Abstract
This study is focused on the analysis of micro-perforated prepregs created from standard, off the shelf prepregs modified by a particular laser process to enhance ductility of prepregs for better formability and drapability. Fibres are shortened through the use of laser cutting in a predetermined pattern intended to maintain alignment, and therefore mechanical properties, yet increase ductility at the working temperature. The increase in ductility allows the product to be more effectively optimised for specific forming techniques. Tensile tests were conducted on several specimens in order to understand the ductility enhancement offered by this process with different micro-perforation patterns over standard prepregs. Furthermore, the effects of forming temperature was also analysed to assess the applicability of this material to hot draping techniques and other heated processes.
References
Neoh, E.-T.: Drape Properties of Thermosetting Prepregs. Massachusetts Institute of Technology, MSc Mechanical Engineering (1992)
Ford, R.A.: Thermo-ductile composites: new materials for 21st century manufacturing - micro-perforated thermoplastic composites. Mater. Des. 22, 177–183 (2001). Elsevier
Edwards, H E, Parratt, N.J., Potter, K.D.: Synthesis and Applications of Aligned, Discontinuous Composites, pp. 975–993. Metallurgical Society of AIME. 2nd International Conference on Composite Materials, Toronto (1978)
Dogu, I.: The mechanics of stretch breaking. Textil. Res. J. 42, 419–426 (1972)
Pepin Associates, Inc.: DiscoTex: Pepin Associates, Inc. Pepin Associates, Inc Web Site.
Hansen, N.W.: US 6,477,740 B1 United States of America, 12 November. Assignee: Hexcel Corporation (2002)
ACG Ltd. Technical Report - ACG DForm - Components. Advanced Composites Group Web Site. [Online]
Ford, R., Griffiths, B.: The Creation of Ductile, Composite Prepregs, with Close to UD Properties. SAMPE, 40th ISTC, Memphis (2008)
Friedrich, K., Schuster, J.: Modeling of the mechanical properties of discontinuous-aligned-fiber composites after thermoforming. Compos. Sci. Tech. 57, 405–413 (1997). Elsevier
Patel, J.M.: Low velocity impact testing of new generation composite laminates: the effects of a micro-perforation treatment. University of Bath, Final Year Project (2009)
ASTM International: ASTM D3039 Standard test method for tensile properties of polymer matrix composite materials. s.l.: ASTM International (2008)
Campbell, F.C.: Manufacturing Technology for Aerospace Structural Materials. Elsevier, London (2006)
Hexcel Composites Ltd.: HexPly® Prepregs for Aerospace - M21 Datasheet. Hexcel Composites Ltd Website. [Online] (2011)
Clyne, T.W., Matthams, T.J.: Mechanical properties of long fibre thermoplastic composites with laser drilled microperforations. 1. Effect of perforations in consolidated material. 2. Effect of prior plastic strain. Compos. Sci. Tech. 59, 1,169–1,187 (1999). Elsevier
Loos, A.C., Davé, R.S.: Processing of Composites (Progress in Polymer Processing). Carl Hanser Verlag GmbH & Co, Munich (1999)
Voisey, K.T., et al.: Fibre swelling during laser drilling of carbon fibre composites. Optic. Laser. Eng. 44, 1, 185–1, 197 (2006)
Acknowledgements
The authors appreciate the support by Integrated Materials Technology Ltd. (IMT) for providing the samples.