Buckling collapse of HDPE liners: Experimental set-up and FEM simulations

Abstract

The purpose of this work is to provide a more complete framework for the development of short-term thermoplastic models to improve the design of liners subjected to external pressure. A device to perform short-term physical collapse buckling tests on HDPE liners to emulate in-service behavior under controlled conditions was designed and constructed. Tests were performed to explore the effect of temperature (in the range of 0–60 °C) on the buckling parameters of a HDPE pipe confined in a steel host pipe. The constitutive model for this material was calibrated from compression and tensile tests, performed at various strain rates and temperatures. The Three Network viscoplastic material constitutive model was adopted to reproduce material behavior. Full 3D FEM simulations of collapse buckling tests were conducted and validated against experimental data. Once the 3D full FE model was verified a simplified 2D model was generated to perform an intensive parametric study considering many temperatures and pipe aspect ratios. With data arising from the parametric study a predictive Glock’s type function was derived, which takes into account the effect of temperature and the viscoplastic constitutive behavior of HDPE.