Advanced Fiber Optic Sensing for Cryogenic Simultaneous Temperature and Strain Measurement

Accurately measuring complex temperature and strain fields is crucial in engineering, but it is particularly challenging in volatile, low-temperature environments due to the significant temperature dependence of sensor parameters. This article introduces a sophisticated model using distributed fiber optic sensing (DFOS) technique for simultaneous measurement of nonuniform fields of temperature and strain in low-temperature settings, overcoming the inherent temperature sensitivity of the sensors through Rayleigh scattering and integration with an optical frequency-domain reflectometer (OFDR). Our experimental setup involves the utilization of a single optical fiber securely affixed to the specimen’s surface in an arc-based geometrical configuration. We suggest a simultaneous and decoupling approach to rigorously segregate the harmonic components of temperature and strain fields, effectively addressing the temperature sensitivity. Extensive experiments cover uniform combined temperature and strain load scenarios, as well as scenarios involving gradient temperature-strain loads. Both arc-based and full circle-based configurations yielded consistent, robust results, demonstrating their efficiency in accurate decoupling. This highlights the DFOS’s suitability for engineering applications needing accurate, concurrent temperature and strain measurements.