PSI - Issue 19

Aissa Ouballouch et al. / Procedia Structural Integrity 19 (2019) 433–441 Aissa Ouballouch et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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3.2. Tensile testing The average ultimate tensile strength for each sample is shown in Table 3. These results were used to create Figure 8.

Table 3. Tensile testing results

Sample

Material

Ultimate Tensile Strength

1 2 3 4 5 6 7 1 2 3 4 5 6 7

GRPA with +-45° (orientation)

24.52 MPa 23.67 MPa 22.75 MPa 21.22 MPa 23.54 MPa 23.94 MPa 26.29 MPa 33.65 MPa 33.33 MPa 25.63 MPa 39.54 MPa 36.48 MPa 37.41 MPa 37 MPa

KRPA with +-45° (orientation)

Figure 8-a) shows the variation of tensile strength of reinforced PA parts with altering of extrusion temperature. For both materials, there is increase of ultimate tensile strength with rising of temperature however the impact in case of glass reinforcement is lower than Kevlar reinforcement case. Figure 8-b) depicts the evolution of ultimate tensile strength of studied reinforced PA parts. The tensile strength is affected by the print speed. The variation of GRPA strength has a downward trend while that of KRPA has an upward trend. The influence of printing velocity on these both materials is opposite. From Figure 8-c), it is shown that the evolution of tensile strength for both materials keep increasing with the rising of layer thickness expect at LT= 0.15 mm where the strength represents the highet value for KRPA. This can be intepreted by the fact that at this layer thickness the suitable multiple heat transfer is achieved between consecutive layers and lines. This thickness value yields lower voids and good bonding. However at thickness slice 0.2 mm, the UTS of KRA decreases which may be due to the lower number of interfaces.

34 36 38

36 38 40

245 250 255 260 265 20 22 24 26 34 36 38 K GR R P P A A Extrusion temperature [°C] UTS of Reinforced PA versus extrusion temperature

b)

c)

a)

UTS of Reinforced PA versus layer thickness

UTS of Reinforced PA versus print speed

22 24 2 3 6 4

50 55 60 65 70 20 22 2 3 4 2 K GR R P P A A Print speed [mm/s]

UTS [MPa]

UTS [MPa]

UTS [MPa]

K GR R P P A A

0,10

0,15

0,20

Layer Thickness [mm]

Fig. 8. UTS of RPA as function of processing parameters