Title: Overmolding Technology Applied for Structural Aeronautical Applications

Authors: Gilles Andrieu

DOI: 10.33599/nasampe/c.19.0634

Abstract: In the frame of ARCHES thermoplastic structure box, STELIA Aerospace has decided to develop and integrate on a full scale realistic and typical airframe demonstrator 6 thermoplastic technological bricks: AFP automatic fiber placement of thermoplastic slit tape, automatic fiber placement of Lightning Strike Protection, dynamic robotic induction welding of TP stringers, hybrid TP structure by over-molding short fiber and long fiber, fast stamping of stringers and frames and Out Of Autoclave consolidation. This technical paper will focus on PEKK Thermoplastic over-molded technology. The objective is to evaluate high performance PEKK matrix compound, joints quality between long fiber and short fiber and performance for aircraft applications. The overmolding process is clearly an asset of thermoplastic technology. This hybrid TP technology provides light and economical efficient 3D composite parts for low cost high production rate able to replace classical 3D metallic machined parts preventing corrosion issues inside composite fuselages. The first objective of this project was to propose different kind of disruptive integrated design principles. The second target was to evaluate this technology in terms of performance and cost. The third aims to optimize the mechanical performance of joints by identifying the key parameters and perform experimental tests. To achieve these objectives, STELIA AEROSPACE has developed two kinds of overmolded architectures. One of them is based on a flat organo-sheet plate to demonstrate the capability for adding different functions in a one shot process at a high volume rate (stiffening function, opening function, integrating sealing and metallic inserts to hold system parts). a test campaign On these parts was performed to optimize mechanical strength with a pull-off test plan. Main parameters were identified and set-up to optimize mechanical strength. Another important point is size limitation of sur-injected components which could be a show stopper to implement this technology widely on aircraft structures. For this reason STELIA Aerospace developed in this project a special tooling to implement this technology on large typical parts. Frames have been chosen for this demonstration. On these parts, the objective was to functionalize frames with the addition of brackets. A second demonstration has hence been carried out and will be presented.

During this project, Arkema 8010CA30 PEKK compound material was used. To evaluate the manufacturing process ability and robustness, samples have been analyzed to conclude about material health. Micro cuts, DSC have been extracted to check porosity, waviness and cristallinity of PEKK resin. In the same way, tensile tests have been performed on overmolded brackets. In addition to that a 3 points bending test campaign has been performed to give us stress values to implement them in our stress numerical models.

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Conference: CAMX 2019

Publication Date: 2019/09/23

SKU: TP19-0634

Pages: 19

Price: $38.00