Described are novel composite structural panels and methods of forming such panels. In some examples, a method comprises wrapping a mandrel with a composite tape to form a composite tube. This wrapping operation allows forming composite tubular structures with any cross-sectional profiles defined by the mandrel. The wrapping is also used to control the fiber orientations in the composite tubular structures. The composite tube is then cut into composite tubular structures. In some examples, the composite tube is partially cured prior to the cutting, which allows removal of the mandrel while preserving the shape of the composite tube. This cutting operation allows forming composite tubular structures with different lengths, shapes, and orientations of the ends. The composite tubular structures are disposed on a support structure and are bonded to each other. In some examples, this bonding operation also involves final curing of the composite tubular structures.

Described are novel composite structural panels and methods of forming such panels. In some examples, a method comprises wrapping a mandrel with a composite tape to form a composite tube. This wrapping operation allows forming composite tubular structures with any cross-sectional profiles defined by the mandrel. The wrapping is also used to control the fiber orientations in the composite tubular structures. The composite tube is then cut into composite tubular structures. In some examples, the composite tube is partially cured prior to the cutting, which allows removal of the mandrel while preserving the shape of the composite tube. This cutting operation allows forming composite tubular structures with different lengths, shapes, and orientations of the ends. The composite tubular structures are disposed on a support structure and are bonded to each other. In some examples, this bonding operation also involves final curing of the composite tubular structures.

A method for producing a medium includes forming a fiber assembly by discharging a raw material liquid of fibers from a nozzle to generate the fibers and depositing the fibers so as to surround a circumferential surface of a rotatable winder, and transferring the fiber assembly to a base member while rotating the rotatable winder. The circumferential surface of the rotatable winder has a plurality of belt-shaped projection portions extending in a direction along a rotation axis of the rotatable winder.

A method for producing a medium includes forming a fiber assembly by discharging a raw material liquid of fibers from a nozzle to generate the fibers and depositing the fibers so as to surround a circumferential surface of a rotatable winder, and transferring the fiber assembly to a base member while rotating the rotatable winder. The circumferential surface of the rotatable winder has a plurality of belt-shaped projection portions extending in a direction along a rotation axis of the rotatable winder.