Manufacturing Demonstration of an All-Composite Selectively 3D Stitched Fuselage Section using HMZ-RTM

The next generation of aerospace structures is increasingly reliant on multifunctional, unitized composite designs that reduce part count, weight, and manufacturing complexity. This study presents the manufacturing demonstration of a stiffened, highly-unitized fuselage panel using a novel Heated Mold Z-Flow Assisted Resin Transfer Molding (HMZ-RTM) process. The selected architecture features an all-composite construction with integrated hat-stiffeners and two oval window cutouts, mimicking transport-class fuselage sections while emphasizing manufacturability and structural efficiency. Selective through-thickness stitching is employed to improve delamination resistance. This work addresses long-standing challenges associated with resin infiltration in thick, unitized architectures by utilizing localized mold heating and 3D resin extraction pathways to promote through-thickness flow. A complete bag-side HMZ-RTM layup strategy was implemented to ensure full compaction and reliable permeability management during infusion. The resulting structure demonstrates the manufacturability, robustness, and scalability of HMZ-RTM for large, unitized, damage-tolerant airframe components and provides a path forward for certifiable, damage-tolerant fuselage components manufactured through a single-shot infusion strategy. The details of tool design, preform construction, stitching procedures, and infusion methodologies are described in the paper.