Effects of Defect Size on Crush Test Load of Butt Fusion Welded MDPE Pipes

Tun, Nwe Ni;Lai, Huan Sheng;Jeon, Gyu Min;Yoon, Kee Bong;Kil, Seong Hee

  • 투고 : 2015.11.08
  • 심사 : 2015.12.10
  • 발행 : 2015.12.31


It is expected that the size of welding defect affects the mechanical performance of welded medium density polyethylene (MDPE) pipe joints. In this study, butt fusion welded MDPE pipe joints with a single spherical or planar defect of various sizes were studied using experimental crush testing and also by finite element method. The crush test showed that the mechanical performance of crush was not affected by the size and geometry of a single welding defect when the defect size was increased to 45% of the pipe's wall thickness. The simulation results indicated that the effect of the single welding defect on the Von Mises stress distribution near the defect explained the reason of the test results.


MDPE;Polyethylene;Welding defect;Crush test


  1. Leskovics, K., Kollar, M. and Barczy, P.: "A study of structure and mechanical properties of welded joints in polyethylene pipes", Materials Science and Engineering: A, vol. 419, 138-143, (2006)
  2. Kil, S. H., Jo, Y. D. and Yoon, K. B.: "The case study of phase array ultrasonic for polyethylene pipeline in the electrofusion joints", in Proceedings of the 12th International Conference on Pressure Vessel Technology, Jeju, South Korea, (2009)
  3. Lee, B. Y., Kim, J. S., Lee, S. Y. and Kim, Y. K.: "Butt-welding technology for double walled polyethylene pipe", Materials and Design, vol. 35, 626-632, (2012)
  4. Stokes, V. K.: "Experiments on the hot-tool welding of three dissimilar thermoplastics", Polymer, vol. 39(12), 2469-2477, (1998)
  5. Stokes, V. K.: "The vibration and hot-tool welding of polyamides", Polymer Engineering and Science, vol. 41(8), 1427-1439, (2001)
  6. Riahi, M., Kooshayan, K. and Ghanati, M. F.: "Analysis of effect of pressure and heat on mechanical characteristics of butt fusion welding of polyethylene pipes", Polymer-Plastics Technology and Engineering, vol. 50, 907-915, (2011)
  7. Ezrin, M.: Plastic failure guide-cause and prevention, Munich, Hanser, (1996)
  8. Barker, M. B., Bowman, J. and Bevis, M.: "Fatigue properties of high density polyethylene pipe systems", Journal of Materials Science, vol. 15, 265-268, (1980)
  9. DVS 2202-1: "Imperfections in thermoplastic welded joints-Features, description, evaluation", (2008)
  10. Lai, H. S., Kil, S. H. and Yoon, K. B.: "Effects of defect size on failure of butt fusion welded MDPE pipe under tension", Journal of Mechanical Science and Technology, vol. 29(5), 1973-1980, (2015)
  11. Lai, H.S., Tun, N. N., Kil, S. H. and Yoon, K. B.: "The effects of defects on the burst failure of butt fusion welded polyethylene pipe", Journal of Mechanical Science and Technology, under review, (2015).
  12. Chen, H., Scavuzzo, R. J. and Srivatsan, T. S.: "Influence of joining on the fatigue and fracture behavior of high density polyethylene pipe", Journal of Materials Engineering and Performance, vol. 6(4), 473-480, (1997)
  13. ISO 21307: "Plastics pipes and fittings-butt fusion jointing procedures for polyethylene (PE) pipes and fittings used in the construction of gas and water distribution systems", (2011)
  14. Lai, H.S., Kil, S. H. and Yoon, K. B.: "A study on proper location of welding defect in three point bend testing with MDPE pipe", Journal of Energy Engineering, vol. 24(1), 1-9, (2015)


연구 과제 주관 기관 : KETEP, KIAT