Evaluations of residual axial stresses and interfacial friction in Nicalon fibre-reinforced macro-defect-free cement composites

Abstract

The residual axial stress and the interfacial frictional stress of Nicalon fibre-reinforced macro-defect-free cement composites have been evaluated using the indentation technique. In these composites, both the residual axial stress in the fibre and the interfacial bonding are relatively high compared to other ceramic composites. Owing to the high residual axial stress, Poisson's effect can be ignored in analysing the stress-displacement relation of the fibre, and the interfacial frictional stress along the sliding length can be assumed to be a constant during indentation loading and unloading. Because of the strong interfacial bonding, consideration of the upper bound of the sliding zone length during unloading is essential. The sliding zone length during unloading is limited by the debond length at peak loading. The theoretical predictions of stress-displacement relations are in excellent agreement with the experimental results.