Determination of slow crack growth behaviour of polyethylene pressure pipes with cracked round bar test

Kratochvilla, Thomas R.; Frank, Andreas; Pinter, Gerald

doi:10.1016/j.polymertesting.2014.10.002

Cited by 30 publications

(10 citation statements)

References 14 publications

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“…However, it is much less sensitive to stress in the brittle domain. Recently, several studies focused on characterization and prediction of slow crack propagation and brittle failure in the pipes. In these studies, the brittle failure is predicted based on linear elastic fracture mechanics.…”

Section: Introductionmentioning

confidence: 99%

Accelerated testing method to estimate the long‐term hydrostatic strength of semi‐crystalline plastic pipes

Taherzadehboroujeni

Kalhor

Fahs

et al. 2019

Polymer Engineering & Sci

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The ability to quickly develop predictions of the service lifetime of plastic pipes at different load levels allows designers to choose the best plastic material and design pipe for a specific application. Additionally, it helps material producers to rapidly design, manufacture, test, screen, and modify the base polymeric material. The aim of this study is to introduce a combined experimental and analytical framework to develop accelerated lifetime estimates for semicrystalline plastic pipes which is sensitive to the structure, orientation, and morphology changes introduced by changing processing conditions. To accomplish this task, high density polyethylene (HDPE) is chosen as the exemplary base material and custom fixtures are developed to admit tensile and hoop burst tests on the as-manufactured HDPE pipes. A pressure-modified Eyring flow equation is employed to predict the rupture lifetime of HDPE pipes using the measured mechanical properties under uniaxial tensile and compression loading in different temperatures and strain rates. The method allows the prediction of pipe service lifetimes in excess of 50 years using experiments conducted over approximately 10 days instead of the traditional 13 months. POLYM. ENG. SCI., 60:879-888, 2020.POLYMER ENGINEERING AND SCIENCE-2020 FIG. 7. The compression stress-strain results under different strain rates and elevated temperature of 60 C. Solid lines are the tangent lines and circles are the yield points. a) Model predictions of time-to-failure and biaxial creep tests results at room temperature and (b) the model predictions at three different temperature compared with experimental data for a PE100 grade pipe.

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Section: Introductionmentioning

confidence: 99%

Accelerated testing method to estimate the long‐term hydrostatic strength of semi‐crystalline plastic pipes

Taherzadehboroujeni

Kalhor

Fahs

et al. 2019

Polymer Engineering & Sci

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“…However, the total failure cycle numbers Nf=1138248 cycles found by simulation at an internal pressure P=10bar is compared to that obtained by experimental data [15] Nf=1188036 cycles shown a good agreement with an error e=0.04. The results for crack kinetics and fatigue lifetime predictions for pipe PE100 have already been published previously by the authors [4,8,14,15,[20][21][22][23][24].…”

Section: Internal Pressurementioning

confidence: 99%

“…It can be observed that increasing of inside diameter of pipe leads to an increase of the fatigue lifetime. In recent studies it has been demonstrated that there is a linear correlation between the inside diameter and the fatigue lifetime [14].…”

Section: Inside Diametermentioning

confidence: 99%

“…With the objective of ensuring sufficient lifetimes of such pressurized pipes, ISO 9080 classifies the materials by internal pipe pressure tests. Based on such tests, the minimum required strength (MRS) to ensure pipe lifetimes of at least 50 years is determined and results in a classification of the materials as PE 63 (MRS=6,3 MPa), PE 80 (MRS=8,0 MPa) or PE 100 (MRS=10,0 MPa) [14]. The range in failure cycle numbers at a reference load was determined from 281215 cycles for the PE 80 up to 1.188.036 cycles for the PE 100 [15].…”

Section: Introductionmentioning

confidence: 99%

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Simulation Study of Fatigue Lifetime in PE100 Pipes

Medjadji¹,

Mazari²,

Kebir³

et al. 2019

JESA

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The fatigue lifetime predictions for semi-crystalline polymer, high density of polyethylene HDPE cases, is a new research problem, this work is focused on a simulation of the fatigue lifetime in PE100 pipes under internal pressure taking into account the influence of dimension parameters and internal pressures using the AFGROW software. Where, the developing numerical models gives an advantage of studying the problems more efficiently, since also very long-time processes can be simulated and analyzed in shorter times and different time frames of the process. The fracture m the service mechanics tools have been used to gain information on the resistance to crack growth. Furthermore, a fracture mechanics extrapolation procedure has been applied to predict the remaining fatigue lifetime of the pipes.

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“…As a result, the circumferential strength of the pipe made using traditional manufacturing methods is far lower than its axial strength, and it is difficult to satisfy the practical demand for higher circumferential strength of the thin-walled tube under hydrostatic pressure. Although there have been many reports in the research of polymer pipe [28,29,30,31,32,33,34,35,36,37,38,39,40,41,42], these studies have not been able to effectively realize the self-enhancement of the pipe’s circumferential strength without reducing its axial strength, especially the coincident self-enhancement of the pipe’s axial and circumferential strength.…”

Section: Introductionmentioning

confidence: 99%

The Structure and Performance of Short Glass Fiber/High-Density Polyethylene/Polypropylene Composite Pipes Extruded Using a Shearing–Drawing Compound Stress Field

2019

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Glass fiber reinforced polyolefin composite materials have many advantages regarding their performance and have been widely used in many fields. However, there are few reports on the simultaneously bidirectional self-enhancement of glass fiber reinforced polyethylene/polypropylene composite pipe. To self-reinforce the pipe’s circular and axial properties simultaneously, short glass fiber reinforced high-density polyethylene/polypropylene (SGF/HDPE/PP) pipes were extruded using a shearing–drawing two-dimensional compound stress field pipe-extrusion device. The effects of the rotating speed of the rotating shear sleeve on the orientation, heat behavior, microstructure, and tensile strength of the pipe were investigated in this paper. The microstructure was observed using scanning electron microscopy (SEM), and the crystal diffraction was analyzed using a polycrystalline X-ray diffractometer (WAXD), the heat behavior was measured using a differential scanning calorimeter (DSC), and the tensile strength was tested using a universal electronic tensile testing machine. The results showed that the shear induction effect induced by the shear rotating promoted the formation of the oriented structure of the crystal plate and SGFs along the circular and axial directions of the pipe simultaneously. Furthermore, it increased the crystallinity of the system, and self-improved the pipe’s circular and axial tensile strength at the same time.

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Determination of slow crack growth behaviour of polyethylene pressure pipes with cracked round bar test

Cited by 30 publications

References 14 publications

Accelerated testing method to estimate the long‐term hydrostatic strength of semi‐crystalline plastic pipes

Accelerated testing method to estimate the long‐term hydrostatic strength of semi‐crystalline plastic pipes

Simulation Study of Fatigue Lifetime in PE100 Pipes

The Structure and Performance of Short Glass Fiber/High-Density Polyethylene/Polypropylene Composite Pipes Extruded Using a Shearing–Drawing Compound Stress Field

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