title: Calculating the Optimum Angle of Filament-Wound Pipes in Natural Gas Transmission Pipelines Using Approximation Methods.
abstract: Given the increasing use of composite materials in various industries, oil and gas industry also requires that more attention should be paid to these materials. Furthermore, due to variation in choice of materials, the materials needed for the mechanical strength, resistance in critical situations such as fire, costs and other priorities of the analysis carried out on them and the most optimal for achieving certain goals, are introduced. In this study, we will try to introduce appropriate choice for use in the natural gas transmission composite pipelines. Following a 4-layered filament-wound (FW) composite pipe will consider an offer our analyses under internal pressure. The analyses' results will be calculated for different combinations of angles 15 deg, 30 deg, 45 deg, 55 deg, 60 deg, 75 deg, and 80 deg. Finally, we will compare the calculated values and the optimal angle will be gained by using the Approximation methods. It is explained that this layering is as the symmetrical.
authors.affiliation: Associate Professor Mechanical engineering Department , University of Tabriz , Tabriz , Iran e-mail:  rkhosh@tabrizu.ac.ir.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Reza Khoshravan Azar
authors.affiliation: Student e-mail:  aa_emami@nigc-dist8.ir.
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Emami Satellou
authors.affiliation: Professor e-mail:  shishesaz@yahoo.com Islamic Azad University, Ahvaz Branch , Mechanical engineering Department , Ahvaz , Iran.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Shishesaz
authors.affiliation: Iranian Gas Engineering and Development Company , Tehran, Iran e-mail:  Salavati_b@yahoo.com.
authors.forename: Bahram
authors.initials: B
authors.lastname: Salavati
keywords: approximation method; composite material; natural gas; optimum angle; transmission pipeline