2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference


Title
Nonlinear Behavior of a Medium Density Polyethylene Pipe Material


Author(s)
Mr. Suprio Das, Memorial University of Newfoundland (Presenter)
Dr. Ashutosh Dhar, Memorial University of Newfoundland
Mr. Abu Hena Muntakim, Memorial University of Newfoundland
Abstract

Nonlinear Behavior of a Medium Density Polyethylene Pipe Material

Suprio Das, Ashutosh Sutra Dhar and Abu Hena Muntakim

Department of Civil Engineering – Memorial University of Newfoundland, St. John’s, NL, Canada

Abstract: Medium density polyethylene (MDPE) pipes are extensively used for gas distribution system in Canada and worldwide.  MDPE pipe material possesses time-dependent behavior that governs the performance of the pipes buried in the soil. However, very limited information is currently available in the literature on the time-dependent behavior of MDPE pipe materials. In this research, an extensive laboratory investigation is carried out to investigate the time-dependent behavior of MDPE pipe material. Uniaxial tensile tests are conducted with samples (coupons) cut from the wall of a 60 mm diameter MDPE pipe using waterjet. A surface planer has been used to remove the curvature. The coupon samples cut from the pipe might experience residual stresses during sample preparation, which might affect the test results. To investigate the effect of the residual stresses, tensile tests with samples of full cross-section of the pipe are also conducted. Tests are conducted at various strain rates to capture the effects of rates of loading. The experimental results are used to develop numerical modelling approach of time-dependent material behavior using a commercially available software, Abaqus.  The strain-rate dependent material behavior of MDPE is incorporated in Abaqus through development of USDFLD subroutine. The proposed model successfully simulates the test results of the MDPE pipe. Temperature effects on the mechanical behavior of MDPE pipe were not considered.

Keywords: Polymer pipe, Medium density Polyethylene, Strain rate, Time-dependent model, Uniaxial Strain.