Optical fiber sensors for spacecraft applications

Abstract

Optical fiber sensors offer a number of advantages for spacecraft applications. A principal application is strain sensing for structural health monitoring, shape determination, and spacecraft qualification testing. This paper will review the results of recent work at the Naval Research Laboratory where optical fiber strain sensors have been used on spacecraft structures and ground test hardware. The sensors have been both surface mounted to the structure and embedded in fiber-reinforced polymer composites. The issue of potential strength reduction of high-performance composites due to embedded optical fiber sensors and leads has been studied, low-cost fabrication of tubular struts with embedded sensors has been demonstrated, and a novel technique for fiber ingress-egress from composite parts has been developed. Applications of fiber sensors discussed in this paper include distributed dynamic strain monitoring of a honeycomb composite plate and a lightweight reflector during acoustic qualification tests, ultrahigh-sensitivity static strain and temperature measurements for precision structures, and on-line system identification of a lightweight laboratory truss.

Characterization and analysis of carbon fibre-reinforced polymer composite laminates with embedded circular vasculature

“…Such findings agree with the compressive strength reductions reported in the FOS studies, which found a range of values from 30 to 70 per cent, depending on FOS orientation, laminate thickness, host composite, etc. ( Jensen et al 1992b;Friebele et al 1999;Shivakumar & Emmanwori 2004;Kousourakis et al 2008). Note that the last column in table 4 indicates the proportion of laminate specimens failed in 'predicted failure mode' (i.e.…”

“…Jensen and colleagues (1992a,b) are among the pioneers to study the influence upon host composite performance following embedment of FOS with regard to orientation and numbers of FOS. Subsequent researchers concluded that the degradation of material strength and modulus is significantly affected by the optical fibre diameter, the FOS orientation relative to nearest plies and the FOS materials (Friebele et al 1999;Zhou et al 2004;Fernando & Degamber 2006). Apart from modifying the diameter and constituent materials of FOS in order to reduce their influence on resulting performance, it is the resin-rich pocket caused by off-axis FOS embedment that draws the attention of most researchers.…”

Mechanical Property and Strain Transferring Mechanism in Optical Fiber Sensors

“…However, such a protection results in inconsistency between the fiber strain and the structural strain. Such discrepancies are neglected in many applications of OFSs by simply assuming that the fiber strain is consistent with the host structural strain (Friebele et al, 1999;Udd, 1995). Such assumption gives acceptable measurement results for the OFSs with long gauge length, in which the peak host strain can be fully transferred into the fiber strain, but cannot provide good measurement strains for short gauge OFSs, for instance, FBG sensors, in which the effect of the bonded fiber length on strain transfer between the fiber and host structure is significant (Galiotis et al, 1984).…”

Real-Time Train Wheel Condition Monitoring by Fiber Bragg Grating Sensors

“…Typical wavelength changes of FBG written in standard single-mode fiber at 1550 nm region due to mechanical strain and temperature variation are ∼1 pm/με and ∼11 pm/ • C, respectively. Because of its compact size, low optical loss, self-referencing, and wavelength multiplexing capability, FBG sensors have been widely applied in a wide range of condition monitoring applications [9,[15][16][17][18][19]]. …”