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

2006 ◽  
Vol 128 (4) ◽  
pp. 572-578 ◽  
Author(s):  
Ozgen U. Colak ◽  
Necmi Dusunceli
Keyword(s):  
Strain Rate ◽  
Rate Equation ◽  
High Density Polyethylene ◽  
Elastic Strain ◽  
High Density ◽  
Cyclic Behavior ◽  
Compression Tests ◽  
Rate Dependency ◽  
Loading And Unloading ◽  
Simulation Results

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.

Effect of Alkaline Treatment on Sawdust Reinforced High Density Polyethylene Composite under Wide Strain Rate

2016 ◽  
Vol 840 ◽  
pp. 103-107 ◽  
Author(s):  
Haliza Jaya ◽  
Mohd Firdaus Omar ◽  
Hazizan Md Akil ◽  
Zainal Arifin Ahmad ◽  
Nik Noriman Zulkepli
Keyword(s):  
Surface Roughness ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Density Polyethylene ◽  
Split Hopkinson Pressure Bar ◽  
Alkali Treatment ◽  
Testing Machine ◽  
High Density ◽  
Rate Condition ◽  
Static And Dynamic Loading

In this study, the alkali treatment of sawdust using different concentration of sodium hydroxide (NaOH) is performed. The purpose of this treatment is to improve the filler-matrix compatibility, thus, enhance the properties of tested specimens under various strain rate condition. The outcome shows the alkali treated sawdust did improve its surface roughness through reduction of sawdust diameter. With this increasing of surface roughness, it will enhance the compatibility between sawdust filler and HDPE matrix. For comparison purpose, the treated and untreated sawdust filler were reinforce in High Density Polyethylene (HDPE) matrix and have been test under static and dynamic loading using Universal Testing Machine (UTM) and Split Hopkinson Pressure Bar (SHPB) apparatus. The results indicate that the stiffness and compression strength properties were improved on treated sawdust composites for both static and dynamic loading compare to untreated sawdust composites.

Structural Performance of Fusion Weld Based on Weld Parameters and Strain Rate in High-Density Polyethylene

2021 ◽  
Vol 50 (2) ◽  
pp. 20210139
Author(s):  
Ahmed Faraz ◽  
Behzad Ahmed Zai ◽  
Salman Nisar ◽  
Asif Mansoor ◽  
Rashid Ali
Keyword(s):  
Strain Rate ◽  
High Density Polyethylene ◽  
High Density ◽  
Structural Performance ◽  
Weld Parameters ◽  
Fusion Weld

scholarly journals Effects of Pimple Height of a Table Tennis Rubber on Ball Rebound Behavior

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 55
Author(s):  
Yoshiya Miyazawa ◽  
Akihiro Hadano ◽  
Katsumasa Tanaka
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Contact Force ◽  
Horizontal Component ◽  
Fe Model ◽  
Table Tennis ◽  
Rate Dependency ◽  
Strain Rate Dependency ◽  
Simulation Results ◽  
Material Tests

The objective of this study was to construct a finite element (FE) model of table tennis rubber (Sandwich rubber) with pimples structure, which can accurately estimate the rebound behavior of the ball at impact, and to investigate effects of its structure on ball rebound behavior. The sandwich rubber is composed of a combination of a rubber and foam layers. The FE model of the sandwich rubber was constructed with non-linearity, strain rate dependency, and energy absorption which were expressed based on the results of material tests. Impact analyses were conducted using the developed model of sandwich rubber and ball with different pimple heights. The simulation results of rebound behavior do not tend to be proportional to the pimple height. The trend of the rebound behavior was mainly affected by the amount of impulse during impact calculated using the horizontal component of the contact force which was varied with changes in pimple height.

The Elastic Behaviour of Metal Powder Compacts

2007 ◽  
Vol 534-536 ◽  
pp. 325-328
Author(s):  
Jose Manuel Prado
Keyword(s):  
Mathematical Model ◽  
Simple Model ◽  
Elastic Strain ◽  
Elastic Behaviour ◽  
Compression Tests ◽  
Linear Elastic ◽  
Loading And Unloading ◽  
Powder Compacts ◽  
The Mathematical Model ◽  
Different Levels

In this work the elastic behaviour of metallic powder compacts is studied. Cylindrical specimens with different levels of density have been submitted to uniaxial compression tests with loading and unloading cycles. The analysis of the elastic loadings shows a non linear elasticity which can be mathematically represented by means of a potential law. Results are explained by assuming that the total elastic strain is the contribution of two terms one deriving from the hertzian deformation of the contacts among particles and another that takes into account the linear elastic deformation of the powder skeleton. A simple model based in a one pore unit cell is presented to support the mathematical model.

Cyclic Behavior of High Density Polyethylene (HDPE)

2010 ◽  
Author(s):  
Necmi Dusunceli ◽  
Bulent Aydemir ◽  
Niyazi U. Terzi ◽  
A. D’Amore ◽  
Domenico Acierno ◽  
...  
Keyword(s):  
High Density Polyethylene ◽  
High Density ◽  
Cyclic Behavior

Dynamic and Quasi-Static Compression Tests for Polylactic Acid Resin Foam

2012 ◽  
Vol 706-709 ◽  
pp. 745-750 ◽  
Author(s):  
Hidetoshi Kobayashi ◽  
Keitaro Horikawa ◽  
Keiko Watanabe ◽  
Kinya Ogawa ◽  
Kensuke Nozaki
Keyword(s):  
Strain Rate ◽  
Polylactic Acid ◽  
High Speed ◽  
Impact Load ◽  
Video Camera ◽  
Compression Tests ◽  
Rate Dependency ◽  
Static Compression ◽  
Acid Resin ◽  
The Impact

In this study, the effect of strain rate on the strength and the absorbed energy of polylactic acid resin foam (PLA-foam), which is generally known as one of carbon-neutral and environmentally-friendly polymers, were examined by a series of compression tests at various strain rates from 0.001 to 750 s-1. For the measurements of the impact load and the displacement of specimen, a special load cell and a high-speed video camera were used, respectively. The flow stress of the PLA-foam strongly depends upon not only strain rate but also density of specimens. Thus, a new technique to eliminate the effect of the difference in the specimen density was proposed and successfully applied. It was also found that the strain-rate dependency of PLA-foam can be expressed by a simple power law.

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