Research On Automated Fiber Placement Technology Of Composite Wing Spar

Automated fiber placement is a composite material automated processing technology developedfrom automated tape laying and filament winding, which is widely used in the manufacture of aircraftprimary structure. With the need of large aircraft development of our country, this paper do theresearch for the automated fiber placement technology of composite wing spar. The main contents asfollows:In order to check the stiffness of automated fiber placement mould of a large aircraft wing spar,the mould’s force model during placement process was established, and the theoretical calculationmethod and finite element analysis method for the force-deformation of mould were also investigated.An error compensation method was proposed to improve placement precision.In order to improve the quality of part fabricated by automated fiber placement, this paperanalyzed the influence of processing parameters, including placement temperature, speed, and press,on the part’s mechanical property through single-factor experiments. The results showed that theinterlaminar shear strength was improved as the placement temperature increased, but theimprovement of the interlaminar shear strength with the increase in temperature was observed up to acertain limit, beyond which, a further increase in temperature decreased the interlaminar shearstrength. The interlaminar shear strength was decreased as the placement speed was accelerated. Theinterlaminar shear strength is improved as the placement press increased, but the improvement of theinterlaminar shear strength with increasing in press also had a limit, beyond which, a further increasein press decreased the interlaminar shear strength. Then through response surface method, the optimalprocess parameters was aquired. The optimal comprehensive mechanical property of parts were bestat36℃placement temperature,50mm/s placement speed, and180N placement force.For the large aircraf wing spar model, a path planning algorithm for automated fiber placementwas proposed, and the corresponding relationship between fiber number and placement path was alsoestablished. The path planning and post processing software were developed by Visual C++6.0, theinformation of the trajectory points and machining codes of45°,-45°,0°and90°path of the wing sparwere obtained through the software. Then did the practical placement and curing to get the finalproduct. An automated fiber placement method for laying a band of fibers on convex surface orsurface with edge is proposed to improve the laying quality of wing spar.