Fibre Composites: Mesomechanics and Mesostructures
Mesomechanics deals with mechanics at a level between micromechanics and structural mechanics. It takes into account the heterogeneous nature of the material which sometimes leads to unexpected property variations which could not be predicted directly from micromechanical considerations. In addition, in the composites themselves, a mesostructure can be observed, as well as a microstructure. A typical example of this is the fibre waviness that occurs in individual laminae in a laminate. This waviness can be evaluated for any layer in a laminate, by cutting the composite at a small angle to the fibre direction in that layer, and measuring the ellipticity of the fibre sections where they intersect the plane of the cut. It has been found that four varieties of carbon reinforced PEEK prepreg give four different patterns of fibre deviations. These deviations correlate well with the compressive strengths of the layers: the bigger the deviation, the less the compressive strength. Thus a mesomechanical/mesostructural theory can be developed for compressive strength. A similar approach can be used to evaluate other mesostructure-property relations. However, mesostructures first need to be identified, classified, and quantified. A system of four main classes is proposed and discussed here. The eventual aim is to use our knowledge of mesostructures to develop processing – property relations.
KeywordsMechanics structure Mechanical properties Processing-Structure-Property Relationships
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- 1.J.E. Ashton, T.C. Halpin, and P.H. Petit, Primer on Composite Materials: Analysis (Technomic Pub., Co., Stamford, CT 1969), Chp. 1.Google Scholar
- 3.R.M. Jones, Mechanics of Composite Materials, (McGraw Hill, New York, 1975), Chp. 4.Google Scholar
- 6.Engineered Materials Handbook 1 Composites, (ASM International, Metals Park OH., Ed. C.A. Dostal, 1987), 376.Google Scholar
- 7.A. Mrse and M.R. Piggott, Proc. 35th SAMPE Symp., 2236, (1990).Google Scholar
- 8.P.W.K. Lam and M.R. Piggott, ASTM STP 1110, (1991) in press.Google Scholar
- 9.D.V. Rosato, Handbook of Fiberglass and Advanced Plastic Composites, (Van Nostrand Reinhold, New York, 1969, Ed. G. Lubin), p. 140.Google Scholar
- 10.W.H. Sutton and J. Chorne, Fibre Composite Materials, Amer. Soc. for Metals, Metals Park OH., S.H. Bush, Ed., 1965), Chpt. 9, p. 189.Google Scholar
- 12.J.G. Davies, ASTM STP 580, 364, (1975).Google Scholar
- 13.A.L. Highsmith, J.J. Davies, and K.L.E. Helms, ASTM STP (1991) in press.Google Scholar
- 16.A. Mrse and M.R. Piggott, 1st International Conference on Deformation and Fracture of Composites Manchester, U.K., 1991), paper #8.Google Scholar