Issue 43

F. Majid et alii, Frattura ed Integrità Strutturale, 43 (2018) 79-89; DOI: 10.3221/IGF-ESIS.43.05 79 Continuum damage modeling through theoretical and experimental pressure limit formulas Fatima Majid, Mohamed Elghorba University of Hassan II, National Superior School of Electricity and Mechanics Casablanca (ENSEM), LCCMMS, Morocco majidfatima9@gmail.com , http://orcid.org/0000-0001-8909-8232 A BSTRACT . In this paper, we developed a mathematical modeling to represent the damage of thermoplastic pipes. On the one hand, we adapted the theories of the rupture pressure to fit the High Density Polyethylene (HDPE) case. Indeed, the theories for calculating the rupture pressure are multiple, designed originally for steels and alloys. For polymer materials, we have found that these theories can be adapted using a coefficient related to the nature of the studied material. The HDPE is characterized by two important values of pressure, deduced from the ductile form of the internal pressure’s evolution until burst. For this reason, we have designed an alpha coefficient taking into account these two pressures and giving a good approximation of the evolution of the experimental burst pressures through the theoretically corrected ones, using Faupel’s pressure formula. Then, we can deduce the evolution of the theoretical damage using the calculated pressures. On the other hand, two other mathematical models were undertaken. The first one has given rise to an adaptive model referring to an expression of the pressure as a function of the life fraction, the characteristic pressures and the critical life fraction. The second model represents a continuum damage model incorporating the pressure equations as a function of the life fraction and based on the burst pressure’s static damage model. These models represent important tools for industrials to assess the failure of thermoplastic pipes and proceed quick checks. K EYWORDS . Continuum Damage; HDPE; Burst pressure; Life fraction. Citation: Majid, F., Elghorba, M., Continuum damage modeling through theoretical and experimental pressure limit formulas, Frattura ed Integrità Strutturale, 43 (2018) 79-89. Received: 25.09.2017 Accepted: 03.11.2017 Published: 01.01.2018 Copyright: © 2018 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION olymers have changed all facets of the industrial life and are almost a part of all fields, including the medical and food industries. Universities, organizations and industrial companies are getting deeply concerned about these materials. They are contributing to the advance and the prosperity of several industries such as petrochemicals, gas, water networks and slurries’ transport. This multitude of applications explains the huge number of product ranges, which have been produced. Many researches were interested to the extreme environmental conditions, the manufacturing methods P