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Decoding the Dynamics of Thermoplastic Composite Pipes: Insights into Design

The Thermoplastic Composite Pipe, often referred to as CFTCP/RTP, boasts a dual-layered thermoplastic design, fortified with either fiberglass or carbon fiber for enhanced reinforcement. This piece aims to shed light on the nuances of the TCP's minimum bending radius, offering insights into optimal coiler design for the same.

Thermoplastic Composite Pipes: Insights into Design means, it's evident that it's a fully bonded composite pipe, characterized by its inner, reinforcement, and outer layers. Contrary to what one might assume, the TCP isn't as flexible as it appears. Instead, it stands as a robustly reinforced pipe. When subjected to deformation, the TCP predominantly experiences strain in its axial direction, rather than along the fiber's orientation. This behavior can be attributed to the manner in which fiberglass tapes envelop the liner pipe, resulting in what's termed as 'Twisted Bending'. This implies that the strain varies based on the fiber's direction, particularly its reinforcement layer orientation. Consequently, the design intricacies of the TCP play a pivotal role in determining its minimum bending radius. Any deviation below the prescribed Minimum Bending Radius (MBR) could compromise the fiberglass reinforcement layer's integrity.

Typically, fibers align with the TCP's axial trajectory, harmonizing with the fiber's hoop orientation to maintain a balanced pressure across fiber orientations. This alignment alternates between +55 and -55 degrees concerning the axial direction. Factors like the matrix material's bending rigidity influence the TCP's overall bending stiffness. For instance, the rigidity of a fiberglass tape isn't determined by individual fiber strands but by the tape as a whole. The inherent properties of thermoplastic polymers contribute to the diminished bending rigidity of CFTCP/RTP.

Delamination in TCP layers is often a consequence of excessive tensile stress from significant bending strains. Studies indicate that the minimum bending radius should surpass 14 times the TCP's external diameter.

In the context of risers, they predominantly follow the axial orientation. Given that risers are predominantly employed for oil transportation, they endure substantial pulling forces, resulting in pronounced strains along the fiber's direction. This makes fiber resilience a paramount consideration in TCP design. Research findings suggest that a fiber's tensile strength is approximately double its compressive strength. Hence, compression-induced fiber failures emerge as a primary concern during bending.

We cordially invite experts in the composite domain from across the globe to engage in a discourse with us on this subject.

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