Analysis of fibre wrinkling during squeezing flows of fibre-reinforced composites
- 94 Downloads
Abstract
An analysis of the stability of squeezing flows between flat plates (consolidation flows) of viscous liquids reinforced by continuous fibres is presented. The ideal linear fibre-reinforced fluid model is used to model the composite as an incompressible Newtonian fluid reinforced with inextensible fibres. The development of small fibre wrinkles initially present in the preimpregnated plies is analysed using linear stability theory. It is shown that when the flows are lubricated by resin rich layers, two perturbation modes are possible. In the first mode, the wrinkles are of the same form throughout the thickness of the sample while in the second mode they vary linearly with distance from the platens. In both cases the stability depends on the normal components of the applied stress. If the only traction acting in addition to hydrostatic pressure is that due to the squeezing force then the first perturbation mode is stable. This prediction is in agreement with experimental results.
Keywords
Hydrostatic Pressure Applied Stress Flat Plate Linear Stability Normal ComponentPreview
Unable to display preview. Download preview PDF.
References
- 1.R.J. Silva-Nieto, B.C. Fischer and A.W. Bailey, Predicting mold flow for unsaturated polyester sheet molding compounds. Polymer Composities 1 (1980) 14–23.Google Scholar
- 2.C.C. Lee, F. Folgar and C.L. Tucker, Simulation of compression molding for fibre-reinforced thermosetting polymers. J. Eng. Indus. 106 (1984) 114–125.Google Scholar
- 3.M.R. Barone and D.A. Caulk, A model for the flow of a chopped fibre reinforced polymer compound in compression molding. J. Appl. Mech. 53 (1986) 361–371.Google Scholar
- 4.R. Balasubramanyam, R.S. Jones and A.B. Wheeler, Modelling transverse flows of reinforced thermoplastic materials. Composites 20 (1989) 28–32.Google Scholar
- 5.T.G. Rogers, Squeezing flow of fibre-reinforced viscous fluids. J. Eng. Math. 23 (1989) 81–89.Google Scholar
- 6.T.G. Rogers, Shear characterisation and inelastic deformation of fibre-reinforced materials. In G.J. Dvorak (ed), Inelastic Deformation of Composite Materials pp. 653–674. New York: Springer-Verlag (1991).Google Scholar
- 7.A.J.M. Spencer, Deformations of Fibre-reinforced Materials. Oxford: Clarendon Press (1972).Google Scholar
- 8.C.M. O'Bradaigh and R.B. Pipes, A punch deformation experiment for sheet forming of thermoplastic materials, Proc. of the Third International Conference on Automated Composites (I.C.A.C. 91), Netherlands Conference Centre, The Hague, 15–17 October, (1991).Google Scholar
- 9.M.R. Wisnom, The effect of the fibre misalignment on the compressive strength of unidirectional carbon fibre/epoxy. Composites 21 (1990) pp. 403–407.Google Scholar
- 10.B.D. Hull, T.G. Rogers and A.J.M. Spencer, Theory of fibre buckling and wrinkling in shear flows of fibre-reinforced materials. Composites Manufacturing 2 (1992) 185–191.Google Scholar
- 11.B.D. Hull, T.G. Rogers and A.J.M. Spencer, A linear stability analysis of flows of transversely isotropic non-Newtonian fluids. J. non-Newtonian Fluid Mech. 43 (1992) 325–349.Google Scholar
- 12.F.N. Cogswell, The processing science of thermoplastic structural composites. Int. Polymer Proc. 1 (1987) 157–165.Google Scholar
- 13.D.J. Groves, D.M. Stocks and A.M. Bellamy, Isotropic and anisotropic shear flow in continuous fibre th thermoplastic composites. In D.R. Oliver (ed), Proceedings of the Third European Rheology Conference pp. 190–193. Elsevier (1990).Google Scholar
- 14.R.B. Pipes, J.W.S. Hearle, A.J. Beaossart and A.M. Sastry, A constitutive relation for the viscous flow of an oriented fiber assembly. J. Composite Materials 25 (1991) 1204–1217.Google Scholar
- 15.A. Mittleman and I. Roman, Tensile properties of real unidirectional Kevlar/epoxy composites. Composites 21 (1990) 63–69.Google Scholar
- 16.R.S. Jones and R.W. Roberts, Ply re-orientation in compression. Composites Manufacturing 2 (1992) 259–266.Google Scholar