Viscoelastic and viscoplastic analysis of polyethylene pipe under pressure loading using space-time finite element method

الملخص EN

In this paper, the viscoelastic and viscoplastic behavior of polyethylene (PE) pipe is studied and analyzed using Space-time finite element method (FEM).

The (FEM) is achieved for Maxwell model and then the program is developed in three dimensions (two-dimension in space and one dimension in time) and applied to (PE) pipe under pressure loading.

The time dependent partial differential equations describing the viscoelastic deformation of (PE) pipe under pressure loading for Maxwell element is solved using variational Galerkin continuous method in an integral process using time slabs.

As a result of this study, the FEM in viscoelastic Maxwell model used to predict the relaxation modulus give accurate result compared to analytical which used Prony series.

The stress increases to large values at the first stage of applied pressure loading and then decrease with increasing time.

The viscoplastic surface density of micro crack is increasing function with increasing plastic strain.