Flexure Behavior of Composite Spoolable Tubes

Abstract

Composite tubes are a realistic alternative to metals in many offshore applications, offering high specific stiffness and strength as well as tailorability to sustain environmental loads [1]. Furthermore the manufacturing options that are available enable them to be coiled onto spools for ease of storage, handling, and ease of installation. Some current applications of inland spoolable composite tubulars include buried and above ground flowlines, pipeline relining applications, and downhole injection strings [2]. Our objective is to develop a synergistic methodology that integrates testing and computational modeling to identify the minimum spool radius for storage without introducing damage in the composite tube. Four-point flexure tests are conducted to simulate the spooling conditions. The computational models are based on the two dimensional shell elements of ABAQUS finite element package. These models incorporate non-linear geometry effects as well as a user material subroutine with residual stresses to predict damage progression. Parametric studies are conducted to assess the effects of lay-up, geometry, and constitutive material on the flexural behavior of the composite tubes and compared with the experimental data.