Development of hydro-axial tension method for whole pipe butt-fusion joint tensile test

Abstract

Assessing the integrity of the thermo-fusion joint in plastic pipes is important as they can appear as a weak link in the piping system. In this work, a hydro-axial tension (HAT) test was developed as a whole pipe axial tensile test and applied to evaluate the polyethylene (PE) pipe butt-fusion (BF) joint containing various flaws. HAT test utilizes hydrostatic pressure to cause axial tension in pipes. The experimental and numerical analysis was carried out to confirm the axial tensile stress as the dominant principal stress, causing axial tension in the pipe. The HAT method was further tested against the whole pipe mechanical axial tensile (AT) test, and the HAT was shown to closely duplicate the AT behavior of the whole pipe and the BF joint. In addition, the HAT test correctly identified PE pipe butt-fusions having no flaws and flawed joints containing cold-fusion and fine particulate contamination.

Keywords

• Polyethylene pipe
• Hydro-axial tension test
• Whole pipe axial tensile test
• Butt-fusion joint
• Cold fusion
• Fine particulate contamination