Stress measurements in single-crystal and polycrystalline alumina are revisited
using a recently developed optical fluorescence energy shift method. The method
simultaneously utilizes the R1 and R2 Cr-related ruby line shifts in alumina to
determine two components of the stress tensor in crystallographic coordinates,
independent of the intended or assumed stress state. Measurements from a range of
experimental conditions, including high-pressure, shock, quasi-static, and bulk
polycrystals containing thermal expansion anisotropy effects, are analyzed. In many
cases, the new analysis suggests stress states and stress magnitudes significantly
different from those inferred previously, particularly for shock experiments. An
implication is that atomistic models relating stress state to fluorescence shift
require significant refinement for use in materials-based residual stress
distribution analyses. Conversely, the earliest measurements of fluorescence in
polycrystalline alumina are shown to be consistent with recent detailed measurements
of stress equilibrium and dispersion.
Corrigendum to “Frequency energy shift method for bearing fault prognosis using microphone sensor” [Mech. Syst. Signal Process. 147 (2021) 107068]
