پديدآورندگان :
Kheradmehr A. M.Sc of Mechanical Engineering, Faculty of Science and Research Branch of Islamic Azad University Bushehr Branch, Iran , Armaghani T. Assistant Professor of Mechanical Engineering, MahdiShahr Branch, Islamic Azad University, Mahdishahr, Semnan, Iran , Izadi M Assistant Professor of Mechanical Engineering, Faculty of Science and Research Branch of Islamic Azad University Bushehr Branch, Iran , Mohammaddoost H. hamed.new_21@yahoo.com Phd student of Chemical Engineering,Department, of Chemical Engineering,Shiraz Branch, Islamic Azad University, Shiraz, Iran
كليدواژه :
Gas Transmission , 3 , Layer Polyethylene Coating , Finite Element Method , Hydrostatic Test , Stress.
چكيده فارسي :
Coating is one of the important aspects to consider in construction of gas transmission
pipelines and the most common protection coating which applied is 3-layer
polyethylene. The main goal of this study is the analysis of the effect of hydrostatic
test on interlayer bonding of 3-layer polyethylene coating. Finite element method
(F.E.M) by ANSYS software employed for modeling and calculations. Integrated
octagonal elements with 8 node and 24 degrees of freedom has been used and grid
independency evaluated. Soil weight and internal hydropressure has been considered
and plannar strain assumed in problem solution. Von mises strain and stress show that
pipe material maintains in safe margin below yield strength, but plastic deformation
occurs in epoxy resin, binder and polyethylene. This deformation reduce interlayer
bonding of polyethylene and also pipe to coating. Therefore in the cases with high
corrosion risk, due to soil corrosive conditions application of other protection
coatings like polyurethane or polyuria is proposed.
