scholarly journals The Tensile Behaviour of Highly Filled High-Density Polyethylene Quaternary Composites: Weld-Line Effects, DIC Curiosities and Shifted Deformation Mechanisms

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 527
Author(s):  
David Viljoen ◽  
Matthieu Fischer ◽  
Ines Kühnert ◽  
Johan Labuschagné
Keyword(s):  
High Density Polyethylene ◽  
Tensile Testing ◽  
Weld Line ◽  
High Density ◽  
Image Correlation ◽  
Interactive Effects ◽  
Deformation Mechanisms ◽  
Tensile Behaviour ◽  
Combined Time Series ◽  
Stress Whitening

The interactive effects between additives and weld lines, which are frequent injection-moulding defects, were studied in high-density polyethylene (HDPE) and compared to weld-line-free reference samples. These materials were formulated around a D- and I-optimal experimental design, based on a quadratic Scheffé polynomial model, with up to 60 wt% calcium carbonate, masterbatched carbon black and a stabiliser package. Where reasonable and appropriate, the behaviours of the systems were modelled using statistical techniques, for a better understanding of the underlying trends. The characterisations were performed through the use of conventional tensile testing, digital image correlation (DIC) and scanning electron microscopy (SEM). A range of complex interactive effects were found during conventional tensile testing, with DIC used to better understand and explain these effects. SEM is used to better understand the failure mechanics of some of these systems through fractography, particularly regarding particle effects. A measure is introduced to quantify the deviation of the pre-yield deformation curve from the ideal elastic case. Novel analysis of DIC results is proposed, through the use of combined time-series plots and measures quantifying the extent and localisation of peak deformation. Through this, it could be found that strong shifts in the deformation mechanisms occur as a function of formulation and the presence/absence of weld lines. Primarily, changes are noted in the onset of continuous inter- and intralamellar slip and cavitation/fibrillation, seen through the onset of localised deformation and stress-whitening.

Morphology and Stress Whitening of Heterophasic Poly(propylene) Copolymer/High Density Polyethylene Blends

2012 ◽  
Vol 312 (1) ◽  
pp. 34-42 ◽  
Author(s):  
Hee Jung Jang ◽  
Soon-Deok Kim ◽  
Wonsook Choi ◽  
Yong Sung Chun
Keyword(s):  
High Density Polyethylene ◽  
High Density ◽  
Polyethylene Blends ◽  
Poly Propylene ◽  
Stress Whitening

scholarly journals Numerical and experimental study of the Behaviour of notched HDPE

2021 ◽  
Vol 229 ◽  
pp. 01002
Author(s):  
Rabiaa Elkori ◽  
Amal Laamarti ◽  
Khalid Elhad ◽  
Abdelilah Hachim
Keyword(s):  
Experimental Study ◽  
Tensile Test ◽  
High Density Polyethylene ◽  
Room Temperature ◽  
Industrial Applications ◽  
High Density ◽  
Deformation Mechanisms ◽  
Commercial Software ◽  
Notched Specimens ◽  
Software Code

It is important to study the Behaviour of high-density polyethylene (HDPE) under notch effects as it is widely used in industrial applications (Qi, 2018). However, there are only a few studies on the Behaviour of HDPE with defects, this work aims to study the deformation mechanisms under a tensile test experimentally performed on blank and notched specimens at constant speed and room temperature, and by developing our study by simulating HDPE using commercial software code.

Tensile Stress-Strain Properties and Elastic Modulus of PE 4710 Cell Classification 445574C High Density Polyethylene Pipe Material

2013 ◽  
Author(s):  
Timothy M. Adams ◽  
Jie Wen ◽  
Shawn Nickholds ◽  
Douglas Munson
Keyword(s):  
Elastic Modulus ◽  
High Density Polyethylene ◽  
Tensile Testing ◽  
Axial Direction ◽  
Tensile Tests ◽  
High Density ◽  
Pipe Material ◽  
Yield Strain ◽  
Cell Classification ◽  
Hdpe Pipe

For corroded piping in low temperature systems replacement of buried carbon steel pipe with high density polyethylene (HDPE) pipe is a cost-effective solution. The ASME Boiler and Pressure Vessel Code, Section III, Division 1, Code Case N755-1 currently permits the use of HDPE in buried Safety Class 3 piping systems. This paper presents the results of tensile testing of PE 4710 cell classification 445574C pipe compliant with the requirements of Code Case N755-1. This information was developed to support and provide a strong technical basis for tensile properties of HDPE pipe. The data may also be useful for applications of HDPE pipe in commercial electric power generation facilities and chemical, process, and waste water plants via its possible use in the B31 series piping codes. The paper provides values for yield stress, yield strain, ultimate strain, and elastic modulus. The standard tensile tests were conducted consistent with the requirements of ASTM D638-10. Specimens were cut in the axial direction from cell composition PE 4710 cell classification 445574C HDPE piping spools. In addition, the results are compared to previous tensile testing conducted on the PE 3608 cell classification 345464C and PE 4710 cell classification 445474C HDPE materials.

Tensile Testing and Material Property Development of High Density Polyethylene Pipe Materials

2008 ◽  
Author(s):  
Timothy M. Adams ◽  
Siegrid Hall ◽  
Rudolph J. Scavuzzo ◽  
Douglas Munson ◽  
Jeffrey W. Andrasik ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
High Density Polyethylene ◽  
Tensile Testing ◽  
Water Systems ◽  
High Density ◽  
Test Program ◽  
Polyethylene Pipe ◽  
Cell Class ◽  
Service Water ◽  
Division 1

Degradation of service water systems is a major issue facing nuclear power plant owners, and many plants will require repair or replacement of existing carbon steel piping components. High Density Polyethylene pipe has been used in non-safety service water systems for over nine years and found to perform well, but it is not currently permitted in the ASME Section III Boiler and Pressure Vessel Code, Division 1 for use in nuclear safety-related systems. To assist in the implementation of High Density Polyethylene pipe in the ASME Boiler and Pressure Vessel Code, Section III, Division 1 for Safety Class 3 applications, EPRI initiated a High Density Polyethylene pipe and pipe material testing program. This test program includes tensile testing and fatigue testing of High Density Polyethylene piping and piping components and the development of slow crack growth data. To determine the material and engineering properties needed, extensive tensile testing of specimens cut from High Density Polyethylene pipe was conducted. The initial tensile test program was conducted on PE 3408 with cell classification 345464C and a second, not yet finalized, phase was added to test PE 4710 with cell classification 445474C. The data developed during the testing were used to establish ultimate strain, elastic moduli, yield stress and yield strain values for both new and aged materials. Because extruded HDPE properties vary in the hoop and axial directions and the properties are highly affected by temperature, specimens were cut in both the hoop and axial directions and were tested at temperatures ranging from 50° F to 180° F. This paper provides a description and overview of the PE 3408 cell class 345464C test program. In addition, an overview and summary of the test results for the PE 3408 cell class 345464C are provided.

Determination of Tensile Elastic Modulus in High Density Polyethylene Piping at Seismic Strain Rates

2012 ◽  
Author(s):  
Douglas Munson ◽  
Timothy M. Adams ◽  
Shawn Nickholds
Keyword(s):  
Elastic Modulus ◽  
Carbon Steel ◽  
High Density Polyethylene ◽  
Tensile Testing ◽  
Seismic Loading ◽  
High Density ◽  
Strain Rates ◽  
Polyethylene Pipe ◽  
Seismic Strain ◽  
Tensile Elastic Modulus

For corroded piping in low temperature systems, such as service water systems in nuclear power plants, replacement of carbon steel pipe with High Density Polyethylene pipe is a cost-effective solution. Polyethylene pipe can be installed at much lower labor costs than carbon steel pipe and High Density Polyethylene pipe has a much greater resistance to corrosion. Data was developed by the three testing tasks for use in the seismic design of above ground High Density Polyethylene Piping systems. This paper presents the results of testing to determine the relationship between tensile elastic modulus and strain rates commensurate with seismic loading. This is accomplished by first establishing a seismic strain rate for High Density Polyethlene using detailed finite element analysis. The results of this analysis are used to establish a test matrix tensile testing. Next, tensile tests are conducted using standard ASTM D-638 Type III tensile specimens. The tensile testing is conducted at three pull speeds to establish a basic relationship between tensile elastic modulus and strain rates. This relationship is then used to calculate the modulus at the strain rates expected under seismic loading. This paper presents the results of this testing and the suggested tensile modulus for use in seismic analysis.

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