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Session: Session 9: Modelling and Characterisation of AFP
Session starts: Thursday 16 April, 10:50
Presentation starts: 11:50
Room: Main

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Amir Hafez Yas ()
Mehdi Hojjati ()

Abstract:
Automated Fiber Placement (AFP) has advanced composite manufacturing to a higher level of automation by enabling the production of large and geometrically complex structures with high repeatability and reduced waste. However, the fabrication of thermoset composites using this method is highly dependent on process parameters such as compaction pressure, contact width, and temperature, which must be precisely controlled to ensure consistent laminate quality. Insufficient bonding between layers can result in the formation of defects such as tape folding, bridging, and wrinkles. When manufacturing on complex moulds with concave or convex geometries, process parameters can vary significantly due to changes in surface curvature and roller conformity. This study aims to minimize the alteration of process parameters during AFP layup over curved molds by varying the stiffness of the compaction roller along its length through modifications to its shaft. In the first stage, finite element (FEM) simulations were conducted to determine the optimal shaft dimensions and depth levels for concave and convex mould configurations, enabling the roller to maintain uniform pressure under various curvature conditions. Based on the numerical results, polyurethane rollers with corresponding shaft geometries were manufactured to experimentally validate the numerical predictions. Pressure-sensitive films were employed to capture the pressure distribution over flat, concave, and convex surfaces, and the results were compared against the FEM outcomes. The findings demonstrate that adjusting roller stiffness by the design of its shaft geometry, pressure uniformity, and formability of the roller can be enhanced. This study highlights the crucial role of compaction roller stiffness on its formability over complex moulds and how certain designs can provide better uniformity of pressure distribution and formability of the roller.