Mechanical Performance of a Pressure Pipe CIPP Liner with Stress Concentration Effects Associated with Local Defects
In this study, continuum finite element modelling procedures are used to examine the mechanical response and performance of a cured in place pipe (CIPP) liner for pressure pipe. The external cast iron pipe and internal CIPP liner was modelled using three-dimensional brick (C3D8I) elements with multiple elements through thickness depending on the CIPP liner diameter to wall thickness (D/t) ratio. The modelling procedures were calibrated with available public domain data and the anisotropic material behaviour of the CIPP liner was established using tensile coupon tests data. A parameter study was conducted to assess mechanical performance of a pressure pipe CIPP liner with stress concentration effects due to local defects (e. g. wall voids). The sensitivity study investigated the CIPP liner outside diameter to CIPP wall thickness ratio (D/t), host pipe void diameter to host pipe inside diameter ratio (d/D), hoop stress due to internal pressure to yield stress ratio for the CIPP liner (σh/σy), and CIPP liner/host pipe interface friction coefficient (μ). Performance envelopes were developed that were consistent with current engineering practice and illustrated a class of parameters where an engineering condition assessment would be required to evaluate the CIPP liner performance. Material yield behaviour was observed for the higher liner dimension (D/t > 60) and hoop stress to yield ratios (σh/σy ≥ 0.6). The limit state can be governed by axial tension rather than ring tension when void ratios (d/D) are greater than 0.4. As the void ratio (d/D) increases, the hoop stress tends to behave as an unconstrained liner in the radial direction. The fully bonded interface has a distinct effect of reducing the axial, hoop, and effective stress.
|Conference||Pipelines 2019 Conference: Multidisciplinary Topics, Utility Engineering, and Surveying|
He, X. (Xiaoan), & Kenny, S. (2019). Mechanical Performance of a Pressure Pipe CIPP Liner with Stress Concentration Effects Associated with Local Defects. In Pipelines 2019: Multidisciplinary Topics, Utility Engineering, and Surveying - Proceedings of Sessions of the Pipelines 2019 Conference (pp. 515–527). doi:10.1061/9780784482506.054