Design Optimization & Analysis Validation of Complex Composite Parts Manufactured Using Fiber Patch Placement

Automated Fiber Placement (AFP) significantly improves production rates by minimizing interruptions and enhancing consistency, while also reducing part count, lead time, and production costs. Compared to traditional hand layup (HLU), AFP offers increased material efficiency. However, it also produces scrap due to leftover material in the creel and encounters difficulties when laying up highly contoured or small, complex parts. Fiber steering around intricate geometries often results in defects such as puckers (wrinkles on the inner radius of the tow) and overlaps. To address these limitations, Fiber Patch Placement (FPP)—a hybrid of additive manufacturing and fiber placement—is introduced. FPP enables the production of geometrically complex composites and curvilinear reinforcements by depositing small prepreg patches using a multi-robotic system. This approach offers greater flexibility in fiber deposition, allowing for the fabrication of intricate shapes at higher production rates than both AFP and HLU. First, the continuous-fiber part design is imported into patch design software to define the initial patch placement architecture, aligning reinforcement patches with expected load paths. A structural analysis is then performed, followed by iterative optimization to enhance performance and material efficiency. The optimized design is subsequently transferred to specialized software that generates the corresponding toolpaths and numerical control (NC) codes for robotic motion. Offline programming and simulation are used to virtually validate the layup process before physical production begins. By leveraging advanced robotics and digital manufacturing tools, FPP bridges the gap in producing complex composite geometries. This study outlines methodologies for the design and optimized manufacturing of FPP parts, including standard practices for patch modeling, integration of FPP-specific properties into finite element models, and established structural analysis workflows. Additionally, it details the performance of FPP composites through static and fatigue testing at the coupon level. Flat panels with varying patch overlap lengths were tested to evaluate strength reductions caused by fiber discontinuities and to support design optimization strategies. Building on prior findings from coupon-level tests and simulations, the validation was extended to a part-scale cylindrical specimen with a variable-radius compression profile. In both cases, test results closely aligned with analytical predictions, demonstrating the robustness of proposed design and analysis tools in supporting complex FPP design.