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Authors: Malcolm Lane, Alireza Forghani, Michael Andersen, Paulo Silva, Simon Hind, Drazen Djokic, Meysam Rahmat, Ali Yousefpour, Goran Fernlund, Anoush Poursartip

DOI: 10.33599/nasampe/s.23.0053

Abstract: Composite forming is an automated process used to shape prepreg laminates into complex geometries to improve laminate fit-up and reduce layup labour. During a forming process, the laminate experiences large deformations, and the prepreg pre-gelation behaviour exhibits highly non-linear temperature and rate dependency. In-plane and transverse shear, ply bending, ply/tow slip and separation, and tool-part interaction are among the key deformation mechanisms seen. Due to the viscoelastic/plastic nature of thermosetting prepreg behaviour, processing conditions significantly influence the laminate’s non-linear behaviour and lead to a complex interaction of properties which makes process optimization difficult. Process optimization can be conducted using modelling but requires appropriate test methods to characterize the necessary material properties. In this paper we present both a new framework and novel test methods to characterize tack and ply bending for forming processes. A complete characterization data set for a standard carbon fibre-epoxy prepreg over the full forming temperature range is also presented and is believed to be the first dataset of its kind to be presented in open literature.

References: [1] B. Liang, N. Hamila, M. Peillon, and P. Boisse, “Analysis of thermoplastic prepreg bending stiffness during manufacturing and of its influence on wrinkling simulations,” Composites Part A: Applied Science and Manufacturing, vol. 67, pp. 111–122, 2014. [2] A. Margossian, S. Bel, and R. Hinterhoelzl, “Bending characterisation of a molten unidirectional carbon fibre reinforced thermoplastic composite using a Dynamic Mechanical Analysis system,” Composites Part A: Applied science and manufacturing, vol. 77, pp. 154–163, 2015. [3] T. Martin, S. Mander, R. Dykes, and D. Bhattacharyya, “Bending of continuous fibre-reinforced thermoplastic sheets”, in Composite Materials Series, vol. 11, D. Bhattacharyya, Ed. Elsevier, pp. 371–401, 1997. [4] S. Ropers, “Bending behavior of thermoplastic composite sheets”, Wolfsburg Germany: Springer, 2017. [5] S. Ropers, M. Kardos, and T. A. Osswald, “A thermo-viscoelastic approach for the characterization and modeling of the bending behavior of thermoplastic composites,” Composites Part A: Applied Science and Manufacturing, vol. 90, pp. 22–32, 2016. [6] U. Sachs and R. Akkerman, “Viscoelastic bending model for continuous fiber-reinforced thermoplastic composites in melt,” Composites Part A: Applied Science and Manufacturing, vol. 100, pp. 333–341, doi:, 2017. [7] U. Sachs, “Friction and bending in thermoplasctic composites forming processes,” University of Twente, 2014. [8] H. Alshahrani and M. Hojjati, “A new test method for the characterization of the bending behavior of textile prepregs,” Composites Part A: Applied Science and Manufacturing, vol. 97, pp. 128–140, doi: 10.1016/j.compositesa.2017.02.027, 2017. [9] H. Behery and S. Kawabata, Eds., “The standardization and analysis of hand evaluation,” in Effect of mechanical and physical properties on fabric hand, Elsevier, 2005. [10] D. Budelmann, C. Schmidt, and D. Meiners, “Prepreg tack: A review of mechanisms, measurement, and manufacturing implication,” Polymer Composites, vol. 41, no. 9, pp. 3440–3458, 2020. [11] A. Gillanders, S. Kerr, and T. Martin, “Determination of prepreg tack,” International Journal of Adhesion and Adhesives, vol. 1, no. 3, pp. 125–134, 1981. [12] O. Dubois, J.-B. Le Cam, and A. Béakou, “Experimental Analysis of Prepreg Tack,” Exp Mech, vol. 50, no. 5, pp. 599–606, doi: 10.1007/s11340-009-9236-7, 2010. [13] C. Wohl et al., “Tack measurements of prepreg tape at variable temperature and humidity,” in CAMX Technical Conference, 2017. [14] R. J. Crossley, P. J. Schubel, and D. S. De Focatiis, “Time–temperature equivalence in the tack and dynamic stiffness of polymer prepreg and its application to automated composites manufacturing,” Composites Part A: Applied science and manufacturing, vol. 52, pp. 126–133, 2013. [15] A. Endruweit et al., “Characterisation of tack for uni-directional prepreg tape employing a continuous application-and-peel test method,” Composites Part A: Applied Science and Manufacturing, vol. 114, pp. 295–306, doi: 10.1016/j.compositesa, 2018. [16] ASTM D30 Committee, “Standard Test Method for Characterizing Tack of Prepregs Using a Continuous Application-and-Peel Procedure (ASTM D8336 - 21)”, doi: 10.1520/D8336-21, 2021. [17] A. Forghani et al., “Experimental Calibration of a Numerical Model of Prepreg Tack for Predicting AFP Process Related Defects,” in SAMPE 2018 Technical Conference and Exhibition, 2018.

Conference: SAMPE 2023

Publication Date: 2023/04/17

SKU: TP23-0000000053

Pages: 14

Price: $28.00

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