Toughness evaluation and durability analysis are two of the critical steps to design a toughened HDPE resin for durability in pipe applications. Durability analysis involves defect characterization, crack initiation and propagation mechanism, and long-term performance prediction. The methodology for durability analysis of high-density polyethylene (HDPE) pipe will be discussed in this paper. Various analytical techniques, such as fractography, hot-stage microscopy, energy-dispersive X-ray (EDX), microtransmittance infrared spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), have been used to characterize the defect properties and size distribution. Crack initiation and propagation mechanisms in HDPE have been analyzed by some accelerated tests and compared with that observed in the long-term hydrostatic pressure test. A new procedure for lifetime prediction of HDPE under creep is discussed based on the crack layer theory (Chudnovsky, A., 1984, NASA Contractor Report 174634). [S0094-9930(00)00802-7]

Issue Section:
Technical Papers
Keywords:
polymers, cracks, microscopy, fracture
Topics:
Durability, Fracture (Materials), Pipes, Creep, Microscopy
1.
Lang, R. W., Stern, A., and Doerner, G., 1996, “Applicability and Limitations of Current Lifetime Prediction Models for Thermoplastics Pipes Under Internal Pressure,” 8th Annual International Conference on Advances in the Stabilization and Degradation of Polymers, Switzerland.
2.
Scheirs
,
J.
, et al.,
1996
, “
PE100 Resins for Pipe Application
,”
Trends Polym. Sci.
4
, No.
12
, pp.
408
–
415
.
3.
ISO, 1994, “Thermoplastic Pipes for the Transport of Fluids—Methods of Extrapolation of Hydrostatic Stress Rupture Data to Determine the Long Term Hydrostatic Strength of Thermoplastic Pipe Materials,” ISO/TR 9080, International Organization for Standardization, Geneva, Switzerland.
4.
ISO, 1995, “Thermoplastic Pipes for the Conveyance of Fluids—Determination of the Resistance to Rapid Crack Propagation—Small Scale Steady State (s4),” Draft International standard DIS 13477, International Organization for Standardization, Geneva, Switzerland.
5.
Lang
,
R. W.
,
Stern
,
A.
, and
Doerner
,
G.
,
1997
, “
Applicability and Limitations of Current Lifetime Predication Models for Thermoplastics Pipes Under Internal Pressure
,”
Angew. Makromol. Chem.
,
247
, pp.
131
–
145
.
6.
Sehanobish
,
K.
et al.,
1985
, “
Fractographic Analysis of Field Failure in Polyethylene Pipe
,”
J. Mater. Sci. Lett.
,
4
, pp.
890
–
894
.
7.
Kadota
,
K.
, and
Chudnovsky
,
A.
,
1992
, “
Constitutive Equations of Crack Layer Growth
,”
Polym. Eng. Sci.
32
,
1097
1097
.
8.
Chudnovsky
,
A.
,
Shulkin
,
Y.
,
Baron
,
D.
, and
Lin
,
K. P.
,
1995
, “
New Method of Lifetime Predication for Brittle Fracture of Polyethylene
,”
J. Appl. Polym. Sci.
56
, pp.
1465
–
1478
.
9.
Lu
,
X.
,
Qian
,
R.
, and
Brown
,
N.
,
1991
, “
Discontinuous Crack Growth in Polyethylene Under a Constant Load
,”
J. Mater, Sci.
26
, p.
917
917
.
10.
Hertzberg, R. W., and Manson, J. A. 1980, Fatigue of Engineering Plastics, Academic Press, New York, NY.
Copyright © 2000
 by ASME
You do not currently have access to this content.