PhD opportunities

Mimicking the stress conditions of hydrogen pressurized pipes by plane strain grooved tensile (PSGT) specimens

Thesis proposal

Area of expertiseSciences et génie des matériaux
Doctoral SchoolISMME - Ingénierie des Systèmes, Matériaux, Mécanique, Énergétique
Research unitCentre des Matériaux
KeywordsPressurized pipes, Hydrogen, DIC, PSGT specimen
AbstractPlastic pipes have many applications in today's marketplace and its use continues to grow. They are widely used for carrying water for human consumption, raw water prior to treatment, drainage and sewerage under and without pressure, and water for other purposes. ISO/TC 138 provides a set of standards that specify the requirements for a piping system and its components when made from all types of plastic materials, including all types of reinforced plastics.
ISO 4427-2:2019 [1] specifies the requirements and the testing methods for polyethylene-made (PE) piping systems, within these the testing loading conditions for determining the hydrostatic strength at room and high temperature. Nevertheless, the testing methods and the characteristics of the tubular-shaped geometry are detailed respectively in ISO 1161-1:2006 [2] and ISO 1161-2:2006 [3]. The short-term and long-term response to internal pressure, which are essential for assessing the properties and durability of buried and above-ground thermoplastics pipes, can then be determined. The method is adapted for water-in-water, water-in-air, and water-in-liquid tests of both extruded and injection-moulded tubular test pieces. The tubular pieces are tested using embedded end-caps, transmitting a deep-effect to the piece, which fix the specimen to the testing assembly ensuring watertightness. As a consequence, a biaxial loading is generated: A radial and an axial loading linked correspondingly with the internal pressure and with the effect of the end-cap [4, 5, 6, 7]. Indeed, the method reproduces the same loading conditions as the ones found during the pipeline lifetime; however, it is not adapted for moulding materials, experimental resins being developed for pipes as well as for those pipes, which due to their large diameter, are difficult to test.
ISO 23228:2011 [8] proposed the first satisfactory testing method in which the material can be exposed to stress conditions that mimic internally pressurized end-capped pipes. The stress conditions are reproduced by the use of a plaque geometry having a grooved reduced section called plane strain grooved tensile (PSGT) specimens. They produce a biaxial state of stress when subjected to uni-axial loading, but only if a plane-strain condition is ensured on the groove
minimal section. The plane strain condition in the groove is said to be the result of the difference between the reduced thickness of the groove and the unreduced thickness of the test specimen.
ProfileEngineer and / or Master of Science - Good level of general and scientific culture. Good level of knowledge of French (B2 level in french is required) and English. (B2 level in english is required) Good analytical, synthesis, innovation and communication skills. Qualities of adaptability and creativity. Teaching skills. Motivation for research activity. Coherent professional project.

Prerequisite (specific skills for this thesis):

Applicants should supply the following :
• a detailed resume
• a copy of the identity card or passport
• a covering letter explaining the applicant's motivation for the position
• detailed exam results
• two references : the name and contact details of at least two people who could be contacted
• to provide an appreciation of the candidate
• Your notes of M1, M2
• level of English equivalent TOEIC
to be sent to
FundingConcours pour un contrat doctoral