Experimental and Theoretical Study of the Effect of Temperature on the Piezo-optical Transducer for Strain Gauges

The negative effect of temperature on the performance of different types of sensors is a common problem that needs to be addressed. It is also relevant for various types of mechanical stress sensors. Temperature changes lead to changes in sensor sensitivity, zero drift (output signal change without load change) and reduced accuracy. Recently a new type of strain gauges based on the piezo-optical effect has been proposed which differ from others by more than three orders of magnitude higher gauge factor. These gauges also exhibit temperature dependences. Experimentally using small-scale sensor prototypes the effect of temperature on both output signal and transfer ratio (and hence sensitivity) was measured. The study of the causes of these dependencies was carried out theoretically using numerical modeling. The dependence is explained by two factors: asymmetry of the controlled object geometry; simultaneous inaccurate installation of the elements of the optical circuit and a change in the peak wavelength of the LED with temperature.