Development of composite coaxial cylinder stress analysis model and its application to SIC monofilament systems

An analytical model is presented allowing prediction of the principal stresses in a system composed of a set of coaxial cylinders, subject to temperature change or applied stress. The materials must exhibit transverse isotropy of stiffness and thermal expansivity. The model represents a development of an analysis published by Mikata and Taya, the modification allowing any number of component cylinders and a finite outer radius. Use of the model is illustrated by means of a series of examples involving SiC monofilaments. Application to the behaviour of composites containing many aligned fibres is demonstrated, using cylinder radii appropriate for the fibre volume fraction in the composite. It is shown by comparison with predictions from an Eshelby model that this is an acceptable approximation, preferable to the surrounding of fibre and matrix by an outer composite layer of infinite radius.