temperature trend and the applied nominal stress versus the test time.

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Fig. 5. Temperature evolution vs. applied stress during static tensile test on PA12 specimens.