Lifetime prediction of polyethylene pipe based on cyclic load

doi:10.19491/j.issn.1001-9278.2022.09.010

Abstract

Abstract:

In this paper， a cyclic loading circular bar （CRB） test was conducted to measure the corresponding relationship between the crack growth rate da/dt and stress factor K_I of three types of PE materials A， B and C at loading ratios of R=0.1， 0.3 and 0.5， respectively. Through using the theory of linear elastic fracture mechanics of polymer materials in the condition by extrapolating to R=1 （static load）， the failure time t_f of PE pipes with defects was obtained. The results were compared with those obtained form full notch creep test （FNCT）. When there was an initial crack defect at a_ini=0.4 mm on the inner wall of the three PE pipes， the failure lifetimes of extrapolated tubes obtained from the CRB test were 44， 53 and 65 years for the PE pipe A， B and C， respectively. The extrapolating results of FNCT were 53， 59 and 79 years for the PE pipe A， B and C， respectively. The test results indicated that the lifetime prediction results of CRB and FNCT had a good positive correlation， and their deviation was small. The experimental results confirmed the availability of the method.

Key words: polyethylene pipe, cyclic loading crack round bar test, full notch creep test, lifetime prediction

CLC Number:

TQ320.7

YANG Bo, YANG Zhen, ZENG Chen, WANG Zhigang, ZHAI Wei, CAO Fuxiang. Lifetime prediction of polyethylene pipe based on cyclic load[J]. China Plastics, 2022, 36(9): 63-69.

Figures/Tables 12

Fig.1. The schematic diagram of pipe crack growth rate curve under static load

Fig.2. The schematic diagram of CRB test［7］

Fig.3. The schematic diagram of creep crack dynamics curve under static loading when being extrapolated to R=1.0［5］

Fig.4. CRB cross⁃section of material B with R=0.1 at different Kmax

Fig.5. Relationship between Nf and Kmax of the three kinds of PE materials with R=0.1

Fig.6. Corresponding curves between da/dt and Kmax of three kinds of PE materials notched samples under different R

管材编号	A	m
A	3.05×10^-6	7.083
B	4.67×10^-7	7.050
C	1.95×10^-7	6.388

Tab.1. Intrinsic parameters A and m corresponding to three kinds of PE materials

Fig.7. The tf⁃COD curves of the three kinds of material notched samples at different temperatures

Fig.8. The d（COD） /dt⁃T cures of the three kinds of material notched samples

管材编号	T/℃	F/MPa	$d C O D / d t$ /mm $∙ h - 1$	A	m
A	23	8.5	7.84×10^-4	6.40×10^-8	4
B	23	8.5	2.83×10^-4	2.42×10^-8	4
C	23	8.5	2.15×10^-4	1.84×10^-8	4

管材编号	T/℃	F/MPa	$d C O D / d t$ /mm $∙ h - 1$	A	m
A	23	8.5	7.84×10^-4	6.40×10^-8	4
B	23	8.5	2.83×10^-4	2.42×10^-8	4
C	23	8.5	2.15×10^-4	1.84×10^-8	4

Tab.2. The intrinsic parameters A and m corresponding to three kinds of PE materials

Fig.9. The pipe model with initial crack defects［16］

Fig.10. The σhoop⁃tf relation curves of three kinds of PE materials

References 16

1	施建峰，胡安琪，郑津洋. 聚乙烯管材标准发展现状分析［J］. 中国塑料， 2021， 35（3）：112⁃123.
	SHI J F， HU A Q， ZHENG J Y. Development status of technical standards in polyethylene piping［J］.China Plastics， 2021， 35（3）：112⁃123.
2	：Polyethylene （PE） materials for piping systems⁃determination of resistance to slow crack growth under cyclic loading⁃ cracked round bar test method ［S］. Switzerland： International Organization for Standardization， ISO， 2015.
3	Frank A， Pinter G. Evaluation of the applicability of the cracked round bar test as standardized PE⁃pipe ranking tool［J］ Polymer Testing， 2014，33： 161⁃171.
4	翟伟，杨波，李茂东，等. 聚乙烯管材耐慢速裂纹增长性能的快速评价的研究现状［J］. 高分子材料科学与工程， 2018， 34（11）： 175⁃182.
	ZHAI W， YANG B， LI M D，et al. Tests for slow crack growth failure in polyethylene pipes［J］. Polymer Materials Science & Engineering， 2018， 34（11）： 175⁃182.
5	杨波，刘一江，李茂东，等.基于循环载荷的聚乙烯管材裂纹圆棒试验方法研究进展［J］.中国塑料，2019，33（10）：128⁃136.
	YANG B， LIU Y J， LI M D，et al. Research progress in cyclic crack round bar test for polyethylene pipes［J］. China Plastics，2019，33（10）：128⁃136.
6	杨波，左晓锋，王志刚，等.聚乙烯材料耐慢速裂纹扩展性能与微观结构相关性研究进展［J］.中国塑料，2019，33（11）：91⁃98.
	YANG B， ZUO X F， WANG Z G，et al. Research progress in relationship between resistance of slow crack growth and microstructure of polyethylene［J］. China Plastics， 2019，33（11）：91⁃98.
7	杨波，何嘉平，翟伟，等.基于循环载荷法评价聚乙烯管材性能的可靠性研究［J］.中国塑料，2020，34（3）：54⁃61.
	YANG B， HE J P， ZHAI W，et al. Evaluation of performance reliability for polyethylene pipe by cyclic loading method［J］. China Plastics， 2020，34（3）：54⁃61.
8	Frank A， Redhead A， Kratichvilla T， et al. Accelerated material ranking with cyclic CRB tests ［C］//Plastics Pipes XIV， Barcelona， Spain， 2012.
9	Frank A， Berger I J， Arbeiter F， et al. Lifetime prediction of PE100 and PE100⁃RC pipes based on slow crack growth resistance ［C］//Plastic Pipes Conference PPXVIII， Berlin， Germany， 2016.
10	Technical Committee ISO/TC 61， Plastics， Subcommittee ： Plastics⁃determination of environmental stress cracking（ESC） of polyethylene—full⁃notch creep test （FNCT）［S］.Switzerland： International Standard，2019.
11	中华人民共和国国家质量监督检验检疫总局，中国国家标准化管理委员会. 塑料聚乙烯环境应力开裂（ESC）的测定全缺口蠕变试验（FNCT）［S］.北京：中国标准出版社，2016.
12	Beech S H， Clutton E Q. Interpretation of results of full notch creep test and comparison with notched pipe test ［J］. Plastics， Rubber and Composites， 2005， 34（7）： 294⁃300.
13	Nezbedová E， Pinter G， Frank A， et al. Accelerated tests for lifetime prediction of PE⁃HD pipe grades ［J］. Macromolecular Symposia， 2017， 373（1）： 1600096.
14	王志刚，杨波，李仕平，等. 含缺陷聚乙烯管材蠕变损伤行为及使用寿命预测方法研究［J］. 塑料工业， 2020， 48（11）： 90⁃93.
	WANG Z G， YANG B， LI S P，et al. Research on creep damage behavior and lifetime estimation method of defects PE pipes［J］. China Plastics Industry， 2020， 48（11）： 90⁃93.
15	杨波，左晓锋，王志刚，等. 基于微观结构相关性的聚乙烯全缺口蠕变试验［J］. 塑料， 2022， 51（2）： 123⁃145.
	YANG B， ZUO X F， WANG Z G，et al. Full notch creep test of polyethylene based on microstructure correlation［J］.Plastics， 2022， 51（2）： 123⁃145.
16	Hutař P， ŠevčÍK M， NÁHlÍK L， et al. A numerical methodology for lifetime estimation of HDPE pressure pipes［J］. Engineering fracture mechanics， 2011， 78（17）： 3 049⁃3 058.

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[2]	SHI Jianfeng, HU Anqi, ZHENG Jinyang. Development Status of Technical Standards in Polyethylene Piping [J]. China Plastics, 2021, 35(3): 112-123.
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