Effects of dimensional and material parameters and cross-coupling on FBG based shear force sensor

This paper presents the results of a detailed study on the effects of various sensor parameters and cross-coupling on the performance of recently developed fiber Bragg grating (FBG) based shear force sensor. In this shear force sensor, the FBG is embedded non-rectilinearly within the layers of carbon composite material (CCM) and a layer of deformable layer material in between the CCM layers. With this embedding technique, a linear variation of the wavelength shift with applied shear force has been observed. Theoretical analysis shows the dependence of the wavelength shift on the sensor dimensions and material properties of the deformable layer. To verify the dependence of wavelength shift on various sensor parameters, a detailed parametric study has been carried out. Along with the parametric study, the effect of cross-coupling due to various perturbations, which may increase the noise level and thus increase the error in the measurement of the shear force is also studied and discussed. This includes the cross-coupling effects due to pressure, temperature and other force components acting on the sensor. Techniques to minimize cross-coupling effects are also presented.