Stress sensing performance using mechanoluminescence of SrAl₂O₄:Eu (SAOE) and SrAl₂O₄:Eu, Dy (SAOED) under mechanical loadings

In this paper, the stress sensing performance of two well-known mechanoluminescence (ML) sensing materials, (1) SrAl2O4:Eu (SAOE) and (2) SrAl2O4:Eu, Dy (SAOED), has been experimentally studied. Under the same input loadings and strain rates, changes of the light intensity have been characterized in terms of sensitivity, repeatability and linearity. Effects of the strain rate on the light intensity changes have also been investigated for both ML sensing materials. SAOED appears to perform better as an ML stress sensor than SAOE because it shows higher sensitivity and no saturation of light during the loading history. Although SAOE showed saturation of light emissions, its initial sensitivity to loading was higher than that of SAOED. Therefore, SAOE appears to be more suitable for sensors for monitoring dynamic active cracks.