PSI - Issue 3

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 3 (2017) 387 – 394 Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 3 (2017) 387 – 394

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ScienceDirect

Procedia Structural Integrity 3 (2017) 387–394

Copyright © 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. Abstract Many polymers have been developed through the years to satisfy the continuous demand of industrials and the development of the fields of usage of these materials. Indeed, the High Density Polyethylene (HDPE) and the Poly Propylene (PPR) are famous materials and have diversified utilizations. To predict their mechanical behavior, we leaded burst tests on multilevel groove notched pipes and we compared the general behavior of the internal pressure of burst. We noticed a drastic drop in the burst pressure in function of the life fraction. The HDPE and PPR materials are showing a ductile behavior with two characteristic pressures at the end of the elastic phase and the rupture phase. The HDPE has a stable plastic phase and show a perfect ductile behavior. Meanwhile the PPR have a short plastic phase and show similarities to an old HDPE pipe tendency. It is shown that the PPR has reverse characteristic pressures at the opposite of the HDPE ones. We have noticed that the two materials change the corresponding level of loading to recover the noticed deformation in the plastic phase. The obtained parameters allowed us to establish new concepts of damage modeling through the modification of usual nonlinear models existing in the literature which has been initially proposed for steel materials. The static model of the unified theory which have been developed based on the burst pressure parameters and allowed us to predict the burst pressure damage evolution according to the life fraction, representing the harmfulness of the notch. The static damage evolution is representing the damage corresponding to each notch. Then, we compared the effect of the notch level on PPR and HDPE materials. Finally, we analyzed the noticeable discrepancies between PPR and HDPE and we showed the advantages of such models to make the quick checks easier and reliable by only using static test of burst. © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Mechanical behavior prediction of PPR and HDPE polymers through newly developed nonlinear damage-reliability models Fatima Majid a , * , Abderazzak Ouardi a , Mohamed Barakat a , Mohamed Elghorba a a Laboratoire de contrôle et de caractérisation des matériaux et des structures, Génie Mécanique, Ecole Nationale Supérieure d’ Electricité et de Mécanique, Université Hassan II, Km7, route ELJADIDA, 20000, Casablanca, MAROC. Abstract Many polymers have been developed through the years to satisfy the continuous demand of industrials and the development of the fields of usage of thes materials. Indeed, the High Den i y Poly thyle e (HDPE) and the Poly Propylen (PPR) ar famous materials and have diversified uti izations. To pred ct their mechanical behavior, we leade burst tests on multil vel groov notched pip s nd we compared the general behavior of the int nal pressure of burst. W noticed a drastic drop in the bu st pressure in functio of the life fraction. Th HDPE nd PPR materials are showing a duc ile behavior with two characteristic p essure at the end of the elastic phase and the rupture phase. The HDPE has a stable plastic phase and sh w a perfect ductil behavior. Meanwhil the PPR have a short plastic phase and show similarities to an old HDPE ipe te ency. It is shown that the PPR has revers c aracteristic pre su es at he opposite of the HDPE ones. We have noticed that th two mater al cha ge the corresponding l vel of lo ding o recove the noticed deforma ion in the plastic phase. The obtained parameters allowed us to establish new conc pts damage modeling through the modific of usual nonline r models existing in the li ature hich has been nitially proposed for steel materia s. T e static model of the u ified theory which hav be n developed based on the burst pressure parameters an allow d us to predict the burst pressure damage volution according to th lif fraction, represen ing the ha mf lness of the notch. The static damage evolution is pres nting th damage correspo ding to each no ch. Then, we compared the eff ct t tc lev l on PPR and HDPE materials. Finally, we an lyzed the noticeable discrepa cies between PPR and HDPE and we showed he ad antages of such models to make the quick checks asier a d reliable by only using static test of burst. © 2017 The Authors. Published by Elsevier B.V. Peer-review under espons bility of the Scientific Committee of IGF Ex-Co. Keywords: PPR; HDPE; Damage models; Unified theory; Mechanical behavior. XXIV Italian Group of Fracture Conference, 1-3 March 2017, Urbino, Italy Mechanical behavior prediction of PPR and HDPE polymers through newly developed nonlinear damage-reliability models Fatima Majid a , * , Abderazzak Ouardi a , Mohamed Barakat a , Mohamed Elghorba a a Laboratoire de contrôle et de caractérisation des matériaux et des structures, Génie Mécanique, Ecole Nationale Supérieure d’ Electricité et de Mécanique, Université Hassan II, Km7, route ELJADIDA, 20000, Casablanca, MAROC.

Keywords: PPR; HDPE; Damage models; Unified theory; Mechanical behavior.

* Corresponding author. Tel.: +212 663 49 90 78; E-mail address: majidfatima9@gmail.com * Corresponding author. Tel.: +212 663 49 90 78; E-mail ad ress: majidfatima9@gmail.com

2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. 2452-3216 © 2017 The Authors. Published by Elsevier B.V. Peer review under r sponsibility of the Scientific Committee of IGF Ex-Co.

2452-3216 Copyright © 2017 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer-review under responsibility of the Scientific Committee of IGF Ex-Co. 10.1016/j.prostr.2017.04.043