Viscoelastic mechanical characterization of a short-fiber reinforced polyethylene tube: Experiments and modelling

Abstract

It is presented in this paper a characterization of the viscoelastic mechanical response of short-fiberreinforced thermoplastic tubes. The tubes are manufactured by helical winding of a composite madeof high-density polyethylene with short glass-fibers as reinforcement. The mechanical behavior of thecomposite lamina is characterized by means of monotonic and loading/unloading tensile tests atdifferent deformation rates for specimens extracted in the axial and circumferential directions of thetube. Based on the experimental results, a three-dimensional Maxwell model with eight parameters, fiveto describe the elastic anisotropy response and three to describe the incompressible-isotropic viscoplasticresponse, is proposed. The comparison of the model results with the experimental data showsthat the model properly captures the material non-linear anisotropic behavior. The only exception is theunloading of the specimens in the circumferential direction, for which the final deformation after thecomplete unloading is largely overestimated. The model is implemented as part of a finite element codeand validated by comparison to experimental measurements of a full-scale test that combines thebending and punching of a tube. The proposed non-linear model for the reinforced polyethylene constitutesa step forward with respect to the classical linear-elastic analysis used for tubes.