Hoopsrigid

Hoopsrigid is a term used in structural engineering to describe a class of circular-frame assemblies in which a series of hoops are connected by rigid joints to form a stiff, load-bearing ring lattice. The concept emphasizes maintaining near-constant circular geometry under applied loads, reducing deformation compared with more flexible hoop constructions. Hoopsrigid frames are used in contexts where a lightweight, open, circular support is desirable, such as architectural canopies, aerospace mounting rings, and industrial equipment housings.

Construction and design: A hoopsrigid assembly consists of evenly spaced circular hoops made from slender tubes or composite channels, joined at the joints by rigid gussets or welds that resist rotation. The joints are treated to ensure high moment transfer, enabling the frame to behave as a single, continuous ring under bending and axial loads. Designers select hoop diameter, wall thickness, and joint rigidity to balance stiffness, weight, and manufacturability.

Materials and manufacturing: Common materials include aluminum alloys, carbon-fiber composites, and short steel sections. Fabrication methods include welding, bolted gusset connections, or adhesive-bonded joints, with coatings chosen for corrosion resistance and environmental exposure.

Performance and applications: Compared with flexible circular frames, hoopsrigid structures offer improved torsional stiffness and shape retention, at the cost of higher fabrication complexity. They are suitable for lightweight ring supports, radome or satellite mounting rings, instrument enclosures, and artistic installations where a rigid circular silhouette is desired.

See also: rigid-frame structures, hoop stress, geodesic domes.