Deformation mechanisms in oriented high-density polyethylene

1973 ◽  
Vol 8 (1) ◽  
pp. 23-36 ◽  
Author(s):  
R. J. Young ◽  
P. B. Bowden ◽  
J. M. Ritchie ◽  
J. G. Rider
2021 ◽  
Vol 229 ◽  
pp. 01002
Author(s):  
Rabiaa Elkori ◽  
Amal Laamarti ◽  
Khalid Elhad ◽  
Abdelilah Hachim

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.


1978 ◽  
Vol 13 (3) ◽  
pp. 639-646 ◽  
Author(s):  
S. G. Burnay ◽  
G. W. Groves

1992 ◽  
Vol 25 (19) ◽  
pp. 5036-5053 ◽  
Author(s):  
Z. Bartczak ◽  
A. S. Argon ◽  
R. E. Cohen

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 527
Author(s):  
David Viljoen ◽  
Matthieu Fischer ◽  
Ines Kühnert ◽  
Johan Labuschagné

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.


2003 ◽  
Vol 774 ◽  
Author(s):  
Susan M. Rea ◽  
Serena M. Best ◽  
William Bonfield

AbstractHAPEXTM (40 vol% hydroxyapatite in a high-density polyethylene matrix) and AWPEX (40 vol% apatite-wollastonite glass ceramic in a high density polyethylene matrix) are composites designed to provide bioactivity and to match the mechanical properties of human cortical bone. HAPEXTM has had clinical success in middle ear and orbital implants, and there is great potential for further orthopaedic applications of these materials. However, more detailed in vitro investigations must be performed to better understand the biological interactions of the composites and so the bioactivity of each material was assessed in this study. Specifically, the effects of controlled surface topography and ceramic filler composition on apatite layer formation in acellular simulated body fluid (SBF) with ion concentration similar to those of human blood plasma were examined. Samples were prepared as 1 cm × 1 cm × 1 mm tiles with polished, roughened, or parallel-grooved surface finishes, and were incubated in 20 ml of SBF at 36.5 °C for 1, 3, 7, or 14 days. The formation of a biologically active apatite layer on the composite surface after immersion was demonstrated by thin-film x-ray diffraction (TF-XRD), environmental scanning electron microscopy (ESEM) imaging and energy dispersive x-ray (EDX) analysis. Variations in sample weight and solution pH over the period of incubation were also recorded. Significant differences were found between the two materials tested, with greater bioactivity in AWPEX than HAPEXTM overall. Results also indicate that within each material the surface topography is highly important, with rougher samples correlated to earlier apatite formation.


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