Development of Notched Ring Test for Measuring Slow Crack Growth

Author(s) : Jörg Wermelinger, Sunwoong Choi

In the development of an international standard on non-destructive test for polyethylene electrofusion socket (EF) joints, the inspection capability of the phased array ultrasonic test (PAUT) in assessing flaws in the joints was needed to establish procedure qualification of the test method. For this, a worldwide...

Author(s) : Sunwoong Choi, Tom Marti

Small scale, steady state (S4) testing per ISO 13477 is a lab-based procedure to determine the critical pressure at which a fracture will propagate following initiation in a given pipe material filled with a given test medium. The S4 test was originally developed for the natural gas industry using air as the test...

Author(s) : Sooho Pyo, Junghyun Nam, Yoonsang Kim and Sunwoong Choi

The Notched Ring Test (NRT) has been recently developed to measure slow crack growth (SCG) in plastics pipes and fittings. The NRT specimen in the form of a notched full ring is directly obtained from the extruded pipe or injection molded fitting and has demonstrated its effectiveness in generating slow crack growth...

Author(s) : Edwards, Broutman, Choi

The Alternate Methods Committee of the Plastics Pipe Institute’s Hydrostatic Stress Board (HSB) has completed development of an alternate method for determining the hydrostatic design basis (HDB) for plastic piping materials. The initial work was reported at Plastic Pipes X, in Sweden in 1998.1 An ASTM test method has...

Author(s) : Choi, Lee, Broutman, Edwards, Palermo, Cho, Choi, Park

In recently designated plane strain grooved tensile (PSGT) methodology of ASTM F2018 standard, a groove in the direction perpendicular to the loading axis allows biaxial stress state to be generated under a uniaxial loading. The biaxial stress state produced very closely approximates the internally pressurized pipes...

Author(s) : Broutman, Edwards, Shah, Palermo

The Alternate Methods Committee of the Plastics Pipe Institute's Hydrostatic Stress Board (HSB) has initiated development of an alternate method for determining the hydrostatic design basis (HDB) for plastic piping materials. After reviewing several test methods, the plane-strain tensile method, developed by Choi and...

Author(s) : Choi

A plane strain specimen has been developed which creates a biaxial stress state when loaded in uniaxial tension. A detailed stress analysis of this specimen is presented. The stress state was generated though the use of a groove across the width of the specimen. Both theoretical and experimental results are presented....

Author(s) : Duvall, Nylander, Broutman

Thermoplastic gas distribution piping has been utilized in the United States for over 25 years. However, there is little data available on how such materials age in a service environment and how such aging might affect future performance. In this program, polyethylene pipe samples that were removed from actual gas...

Author(s) : Mutter & Benjamin

Fig, 1 gives the last known figures (1-1-73) of materials used in the Dutch gas network at 8 bar and lower (under supervision of the gas boards). The figure shows that during the last 18 years more than 20,000 km of uPVC pipes have been laid, and that since 1966 about 3,200 km of high impact PVC have been applied. The...

Author(s) : Choi

Author(s) : Pyo