PSI - Issue 3

Fatima Majid et al. / Procedia Structural Integrity 3 (2017) 387–394

392 392

Fatima Majid et al. / Procedia Structural Integrity 3 (2017) 387 – 394

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Miner

Dommage statique basé sur les pressions d'éclatement HDPE Fiabilité basée sur les pressions d'éclatement HDPE

Stage III

Stage I Stage I

Stage II

Damage

β c1

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Fraction de vie( β )

Fig. 5. HDPE’s d amage-reliability evolution in function of the life fraction. For the PPR polymer we crossed the static damage-reliability curves, figure 6, and we find out the critical life fraction of this material βc2 (58%). From this curve also, the stages of damage correspond to initiation (stage I [0, 38%]), propagation (stage II [38%- 78%]) and acceleration (Stage III [78%- 100%]) of it.

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Miner

Stage II

Dommage statique basé sur les pressions d'éclatement PPR Fiabilité basé sur les pressions d'éclatement PPR

Stage I

Stage III

Damage

β c2

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Fraction de vie( β )

Fig. 6. PPR’s damage -reliability evolution in function of the life fraction.

4. Discussion The HDPE and PPR polymers are relatively different materials. In this paper, we leaded a study of their performances by focusing over their mechanical behavior under an internal pressure until rupture. Though the developed approach, we were able to compare the internal pressure evolution and the way it is representing ductility of these materials. We showed that the impact of the internal pressure depends on the necessary time for burst and the duration of each stage (preloading, elastic, plastic and rupture). Moreover, the damage-reliability curves, figure 7,