A smart load-sensing system using standardized mechano-luminescence measurement

The mechano-luminescence (ML) of phosphors has stirred a great deal of interest for its potential application in inexpensive, nondestructive load sensors. However, the most serious drawback of ML phosphors has been responses that differ according to the loading conditions. This has led to a lack of standardization in realizing smart ML sensor applications. We improved the applicability of ML phosphors to that of a smart, standardized load sensor by detecting ML based on the UV excitation above the threshold power density during the entire loading process. The ML behavior under these conditions was completely different from that of conventional ML behavior with UV excitation turned off. The ML output was clearly represented as a simple linear function of the applied load under conditions that could be either static or dynamic. In addition, neither a ML loss angle nor hysteresis behavior was observed under these ML measurement conditions.