Abstract: Spar is the main load-bearing component of the aircraft. In order to ensure its forming quality and production efficiency, it is necessary to adopt an automated forming method to manufacture the spar component. In this paper, the application and research status of the spar forming methods are introduced. According to the structural characteristics of large-size gradual section spar (>10 m long), the automatic fiber placement technology of composite spar is studied. Then, with the gantry-type automated fiber placement machine of M.TORRES as the laying platform, the key points of automatic fiber placement in spar are put forward. Furthermore, the trajectory planning method of the layup at different angles is determined. Combined with the trajectory planning, the optimization scheme of fiber placement for spar is proposed. Finally, the feasibility and correctness of the trajectory planning algorithm and the optimization scheme are verified by the manufacturing of the full-size composite spar using the automatic fiber placement, which provides a reference for the application of the automatic fiber placement technology in the forming of the large-size composite spar in China.

Key words: spar, composite material, automatic fiber placement, trajectory planning, manufacture