Resonant Piezoelectroluminescent Fiber-Optical Sensor of a Temperature Field in Composite Structures

摘要： A dynamic mathematical model of functionation of a fiber-optical sensor in the process of resonant diagnosing of a temperature field inhomogeneous along the longitudinal axis of the sensor is developed. The resonant approach is based on a given amplitude-frequency characteristic of forced stationary electroelastic vibrations of a local section of the sensor caused by the action of the harmonic component of controlling voltage (CCV) on its electrodes; the constant CCV is necessary for tuning the sensor to the operating mode in the range of temperatures considered. The density distribution function of temperature along the sensor is found by solving the Fredholm integral equation of the first kind using the measured values of derivative with respect to the frequency of the harmonic CCV of the function of the amplitude of intensity of glow at the exit of the fiber-optical sensor. A method for resonant scanning of an ina uniform temperature field along the longitudinal axis of the sensor is developed; the method uses a new algorithm for processing the intensity of informative light signals at the exit from the optical fiber for various frequencies of the harmonic CCV. Results of a numerical modeling of the function of intensity of light pulses at the exit from the fiber-optical sensor, of the distribution of voltage amplitudes on the electroluminescent layer and of resonance frequencies along the sensor axis are presented for diagnosing an inhomogeneous model temperature field.