Hierarchical Orthogrid–Stiffened Cylinder: Improved Manufacturing and Load Carrying Ability

ABSTRACT Adopting filament winding and co‐curing technique, carbon fiber–reinforced composite (CFRC) cylinder with hierarchical orthogrid stiffeners was designed and manufactured. The cylinder has two‐level orthogrid stiffeners. The primary stiffeners strengthen the integral rigidity while the sub‐stiffeners strengthen the local rigidity of the skin. In compression, the cylinder fails at 480 kN and the failure is controlled by the local buckling of the skin. Currently, most research utilizes manual winding, which is cost‐effective but results in poor preparation quality. The remaining studies employ machine winding with metal molds, achieving high preparation quality but at a higher cost. Most research struggles to establish a manufacturing balance between low cost and high performance. For most wet‐winding work, the fiber volume fraction of ribs can hardly reach 50% due to poor intersection handling, inaccurate fiber bundle material usage, and fiber tension control. In this paper, the machine winding method combined with a rubber mold is employed to balance preparation quality and cost. The manufacturing process has been improved through automated filament winding, vacuum‐bag loading, and node‐chamfering treatment. These improvements effectively control fiber tension, ensure a high fiber volume fraction (~60%), and reduce stress concentration, respectively. The load‐carrying capacity of the cylinder is greatly improved, and it indicates that this hierarchical‐stiffened cylinder is a good selection for large‐diameter aerospace cylindrical shells.