Cyclic viscoplasticity of high-density polyethylene: Experiments and modeling

Published Date
Computational Materials Science
April 2007, Vol.39(2):465–480, doi:10.1016/j.commatsci.2006.07.014

• Author 

• A.D. Drozdov ^a,,
• J.deC. Christiansen ^b

• aDepartment of Chemical Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105, Israel
• bDepartment of Production, Aalborg University, Fibigerstraede 16, DK–9220 Aalborg, Denmark

Received 3 July 2006. Revised 27 July 2006. Accepted 27 July 2006. Available online 7 September 2006. 

Abstract

Observations are reported on high-density polyethylene in uniaxial cyclic tensile tests. Two deformation programs are considered. In tests with a strain-controlled program, each cycle of deformation involves tension up to a maximum engineering strain ϵ_maxand retraction down to the zero stress. In tests with a stress-controlled program, any cycle of deformation consists of tension up to a maximum engineering stress σ_maxand retraction down to some minimum engineering stress σ_min. The study focuses on low-cycle programs with a constant cross-head speed and small strains.

A constitutive model is derived in viscoplasticity of semicrystalline polymers at isothermal three-dimensional cyclic deformations. Material constants in the stress–strain relations are found by fitting the experimental data. Good agreement is demonstrated between the observations and the results of numerical analysis. Some interesting phenomena are revealed by means of numerical simulation of cyclic deformations.

Keywords

High-density polyethylene

Viscoplasticity

Cyclic deformation

Constitutive modeling

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