Strain Or Stress Component Separation In Surface Mounted Interferometric Optical Fiber Strain Sensors

Abstract

Design flexibility is often touted as an advantage of optical fiber transducers. This advantage is exploited by formalizing the geometric design of interferometric optical fiber stress and strain sensors. The equations that govern the phase-strain correlation are used to define some basic design laws. The most common design goal is to separate strain or stress components from composite phase-strain data. This can be accomplished in a Mach-Zehnder format or in a format in which both the sensing and reference fibers are exposed to the strain field. The design laws together with simple configurations are used to devise several fiber transducers. Design flexibility exists because there are many solutions which satisfy the design objectives and constraints. The constant strain assumption is the basis of design. A comparison of the transverse sensitivity of resistance and optical fiber gages is presented.