0
RESEARCH PAPERS

# Modeling Viscoelastic and Viscoplastic Behavior of High Density Polyethylene (HDPE)

[+] Author and Article Information
Ozgen U. Colak1

Department of Mechanical Engineering, Yildiz Technical University, Istanbul 34349, Turkeyozgen@yildiz.edu.tr

Necmi Dusunceli

Department of Mechanical Engineering, Yildiz Technical University, Istanbul 34349, Turkeyndusunce@yildiz.edu.tr

1

Corresponding author.

J. Eng. Mater. Technol 128(4), 572-578 (May 11, 2006) (7 pages) doi:10.1115/1.2345449 History: Received August 02, 2005; Revised May 11, 2006

## Abstract

The viscoelastic and viscoplastic behaviors of high density polyethylene (HDPE) under uniaxial monotonic and cyclic loading are modeled using the modified viscoplasticity theory based on overstress (VBO). The viscoelastic modeling capabilities of the modified VBO are investigated by simulating the behavior of semicrystalline HDPE under uniaxial compression tests at different strain rates. In addition, the effects of the modification (introducing the variable “$C$” into an elastic strain rate equation) on VBO that has been made to construct the change in the elastic stiffness while loading and unloading are investigated. During first loading and unloading, the modification in the elastic strain rate equation improves the unloading behavior. To investigate how the variable “$C$” that is introduced in the elastic strain rate equation evolves during reloading, the cyclic behavior of HDPE is modeled. For a complete viscoelastic and viscoplastic behavior, the relaxation and creep behaviors of HDPE are simulated as well in addition to stress and strain rate dependency. The influences of the strain (stress) levels where the relaxation (creep) experiments are performed are investigated. The simulation results are compared with the experimental data obtained by Zhang and Moore (1997, Polym. Eng. Sci., 37, pp. 404–413). A good match between experimental and simulation results are observed.

<>

## Figures

Figure 1

Prediction results of HDPE under uniaxial compression test at the strain rate of 1.E-03/s. “●” denotes the experimental data obtained from Zhang and Moore (3).

Figure 2

Simulation results of HDPE under uniaxial compression test at the strain rate of 1.E-04/s. “●” denotes the experimental data obtained from Zhang and Moore (3).

Figure 3

Prediction results of HDPE under uniaxial compression test at the strain rate of 1.E-05/s. “●” denotes the experimental data obtained from Zhang and Moore (3).

Figure 4

The simulation results of HDPE under uniaxial compression tests at the strain rates of 1.E-03, 1.E-04, and 1.E-05/s

Figure 5

A comparison of stress-strain behaviors of HDPE under compression loading and unloading at the strain rate of 1.E-03/s when the classical VBO (C=1) and the modified one are used (C=variable)

Figure 6

Figure 7

Prediction result of a cyclic test of HDPE at the strain rate of 1.E-04/s. Experimental data is obtained from Zhang and Moore (3).

Figure 8

Prediction result of HDPE under uniaxial compression test at the stress rate of 26.5N∕s. “●” denotes the experimental data.

Figure 9

Prediction result of HDPE under uniaxial compression test at the stress rate of 3N∕s. “●” denotes the experimental data.

Figure 10

Model predictions for multistrain rate and relaxation tests. (a)–(b) Strain rate of 1.E-04/s; (b)–(c) relaxation for 450s; (c)–(d) strain rate of 1.E-02/s; (d)–(e) strain rate of 1.E-03/s; and (e)–(f) relaxation for 125s. “●” denotes the experimental data obtained by Zhang and Moore (3).

Figure 11

Prediction result of HDPE under relaxation tests at two strain levels. “●” denotes the experimental data obtained by Zhang and Moore (3).

Figure 12

Predictions for multistrain rate and relaxation tests when the classical VBO is used (C=1). Loading conditions are given in Fig. 1.

Figure 13

Axial stress-strain curve during multiple creep on HDPE: (a)–(b) loading rate of 10N∕s; (b)–(c) creep for 980s; (c)–(d) loading rate of 1N∕s; (d)–(e) creep for 1000s; (e)–(f) loading rate of 100N∕s; and (f)–(g) creep for 240s. Experimental data is from Zhang and Moore (3).

Figure 14

Predictions of the multiple creep test of HDPE using the modified VBO. Experimental data is from Zhang and Moore (3).

## Discussions

Some tools below are only available to our subscribers or users with an online account.

### Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related Proceedings Articles
Related eBook Content
Topic Collections