Experimental investigation and damage simulation of large-scaled filament wound composite pipes

This paper investigates the progressive collapse of filament wound Toray T700/Epotech X4201 composite pipes with various layups via a combined experimental and numerical study. The experimental program examines the flexural behavior of full-diameter T700/X4201 pipes under four-point bending and the tensile behavior of filament wound coupon specimens cut from the pipes. The tests show that the composite layup significantly influences the deformation, flexural resistance, and failure mechanisms of the composite pipes. The CFRP pipe with the optimal complex layup [(90/+/- 15/90/+/- 45(3))(5)/+/- 45(3)] design has higher ultimate resistance in bending than other designs with layups of [+/- 45)(28) and [90](56). Coupon tests show similar effects of composite layup on the tensile behavior of coupon specimens. The numerical effort evolves a three-dimensional progressive damage model to predict the failure in the CFRP coupons and pipes. The damage model incorporates a nonlinear in-plane shear behavior of the T700/X4201 composite material prior to damage initiation and uses a continuum damage mechanics approach to model the matrix and fiber damage progression in the composite pipes. The combined experimental-numerical work provides a more complete understanding of the bending behavior of large-scaled composite pipes, showing distinct failure modes for filament wound pipes with different layups. The load-displacement curves, ultimate bending resistance and failure modes of the composite pipes with different layups are accurately captured using the proposed damage model, demonstrating the capability for the failure analysis of large-scaled composite pipes such as composite risers in offshore applications.