<title>Structural testing of a Navy LPD-17 propulsion propeller using Bragg grating sensors and digital spatial wavelength domain multiplexing (DSWDM)</title>

Abstract

Systems Planning and Analysis, Inc., under sponsorship from the Office of Naval Research (ONR), has developed a proprietary structural health monitoring system for large- scale structures based on optical fiber Bragg grating (FBG) sensors. This paper describes the operational capabilities of the health monitoring system and recent rest results on large-scale naval structures performed at Naval Surface Warfare Center, Carderock Division (NSWCCD). DSWDM technology developed under this effort is electro-optics based and has been shown to provide significantly higher sampling rates than comparative FBG interrogation technologies. The baseline system under development interrogates more than 120 sensors along five fiber channels. The prototype DSWDM system also possesses a number of advantages intrinsic to optical fiber sensors as compared to resistance strain gages (RSGs). These advantages include extremely low installed weight and volume, immunity to electromagnetic interference and corrosive environments, and low signal attenuation and drift. The LPD-17 propeller was retrofitted with 24 FBGs and strain and temperature data was recorded for direct comparison with conventional RSGs. Static and dynamic full- scale propeller operating loads were applied to the LPD-17 propeller. Sampling rates of approximately 1.7 kHz were demonstrated using the DSWDM system that provided good agreement in measured strain levels between FBGs and reference RSGs.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.