Void growth and resin transport during processing of thermosetting — Matrix composites
The fabrication of composite laminates having a thermosetting resin matrix is a complex process. It involves simultaneous heat, mass, and momentum transfer along with chemical reaction in a multiphase system with time-dependent material properties and boundary conditions. Two critical problems, which arise during production of thick structural laminates, are the occurrence of severely detrimental voids and gradients in resin concentration. In order to efficiently manufacture quality parts, on-line control and process optimization are necessary, which in turn require a realistic model of the entire process. In this article we review current progress toward developing accurate void and resin flow portions of this overall process model.
Void stability as a function of temperature and pressure is first considered at equilibrium as a bounding behavior for the actual cure cycles. If sufficient moisture is present in the resin, notably high void pressures are possible. Next, the time-dependent stability and growth of voids containing pure water vapor and air/water mixtures is described for a typical commercial curing cycle. The resin pressure early in the cycle and the initial resin moisture content are critical considerations in producing a void-free laminate. A pressure-temperature-humidity stability map is described which identifies conditions for void growth or dissolution throughout the cure cycle.
A generalized 3-dimensional resin flow model is summarized, which employs soil mechanics consolidation theory to predict profiles of resin pressure, resin flow velocity, laminate consolidation, and resin content in a curing laminate.
KeywordsVoid Growth Epoxy Resin Composite Cure Cycle Resin Flow Resin Viscosity
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- 1.Hinrichs, R. J.: “Processing Science of Epoxy Resin Composites”, Industry Contract Review F33615-80-C-5021, General Dynamics Convair Division, San Diego, CA, 19, 1982.Google Scholar
- 2.Kardos, J. L., Duduković, M. P., McKague, E. L. and Lehman, W. M.: Composite Materials: Quality Assurance and Processing, ASTM-STP 797, C. E. Brwoning, Ed., American Society for Testing and Materials, 1983, pp. 96–109.Google Scholar
- 3.May, C. L., Ed.: Chemorheology of Thermosetting Polymers, ACS Symposium Series, No. 227, American Chemical Society, Washington, DC, 1983.Google Scholar
- 4.Kingery, W. D.: Introduction to Ceramics, New York: Wiley 1960, Ch. 10, p. 291.Google Scholar
- 5.Epstein, P. S., and Plesset, M. S.: J. Chem. Phys., 18, 1505 (1950).Google Scholar
- 6.Scriven, L. E.: Chem. Eng. Sci., 10, 1 (1959).Google Scholar
- 7.Bankoff, S. G.: Advances in Chemical Engineering, 6, New York: Academic Press 1966.Google Scholar
- 8.Ready, D. E., and Cooper, A. R., Jr.: Chem. Eng. Sci., 21, 916 (1966).Google Scholar
- 9.Duda, J. L., and Vrentas, J. S.: AIChE J., 15, 351 (1969).Google Scholar
- 10.Subramanian, R. S., and Weinberg, M. C.: J. Chem. Phys., 72, 6811 (1980).Google Scholar
- 11.Tao, L. N.: J. Chem. Phys., 69, 4189 (1978).Google Scholar
- 12.Tao, L. N.: J. Chem. Phys., 71, 3455 (1979).Google Scholar
- 13.Interim Report, “Processing Science of Epoxy Resin Composites”, Contract No. F33615-80-C-5021, 9/15/80-10/15/81, Air Force Materials Laboratory, Wright Patterson AFB, OH 45433.Google Scholar
- 14.Brown, G. G., and McKague, E. L.: “Processing Science of Epoxy Resin Composites”, 8th Quarterly Technical Report, Contract No. F33615-80-C-5021, Air Force Materials Laboratory, Wright-Patterson AFB, OH 45433, August 1982.Google Scholar
- 15.Loos, A. C., and Springer, G. S.: J. Comp. Mats., 17, 135 (1983).Google Scholar
- 16.Williams, J., Donnellan, T., and Trabocco, R.: paper presented at 16th National SAMPE Tech. Conf., Albuquerque, Oct. (1984).Google Scholar
- 17.Gutowski, T. G.: SAMPE Quarterly, July (1985), p. 58.Google Scholar
- 18.Lindt, J. T.: SAMPE Quarterly, Oct. (1982), p. 14Google Scholar
- 19.Brand, R. A., and McKague, E. L.: “Processing Science of Epoxy Resin Composites”, Tenth Quarterly Report, Contract No. F33615-80-C-5021, Air Force Materials Lab., Wright-Patterson AFB, OH 45433, May (1983).Google Scholar
- 20.Computer Aided Curing of Composites, McDonnell Douglas Corp., 4th Interim Report, Contract No. F33615-83-C-5088, Air Force Materials Laboratory, Wright-Patterson AFB, OH 45433, April, 1985.Google Scholar
- 21.Dave, R., Kardos, J. L., and Duduković, M. P.: “A Mathematical Model for Resin Flow During Composite Processing”, submitted to Polymer lomp.Google Scholar
- 22.Terzaghi, K.: Theoretical Soil Mechanics, New York: John Wiley 1943.Google Scholar
- 23.Taylor, D. W.: Fundamentals of Soil Mechanics, New York: John Wiley 1948.Google Scholar