Temperature and strain sensing of critical aircraft engine components is a critical health and prognostics tool for future
engine programs. Real-time feedback of key temperature and strain measurements can be used to provide better
estimates to ground crews of engine component life, thus minimizing engine downtime and maximizing the effectiveness
of planned inspections. One method for monitoring distributed stress and temperature throughout an engine is through
the use of Fiber Bragg Grating (FBG) sensors. With just a single sensor line, both temperature and strain can be
monitored simultaneously and in a distributed fashion. Unfortunately, FBG sensors bonded to a host structure are
susceptible to both thermal strains and mechanically-loaded strains simultaneously, and without intelligent sensor design,
the two signals are indistinguishable from each other. In the present work, a sensing array design is proposed and
demonstrated to provide a means for separating thermal and mechanically-loaded strain signals by using two FBG
sensors in close proximity to each other. Experimental results are provided using a structural beam element to
demonstrate the feasibility of the proposed approach for decoupling the temperature and strain effect from fiber Bragg
grating sensors.
An innovative adaptive optic is discussed that provides a range of capabilities unavailable with either existing, or newly reported, research devices. It is believed that this device will be inexpensive and uncomplicated to construct and operate, with a large correction range that should dramatically relax the static and dynamic structural tolerances of a telescope. As the areal density of a telescope primary is reduced, the optimal optical figure and the structural stiffness are inherently compromised and this phenomenon will require a responsive, range-enhanced wavefront corrector. In addition to correcting for the aberrations in such innovative primary mirrors, sufficient throw remains to provide non-mechanical steering to dramatically improve the Field of regard. Time dependent changes such as thermal disturbances can also be accommodated. The proposed adaptive optic will overcome some of the issues facing conventional deformable mirrors, as well as current and proposed MEMS-based deformable mirrors and liquid crystal based adaptive optics. Such a device is scalable to meter diameter apertures, eliminates high actuation voltages with minimal power consumption, provides long throw optical path correction, provides polychromatic dispersion free operation, dramatically reduces the effects of adjacent actuator influence, and provides a nearly 100% useful aperture. This article will reveal top-level details of the proposed construction and include portions of a static, dynamic, and residual aberration analysis. This device will enable certain designs previously conceived by visionaries in the optical community.
Conference Committee Involvement (2)
Industrial and Commercial Applications of Smart Structures Technologies VII
10 March 2013 | San Diego, California, United States
Industrial and Commercial Applications of Smart Structures Technologies VI
12 March 2012 | San Diego, California, United States
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