Signal Processing Seminar

Accurate Calculation of the Mean Strain of Non-uniform Strain Fields Using a Conventional FBG Sensor

Aydin Rajabzadeh

In the past few decades fibre Bragg grating (FBG) sensors have gained a lot of attention in the field of distributed point strain measurement. One of the most interesting properties of these sensors is the presumed linear relationship between the strain and the peak wavelength shift of FBG reflection spectra. However, subjecting sensors to a non-uniform stress field will in general result in a strain estimation error when using this linear relationship, which is due to the difference between the average strain value over the length of the sensor and the point strain value based on the peak wavelength shift of the FBG reflected spectra. In this presentation, we will first introduce a new formulation for analysis of FBG reflected spectra under an arbitrary strain distribution. The presented method is an approximation of the classic transfer matrix model, and will be called the approximated transfer matrix model or ATMM. Using the properties of this new formulation, a new method will be presented that compensates for the mean strain estimation error, and it will be validated using simulations and experimental FBG measurements.

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Overview of Signal Processing Seminar