Application of Finite Element Method for Designing Flexible and Anisotropic Pipe Liners

This paper introduces a novel design approach based on finite element analysis (FEA) for flexible and anisotropic liners, specifically aimed at large-diameter pipelines and the retrofitting of non-circular conduits. The objective is to enhance flow conditions and reduce sedimentation, particularly in combined sewer systems. The FEA model is versatile, also applicable to point repair systems for hazardous fluid transmission lines. Overcoming challenges in composite material applications, the proposed model is validated through laboratory testing and comparison with existing methods, demonstrating robust correlations. It is successfully applied in designing FRP liners for a 17.5-ft sewer interceptor and a carbon fiber-based point repair system for underwater oil pipelines. The FEA model proves effective for trenchless structural rehabilitation, addressing complexities in anisotropic and flexible liner applications for point repair, large-diameter pipelines, and non-circular conduits.