Composite spoolable tube

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS Composite fibers (graphite, Kevlar, fiberglass, boron, etc.
) have numerous assets including high strength, high stiffness, light-weight, etc.
, however, the stress strain response of composite fibers is linear to failure and therefore non ductile.
Composite coiled tubing must therefore address the strain limitations in another manner, i.
e.
, by providing a construction to meet the requirements with a near elastic response or with large deformations of the matrix.
Such a composite arrangement must have high resistance to bending stresses and internal pressure and external pressure.
It must also have high axial stiffness, high tensile and compressive strength and be resistant to shear stress.
All of these properties are combined in the composite tubular member of the invention to provide a coiled tubing which can be bent to a radius compatible with winding onto a reasonable size spool.
P.
K.
Mallick in the text book entitled Fiber-Reinforced Composites Materials manufacturing and Design, defines a composite in the following manner: "Fiber-reinforced composite materials consist of fibers of high strength and modulus embedded in or bonded to a matrix with distinct interfaces (boundary) between them.
In general, fibers are the principal load-carrying member, while the surrounding matrix keeps them in the desired location and orientation, acts as a load transfer medium between them, and protects them from environmental damages due to elevated temperatures and humidity, for example".
This definition defines composites as used in this invention with the fibers selected from a variety of available materials including carbon, aramid, and glass and the matrix or resin selected from a variety of available materials including thermoset resin such as epoxy and vinyl ester or thermoplastic resins such as polyetheretherketone (PEEK), polyetherketoneketone (PEKK), nylon, etc.
Composite structures are capable of carrying a variety of loads in combination or independently, including tension, compression, pressure, bending, and torsion