Manufacture and Characterization of a Variable Stiffness, Unitized, Integrated-stiffener
Thermoplastic Wingbox
D. Peeters, G. Clancy, V. Oliveri, G. Zucco, R. Telford, A.K. Bandaru, M. Rouhi, R. O’Higgins,
T.M. Young, P.M. Weaver
University of Limerick, Limerick, Ireland

Abstract:
The use of composite materials in the aerospace industry has increased significantly over the last 25 years. To highlight the potential of thermoplastic materials to produce large structures in an out-of-autoclave (OOA) process, a variable stiffness, unitized, integrated-stiffener thermoplastic wingbox has been designed, manufactured and characterised at the University of Limerick. A novel combination of winding and laserassisted tape placement (LATP) in-situ consolidation was used to manufacture the wingbox demonstrator. Representative specimens were used to assess local structural performance. Interlaminar shear strength and the mode I and II fracture toughness testing of the skin-stiffener interface showed that good bonding was achieved. Geometrical analysis and a novel wedge peel test showed that steered fibres, which lead to a variable stiffness structure, bonded well. Finally, 4-point bend testing of corner samples showed that corner regions of good quality can be achieved by winding in combination with LATP. These results indicate that high-quality OOA structures can be produced by winding in combination with LATP.