Schapery

Viscoelastic characteristics of composite materials usually result from a viscoelastic-matrix material such as epoxy resin. General stress analysis of viscoelastic composites was discussed by Schapery [6-54]. An important application to laminated plates was made by Sims [6-55]. 

R. A. Schapery, Stress Analysis of Viscoelastic Composite Materials, in Composite Materials Workshop, S. W. Tsai, J. C. Hatpin, and Nicholas J. Pagano (Editors), St Louis, Missouri, 13-21 July 1967, Technomic, Westport, Connecticut, 1968, pp. 153-192. Also Journal of Composite Materials, July 1967, pp. 228-267. 

Alexander, R.M., Schapery, R.A., Jerina, K.L. and Sander, B.A. (1982). Fracture Characterization of a random fiber composite material. In Short Fiber Reinforced Composite Materials. ASTM STP 722 (B.A. Sanders cd.), ASTM, Philadelphia, PA, pp. 208-224. 

Three-dimensional distributions of the micro-residual stresses are very complicated, and are affected by the elastic properties, local geometry and distribution of the composite constituents within a ply. Many analytical (Daniel and Durelli, 1962 Schapery, 1968 Harris, 1978 Chapman et ah, 1990 Bowles and Griffin, 1991a, b Sideridis, 1994) and experimental (Marloff and Daniel, 1969 Koufopoulos and Theocaris, 1969 Barnes et ah, 1991 Barnes and Byerly, 1994) studies have been performed on residual thermal stresses, A two-dimensional photoelastic study identified that the sign and level of the residual stresses are not uniform within the composite, but are largely dependent on the location (Koufopoulos and Theocaris,... 

Schapery, R.A. (1968). Thermal expansion coefficients of composite materials based on energy principles. J. Composite Mater. 2, 380-404. 

The quasielastic method as developed by Schapery [26] is used in the development of the viscoelastic residual stress model. The use of the quasielastic method is motivated by the fact that the relaxation moduli are required in the viscoelastic analysis of residual stresses, whereas the experimental characterization of composite materials is usually in terms of the creep compliances. An excellent account of the development of the quasielastic method is given in [27]. The underlying restriction in the application of the quasielastic method is that the compliance response of the material shows little curvature when plotted versus log time [28]. Harper [27] shows excellent agreement between the quasielastic method and direct inversion for AS4/3510-6 graphite/epoxy composite. For most graphite/thermoset systems, the restrictions imposed by the quasielastic method are satisfied. 

Schapery, R. A., Solid Rocket Structural Integrity Abstr. Ill (4) (Oct. 

Pickett, D, E. Saylak, D. Lytton, R L. Conger, W E. Newcomb, De Schapery, R k. "Extension and Replacement of Asphalt Cement with Sulfur " Report FHWA-RD-78-96,... 

There is strong interest to analytically describe the fzme-dependence of polymer creep in order to extrapolate the deformation behaviour into otherwise inaccessible time-ranges. Several empirical and thermo-dynamical models have been proposed, such as the Andrade or Findley Potential equation [47,48] or the classical linear and non-linear visco-elastic theories ([36,37,49-51]). In the linear viscoelastic range Findley [48] and Schapery [49] successfully represent the (primary) creep compliance D(t) by a potential equation ... 

R. A. Schapery, On the Characterization of Nonlinear Viscoelastic Materials, Polymer Engineering and Science, 9, 295-310 (1969). 

Schapery, R. A. "Texas A M University Report MM 3724-81-1" College Station, Texas, 1981. 

Schapery, R. A. Composite Materials. Proc. Japan-U.S. Conf. 1981, Tokyo, Japan, p. 163. 

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