Stress-Strain State of a Welded Joint in Welding a Saddle Branch to a Polyethylene Pipe under Low Temperatures

Abstract

Purpose of research. The aim of the study is a comparative analysis of the stress-strain states of welded joints during welding of saddle branches to existing gas pipelines under normal conditions using standard technology and low temperatures using the proposed technology.Methods. To achieve the goal, a numerical implementation of the mathematical model of the thermoelastic state by the finite element method in the Python programming environment using the Fenics computing package was performed. The computational grid was built using the GMSH program. Visualization of the obtained results was implemented using the Paraview package.Results. On the basis of computational experiments of welding a saddle branch to an existing gas pipeline at permissible and low ambient temperatures, the dynamics of the temperature fields, stresses and strains in the heataffected zone are almost identical.Conclusion. The calculation results showed that when welding saddle branches to polyethylene pipes of existing gas pipelines at low temperatures using the proposed technology, the main physical and mechanical processes will proceed as in welding under normal conditions and provide the necessary strength.