PSI - Issue 3

Fatima Majid et al. / Procedia Structural Integrity 3 (2017) 380–386 Fatima MAJID / Structural Integrity Procedia 3 (2017) 380 – 386

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From the figure 3 and 4, we notice a comparable behavior of the PPR material to the HDPE one. Indeed, the Damage is becoming more and more non-linear while the groove depth is getting bigger. Furthermore, the small defects impact is linear.

0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00 0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00

Damage of HDPE notched pipe of 1 mm depth ( γ=1,83) Damage of HDPE notched pipe of 2 mm depth ( γ=1,51) Damage of HDPE notched pipe of 3 mm depth ( γ=1,19) Miner

Damage

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0,20

0,40

0,60

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1,00

Life fraction β

Fig. 3 . HDPE pipe’s unified theory damage.

Damage of CPVC notched pipe of 1 mm depth ( γ=2,27) Damage of CPVC notched pipe of 2 mm depth ( γ=1,88) Damage of CPVC notched pipe of 3 mm depth ( γ=1,26) Miner

Damage

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0,2

0,4

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Life fraction β

Fig. 4. CPVC pipe’s unified theory damage.

The comparison of the modified unified theory damages, as shown in the figure 4, the behavior of the two materials at the half-life stage is nearly similar even if the HDPE pipe’s material is showing a ductile behavior and the CPVC one is showing a brittle one at the neat stages.