Residual Stress-Related Common Intersection Points in the Mechanical Behavior of Ceramic Matrix Composites Undergoing Cyclic Loading

摘要

The mechanical response of SiC-fiber reinforced barium osumilite ceramic matrix composites tested in tension with unloading/reloading cycles was very recently reported to exhibit self-assembling common intersection points (CIP) of unloading/reloading loops in the tensile domain which relate exactly to the thermal residual stress state of reinforcing fibers in a matrix of a lower coefficient of thermal expansion (Dassios et al. Compos A: Appl Sci Manuf44:105-113, 2013). Knowledge of the experimentallyexact residual stress state enables, herein, examination of the validity of the conventional compliance-based methodology for indirectly calculating residual stresses from projected/extrapolated CIPs. The efficiency of two prominent residual stress prediction models is also tested across the experimentally-established value of thermal residual stress (TRS). The significance of the CIP as the TRS-free origin of the stress-strain curve is discussed in view of the importance in calculating accurate material property values from mechanical testing data of materials under residual stress.