Mechanical engineer, General Electric Corporate Research & Development, Schenectady, NY
Analytical models are presented and used to explore the mechanics of transversely loaded, high-temperature composites with a thermally induced residual stress field and a vanishingly weak fiber-matrix interface strength. Of specific interest in this investigation is the existence of a distinctive, bilinear characteristic of the transverse stress-strain curve for composites of moderate fiber-volume fractions in which the coefficient of thermal expansion of the matrix is larger than the fiber and the interface strength is vanishingly weak. For such a system, it is found that the “knee” in the predicted transverse stress-strain curve separating the two linear response zones is associated with the load at which compressive residual stresses at the interface are overcome and separation of the matrix and fiber occurs. Before this “knee,” the transverse modulus of the “weak interface” model is predicted to be the same as for a well-bonded system. The effects of fiber and matrix properties, interface friction, and fiber-volume content are examined.
Paper ID: CTR10181J