Molecular Dynamics Investigation of the Effect of Shear during Extrusion on the Permeation Behavior of CH4 in High-Density Polyethylene

Deep-water flexible composite pipes have been widely employed in the domain of deep-water oil and gas transportation, high-density polyethylene (HDPE) is used to seal inner sheath internal media containing H2S CH4, due its favorable barrier properties mechanical properties. The morphological evolution HDPE during extrusion process exerts a direct impact on material’s grand canonical Monte Carlo (GCMC) approach molecular dynamics (MD) method were coupled this study examine under various shear rates as well penetration methane (CH4) rates. results indicate that with an increase rate, undergoes decoupling, leading formation densely arranged, rigidly oriented structure. Gas solubility diffusion coefficients exhibit initial followed by subsequent reduction rate increases, which corresponds microscopic morphology. current simulation can effectively forecast morphology material permeability coefficient provide valuable insights for enhancing effectiveness sheath.