The Simulation of Ultra-High Molecular Weight Polyethylene Cryogenic Pipeline Stress-Strain State

Abstract

At present the production of polymer materials is developing intensively, new materials, comparable with steels in their strength properties have recently appeared. In this connection, the analysis of polymer materials applied in the pipe industry has been carried out, and the use of ultra-high molecular weight polyethylene (UHMWPE) is proposed as a structural pipeline material, allowing pipes to operate at cryogenic temperatures. The focal point of the article is the consideration of the fracture mechanisms of those materials and the nature of the change in the mechanical properties of UHMWPE under cryogenic temperatures, also taking into account the creep process. The expression for determining the value of the creep modulus depending on the temperature and operating time was obtained. A method is proposed for conducting initial strength estimation. Moreover, the computer model of stress-strain state of an underground cryogenic polymer pipeline for liquefied natural gas transportation is obtained. The results of simulation depict the potential possibility of using of UHMWPE for the cryogenic pipeline construction

Thermally Activated Crack Growth and Fracture Toughness Evaluation of Pipeline Steels Using Acoustic Emission

“…Engineering approaches to determining the strength parameters [1][2][3] of fracture mechanics occupy an important place in the direction of increasing the service life of technological objects and various materials [4,5]. The modern global oil and gas industry is experiencing a serious upswing in all sectors, and predicting strength and durability is of paramount importance [6][7][8].…”

Using the Magnetic Anisotropy Method to Determine Hydrogenated Sections of a Steel Pipeline

“…Therefore, timely detection of the pipeline section where the pipe wall was hydrogenated is a possible method of failure prevention [13][14][15]. The above conclusion is valid for both compressed hydrogen pipelines, where local hydrogenation of the pipe wall cannot be excluded, e.g., due to plastic deformation caused by soil movement [16] and other bending stresses [17][18][19], and pipelines carrying natural gas and oil products [20][21][22]. At the same time, currently existing methods of detecting increased hydrogen content in metal structures, both by measuring its concentration directly or indirectly-based on the change in mechanical properties of the metal-are destructive, since both use specimens cut from the analysed structure for research.…”