Three-dimensional thermoelastic analysis of cracked plain weave glass/epoxy composites at cryogenic temperatures
ABSTRACT This paper examines the thermo-mechanical behavior of cracked G-11 woven glass/epoxy laminates with temperature-dependent material properties under tension at cryogenic temperatures. Three-dimensional finite elements are employed to model the architecture of the two-layer woven laminates. It is assumed that the cracks are confined to individual fiber bundles oriented transverse to the tensile load direction and span the thickness of the fiber bundles. The effects of residual thermal stresses caused by differences in the coefficients of thermal expansion of the composite constituents, and cracks on the mechanical behavior of two-layer G-11 woven laminates at cryogenic temperatures are explored. Numerical results for Young's modulus, Poisson's ratio, and stress distributions and concentrations are obtained and discussed in detail.
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ABSTRACT: The present paper deals with the problem of the micromechanics analysis of the elastic constants of a one-ply plain weave composite using the strain energy equivalency principle with the aid of the finite element method. By assuming undulation in one direction only the plain weave composite is modeled. A systematic treatment of the relationship between the semi-micromechanical aspects of the woven fabric structure and the macromechanical properties of the fabric composite is presented. The numerical estimation of the various elastic constants of a one-ply plain weave composite is given. A comparison of the resulting numerical prediction with experimental results shows that the method is valid and suggests that it should be extended to the case of a two-directional undulation model.Computers & Structures - COMPUT STRUCT. 01/1990; 36(5):839-844.
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ABSTRACT: A variational solution based on the principle of minimum complementary energy is presented for a damaged mosaic laminate model of woven fabric composites. Two damage modes, i.e. transverse yarn cracking and interface debonding, are considered. The stress components in the debonded segments of the laminate are obtained explicitly, while those in the perfectly bonded laminate segments are presented in terms of a perturbation function, which is governed by two fourth-order inhomogeneous ordinary differential equations. All possible expressions of this perturbation function are obtained in closed forms. The effective Young modulus and Poisson ratio of the damaged laminate are calculated using the determined stress field and the associated minimum complementary energy. Being applicable to the woven laminate in either the plane strain or the plane stress state, with the yarn materials either orthotropic or transversely isotropic, the current closed-form solution is very suitable for parametric studies. To demonstrate the application of the solution, a parametric study of some 176 sample cases is conducted using two different composite systems (i.e. glass fiber/epoxy and ceramic fiber/ceramic), four transverse yarn crack densities and eleven debonded lengths. The numerical results obtained here for the cases involving only the first damage mode (i.e. transverse yarn cracking) are identical with those reported in an earlier paper by Gao and Mall [Int J Solids Struct 38 (2001) 855]. When both the first and second damage modes are present, the sample calculations of this study quantitatively illustrate the effects of the two co-existing types of damage on the reduction in Young's modulus and Poisson's ratio of the damaged woven laminate.Composites Science and Technology 01/2002; 62(14):1821-1834. · 3.33 Impact Factor
- Journal of Engineering Materials and Technology-transactions of The Asme - J ENG MATER TECHNOL. 01/1994; 116(1).