Numerical Assessment on the Mechanical Performance of Pressure Pipe CIPP Liner with Local Defects in the Outer Host Pipe

In this study, the three-dimensional continuum finite element analysis was conducted to assess the effects of local defects in the host pipe on the mechanical performance of the CIPP liner subject to internal pressure, axial deformation and flexure loading conditions.For a CIPP liner subject to internal pressure with local circular void defects in the host pipe, the limit state was governed by axial tension when the defect diameter to CIPP diameter (d/D) ratio was greater than 0.4. The effects of a circumferential gap defect were evaluated. For internal pressure loading, the longitudinal distribution of normalized radial displacement for the CIPP liner was primarily influenced by the width of the circumferential gap defect width to CIPP liner diameter (g/D) and the CIPP D/t ratio. For internal pressure and pipe rotation loading, the defect gap ratio (g/D) had an impact on the CIPP liner deformation pattern.