A method is presented for predicting the distribution of orientation of rigid short fibers in thin compression molded parts. The method extends Folgar and Tucker's model for fiber orientation in a concentrated suspension to the case of spatially non-uniform flows and orientation states. A generalized Hele-Shaw model is used to predict flow and defor mation during mold filling. Other assumptions are appropriate for sheet molding com pound : fibers much longer than the part thickness and a cold material molded in a hot mold. The predictions compare favorably to experiments on sheet molding compound and on a model suspension of nylon monofilaments in silicone oil.
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References
1.
Goettler, L.A., "Flow Orientation of Short Fibers in Transfer Molding," Proc. , 25th Ann. Tech. Conf., SPI RP/C Div., Sec. 14-A (1970).
2.
Bell, J.P., "Flow Orientation of Short Fiber Composites," J. Compos. Mat., Vol. 3, p. 244 (1969).
3.
Bright, P.F. , Crowson, R.J. and Folkes, M.J., "A Study of the Effect of Injection Speed of Fibre Orientation in Simple Mouldings of Short Glass Fibre-Filled Polypropylene ," J. Mat. Sci., Vol 13, p. 2497 (1978).
4.
Owen, M.J., Thomas, D.H. and Found, M.S., "Flow, Fibre Orientation and Mechanical Properties Relationships in Polyester DMC," Proc. , 33rd Ann. Tech. Conf, SPI RP/C Div., Sect. 20-B (1978).
5.
Taggart, D.G. and Pipes, R.B., "Processing Induced Fiber Orientations in Transfer and Injection Molding," Report No. 12, Center for Composite Materials, U. of Delaware , Newark, Delaware (1979).
6.
Jeffery, G.B. , "The Motion of Ellipsoidal Particles Immersed in a Viscous Fluid," Proc. Roy. Soc., A102, p. 161 (1922 ).
7.
Givler, R.C. , Crochet, M.J. and Pipes, R.B., "Numerical Prediction of Fiber Orientation in Dilute Suspensions," J. Compos. Mat., Vol. 17, pp. 330-343 (1983).
8.
Givler, R.C. , "A Numerical Technique for the Prediction of Short Fiber Orientation Resulting from the Suspension Flow," Transport Phenomena in Material Processing, M. M. Chen, J. Mazumdar and C. L. Tucker , eds., pp. 99-103, ASME, New York (1983).
9.
Folgar, F.P. and Tucker, C.L., "Orientation Behavior of Fibers in Concentrated Suspensions," J. Reinf Plast. Compos., Vol. 3, pp. 98-119 (1984).
10.
Jackson, W.C., Folgar, F. and Tucker, C.L., "Prediction and Control of Fiber Orientation in Molded Parts," Polymer Blends and Composites in Multiphase Systems, C. D. Han, ed., Adv. Chem. Ser. No. 206, p. 279, ACS, Washington (1984).
11.
Barone, M.R. and Caulk, D. "Kinematics of Flow of SMC," Polymer. Compos., Vol. 6, pp. 105-109 (1985).
12.
Lee, C.C. and Tucker, C.L., "Simulation of Nonisothermal Compression Molding," SPE Tech. Pap., Vol. 29, pp. 740-742 (1983).
13.
Lee, C.C., Folgar, F. and Tucker, C.L., "Simulation of Compression Molding for Fiber Reinforced Thermosetting Polymers," J. Engr. Industry, Vol. 106, pp. 114-125 (1984).
14.
Denton, D.L. , "Effects of Processing Variables on the Mechanical Properties of Structural SMC-R Composites," Proc., 36th Ann. Tech. Conf ., SPI RP/C Div., Sect. 16-A (1981).
15.
Tucker, C.L. and Folgar, F., "A Model of Compression Mold Filling ," Polymer Eng. Sci., Vol. 23, pp. 69-73 (1983).
16.
Osswald, T.A. and Tucker, C.L., "An Automated Simulation of Compression Mold Filling for Complex Parts," SPE Tech. Pap. , Vol. 31, pp. 169-172 (1985).
17.
Jackson, W.C. , "A Method of Predicting Fiber Orientation in Compression Molded Parts," Master of Science Thesis, University of Illinois atUrbana-Champaign ( 1983).
18.
Lee, C.C., "Numerical Models for Compression Mold Filling," Ph.D. Thesis, University of Illinois at Urbana-Champaign ( 1984).
19.
Loubignac, G., Cantm, G. and Touzot, G., "Continuous Stress Fields in Fimte Element Analysis," AIAA J., Vol. 15, pp. 1645-1647 (1977).
Chen, C.Y. and Tucker, C.L., "Mechanical Property Predictions for Short Fiber/Brittle Matrix Composites ," J. Reinf. Plastics Compos., Vol. 3, pp. 120-129 (1984).
22.
Bird, R.B., Armstrong, R.C., Hassager, O. and Curtiss, C.F., "Dynamics of Polymeric Liquids: Kinetic Theory," Vol. 2, John Wiley and Sons, New York (1977).
23.
Jackson, W.C. and Tucker, C.L., "Predicting Fiber Orientation in Compression Molded Parts," SPE Tech. Pap., Vol. 29, pp. 751-753 (1983).
24.
Folkes, M.J. and Russell, D.A.M., "Orientation Effects During the Flow of Short Fibre Reinforced Thermoplastics," Polymer , Vol. 21, pp. 1252-1258 (1980).
25.
Folgar, F. , "Fiber Orientation Distributions in Concentrated Suspensions: A Predictive Model," Ph.D. Thesis, University of Illinois at Urbana-Champaign (1983).
26.
Advani, S.G. and Tucker, C.L., "A Tensor Description of Fiber Orientation in Short Fiber Composites," SPE Tech. Pap., Vol. 31, pp. 1113-1118 (1985).
27.
Lovrich, M.L. and Tucker, C.L., 'Automated Measurement of Fiber Orientation in Short Fiber Composites," SPE Tech. Pap., Vol. 31, pp. 1119-1122 (1985).
