Fatigue Performance Comparison between OFDR-based Distributed Fiber Optic Sensing and Strain Gages
Compares strain measurement in high strain range, cyclic loading between fiber and foil gage, showing foil gage drifting from the start
Resistive strain gage cycle life decreases dramatically as strains reach values of 2000-4000 μstrain1. This results in early gage failure and the inability to accurately assess structural performance from load and deflection controlled tests. The superior characteristics of fiber optic strain sensors pave the way for overcoming this limitation and support their use for fatigue testing and other high-strain cyclic monitoring. Luna’s Optical Frequency Domain Reflectometry (OFDR)-based distributed fiber optic sensing technique provides the ability to make numerous strain measurements with millimeter spatial resolution along the length of an optical fiber. OFDR is the underlying technique used in our OBR, ODiSI, and DSS product lines for distributed sensing. This Engineering Note presents comparative measurements between foil gages and fiber optic sensors in two experimental configurations.