scholarly journals Analysis of Fatigue Behavior of High-Density Polyethylene Based on Nonlinear Viscoelastic Measurement under Cyclic Fatigue

1993 ◽  
Vol 25 (7) ◽  
pp. 721-729 ◽  
Author(s):  
Nam-Ju Jo ◽  
Atsushi Takahara ◽  
Tisato Kajiyama
Keyword(s):  
High Density Polyethylene ◽  
Fatigue Behavior ◽  
Cyclic Fatigue ◽  
High Density ◽  
Nonlinear Viscoelastic

scholarly journals Multiaxial Fatigue Behavior of High-Density Polyethylene (HDPE) Including Notch Effect: Experiments and Modeling

2019 ◽  
Vol 300 ◽  
pp. 05001 ◽  
Author(s):  
Mohammadreza Amjadi ◽  
Ali Fatemi
Keyword(s):  
High Density Polyethylene ◽  
Fatigue Behavior ◽  
Equivalent Stress ◽  
Fatigue Tests ◽  
Multiaxial Fatigue ◽  
High Density ◽  
Analytical Models ◽  
Axial Torsion ◽  
Stress Concentration Effect ◽  
Von Mises

High-Density Polyethylene (HDPE) is used in many industries with many applications from automotive industry to biomedical implants. It can be manufactured using different processing techniques including compression molding, injection molding, and blow molding. Multiaxial loading and non-proportionality between different loading sources are inevitable in many applications. It is shown that the common multiaxial fatigue criteria such as von Mises equivalent stress are not able to correlate the multiaxial fatigue data. In this study, multiaxial fatigue behavior of neat HDPE is investigated using hollow tubular specimens through experimental fatigue tests. Axial, torsion, and combined in phase and out-of-phase axial-torsion fatigue tests were conducted. Stress concentration effect on multiaxial fatigue behavior was also studied. Experimental results and analytical models used to account for the aforementioned effects are presented and discussed in this paper.

Relationship Between Fatigue Behavior and Nonlinear Dynamic Viscoelasticity for High-Density Polyethylenes with Different Aggregation States

1998 ◽  
Vol 18 (1-2) ◽  
pp. 63-82
Author(s):  
Nam-Ju Jo ◽  
Kwang-Nak Koh
Keyword(s):  
Fatigue Strength ◽  
Nonlinear Dynamic ◽  
Structural Changes ◽  
Fatigue Behavior ◽  
Cyclic Fatigue ◽  
High Density ◽  
Viscoelastic Parameter ◽  
Dynamic Viscoelasticity ◽  
Crystallite Boundary ◽  
Cyclic Straining

Abstract Relationships between fatigue behavior and nonlinear dynamic viscoelastic properties for the annealed, isothermally crystallized, and oriented high-density polyethylenes (HDPEs) with different molecular aggregation states were intensively discussed. Nonlinear dynamic viscoelasticity under cyclic fatigue was estimated on the basis of nonlinear viscoelastic parameter (NVP) which was defined as the contribution of higher harmonics of Fourier expanded stress signal. Fatigue strength of specimens decreased with an increase in the magnitude of NVP. Thus, NVP can be used as an index of fatigue strength for polymeric solids. Also, higher-order structural changes of specimens by cyclic straining were investigated and it was concluded that the nonlinear dynamic viscoelasticity under cyclic fatigue became dominant with an increase in cyclic straining concentration at the amorphous and/or spherulite or crystallite boundary regions.

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