A study on deformation-induced degradation of the compressible polymeric pressurized vessel through a non-equilibrium thermodynamic framework

Abstract

The present paper investigates the degradation of compressible polymers based on the proposed model on strain-induced degradation of incompressible polymers. In a non-equilibrium thermodynamic framework, constitutive equations and evolution laws are derived using the principle of maximum energy dissipation rate and specifying how energy can be stored and dissipated. As a computational model, the governing equations are applied to the pressurized polymeric vessel subjected to the Ogden–Hill compressible hyperelastic material model. To analyze the axisymmetric plane-strain degradable vessel, programming in ANSYS Parametric Design Language (APDL) and the Standard Galerkin Finite Element Method (SGFEM) are applied. The results show that the degradable compressible Ogden–Hill model can also predict the degradation of incompressible polymers subjected to the neo-Hookean model. Results also reveal that the highest dissipation rate and material softening occur at the inner radius of the inflated degradable vessel. Creep-like and stress-relaxation-like responses of the polymeric vessel with time-position-dependent material properties are examined. ANSYS coding indicates good accuracy and efficiency in studying the compressible vessel subjected to inhomogeneous degradation.