Modeling and experimental strain measurements on a nonhomogeneous cylinder under transverse load

Optical fiber sensors have the capability of sensing environmental factors, including strain and temperature. In particular, optical fiber Bragg gratings have been used to create multi-parameter sensors capable of measuring axial and transverse strain in addition to temperature. These measurements are made by writing gratings into the optical fibers at two separated wavelengths, 1300 and 1550 nm, and monitoring the polarization sensitive output from the sensor. While there is an analytical model for determining the strain on a homogeneous cylinder under transverse load, these fiber optic sensors are not homogeneous as they consist of distinct regions within the fiber: core, cladding, and stress rods. We measure the strain on a multi-parameter fiber Bragg grating written at 1550nm under transverse load at 0, 15, 30, 45, 60, 75, and 90° and compare these values with an analytical solution accounting for internal stresses and transverse load.