Thermal expansion characteristics of coated fiber composites

Analyses of composite structures require a variety of material properties. These properties can be obtained experimentally by subjecting the laminate to axial, shear, transverse and thermal loading. Although it is possible to determine the properties of the laminate in the axial direction, it is extremely difficult to do so in the transverse direction. An alternate approach is to use analytical methods using constitutive properties of the composites. One of these methods is the finite element method. The finite element approach can be used to predict the transverse mechanical properties of composites because the geometry, arrangement of fibers in the matrix and the individual properties of the fiber can be conveniently described. For ceramic composites thermal and hygroscopic effects are very significant therefore the thermal behavior of the composite needs to be investigated. The first step in this is to predict the coefficients of thermal expansion. A three-dimensional hexagonal array model is used to study the transverse thermal properties of unidirectional composites with coated fibers using a hexagonal array as a repeating structural unit.