Since the early days of flight gyroscopes have acted as a key enabling technology for stabilization and guidance of aircraft and rockets. Mechanical gyros were the first to be used. They suffered from repeated failures and were aggressively replaced by ring laser gyros beginning in the late 1970s. Almost in parallel with the introduction of ring laser gyros, the first solid state gyros based on fiber optics began their development, at about the same time I began working on fiber sensors at McDonnell Douglas. This paper summarizes thoughts on the past, present and future of fiber optic gyros.
In order to characterize energetic materials, it is highly desirable to be able to measure velocity, position, pressure, and temperature throughout the event. This paper looks at approaches associated with extracting these parameters from data obtained using high speed fiber grating sensor systems. Prior work has demonstrated that velocity, position, and local pressure data may be obtained using chirped fiber grating sensors (CFBGs). Uniform fiber grating sensors have been used to quantify local pressures beyond the range associated with CFBGs. A main challenge faced today is the separate of these parameters from temperature. A novel approach that may be used to isolate temperature and pressure measurements using a high-speed fiber grating sensor system is presented in this paper.
Over the last 40 years the fiber optic sensor field has changed dramatically. This was driven in part by advances in optical components, optoelectronics, and semiconductors coupled with the emergence of fiber optic communication, compact disks, and DVD readers. This paper contains some illustrations on how key fiber optic sensors have evolved and are interrelated. These improved fiber sensor designs over time in combination with improvements in system components have allowed performance and cost improvements that have resulted in penetration into aerospace and defense, civil structures, oil and gas, electric power, and medical applications.
A very high-speed fiber Bragg grating sensing system has been used to characterize energetic materials in card gap and Russian DDT tests1,2. This paper reviews the system capability of measuring the position, velocity, pressure, and temperature associated with energetic events. A readout system based on optical beam conditioning and high-speed detectors sends data from fiber Bragg grating sensors under extreme environments to a digital oscilloscope where events that occur on the order of a few nanoseconds can be resolved.
Fiber gratings have been used to measure strain fields in pressure vessels made of composite materials and aircraft adhesive joints1 . Measuring transverse loads have traditionally been performed by inducing a differential strain across the optical core of a fiber. Small changes in load cause the birefringence in the fiber to increase and capturing the spectral shifts using this method necessitates extremely accurate readout systems and careful analysis. This paper suggests a new approach for measuring transverse load by converting it to longitudinal strain and covers a very high-speed system used for measuring velocity, position, and pressure events that are on the order of a few microseconds.
In 1977 McDonnell Douglas Astronautics Company began a project to investigate the usage of optical gyros to support
the Delta Launch vehicle. This resulted in the invention of the closed loop fiber optic gyro and several derivative
inventions that allowed entry into acoustics for undersea applications, launched the field of fiber optic smart structures,
and resulted in some strange detours into secure fiber optic communication. Health monitoring activities with Blue
Road Research, Inc. and later Columbia Gorge Research, LLC continuing to develop fiber sensors for an ever wider
range of use including civil structures, oil and gas, environmental sensing, high speed machining, composite
manufacturing, energetic materials, robotic surgery and electric power. This paper primarily follow the path to the
moon, Mars and beyond with the objective of showing how fiber sensors are helping us to get there and ultimately will
help us stay there.
Fiber Bragg grating (FBG) and other fiber optic based sensors have been used to sense environmental parameters for numerous applications including aerospace, oil and gas, civil structure health monitoring, mining, and medical. There are many benefits to using fiber optic based sensors over traditional electrical sensing methods. These advantages include: immunity to electromagnetic interference, high bandwidth, low loss, small, lightweight, and portability. New developments allow these physical measurements such as strain, temperature, pressure, vibration, and acoustics to be made at extremely fast speeds extending the capability of fiber optic sensor systems to monitor impacts and other rapid events.
In 1977 McDonnell Douglas Astronautics Company began a project on using fiber optic sensors to support the Delta
Rocket program. This resulted in a series of fiber sensors to support the measurement of rotation, acoustics, vibration,
strain, and temperature for a variety of applications and early work on fiber optic smart structures. The work on fiber
optic smart structures transitioned in part to Blue Road Research in 1993 and continued in 2006 to the present at
Columbia Gorge Research. This paper summarizes some of the efforts made by these companies to implement fiber
optic smart structures over this forty year period.
In 2006 an approach was developed that used chirped fiber gratings in combination with a high speed read out configuration to measure the velocity and position of shock waves after detonation of energetic materials. The first demonstrations were conducted in 2007. Extensions of this technology were made to measure pressure and temperature as well as velocity and position during burn, deflagration and detonation. This paper reviews a series of improvements that have been made by Columbia Gorge Research, LLC, Lawrence Livermore National Lab and Los Alamos National Lab in developing and improving this technology.
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