Anomalous Strain Behaviour under Stress Controlled Loading of CFCCs

摘要

Recent investigations on the mechanical response of continuous fibre reinforced ceramic matrix composites (CFCCs) have clearly indicated the effect of axial residual stress relief caused by progressive interfacial debonding during loading. Under certain conditions this stress relief can give rise to negative strain accumulation during monotonic tensile loading. Interfacial debonding also occurs under cyclic loading and the associated relief of axial residual stresses may cause a deceleration of or even a reversal in the direction of strain accumulation. This clearly gives rise to a "positive" fatigue effect. However, the opposite can also occur, in which case accelerated fatigue failure is observed. Examples of both cases and the conditions under which they occur are presented.