To date I have blogged about the use of fiber optic sensors in the geotechnical (DUSEL) and wind energy (Sandia National Labs) sectors for structural health monitoring. We have now released a case study showing how FOS is being utilized in the nuclear power industry to monitor post tensioned tendons in a nuclear containment structure on an operational nuclear power plant. This pilot project is still currently active and the system is still collecting data.

- Alan Turner

For years, Micron Optics has touted the benefits of fiber optic sensors – specifically fiber Bragg grating (FBG) based strain and temperature sensors. We have worked to make clear that we do not see FBG sensors as an across-the-board replacement for conventional foil strain gages or thermocouples. They’re not. FBG sensors make sense where there is a special challenge that is addressed by one of many inherent advantages of fiber optic sensors.

National Instruments has done a good job of highlighting some examples of this in a recent “NI Developer Zone” blog post. It focuses on FBG’s immunity to EMI, intrinsically safe operation, multiplexing capability and small size and how these attributes address needs in important fields of application. See the complete post here:

http://zone.ni.com/devzone/cda/pub/p/id/1523metc=mt4psm

National Instruments recognizes how fiber optic sensors enhance their capability to address a much broader field of sensor applications. Kellis Garret, Product Marketing Engineer for NI’s fiber optic sensing instruments, says “Many of our customers are just learning about the power of FOS and are now making measurements that simply were not possible with conventional gages.” Look for more FOS information at ni.com, including NI-OSI (NI’s FOS interface), LabVIEW drivers for Micron Optics interrogators, and training tools to bring yourself and your team current on FOS technologies.

- Tom Graver

For the 4th consecutive year, Micron Optics Inc.  has been invited to participate in the 2012 Wind Turbine Blade Workshop, sponsored by Sandia National Laboratory.  In 2008, Micron Optics and Sandia began collaborating to study the value, reliability and effectiveness of commercial Structural Health Monitoring (SHM) technologies for use on operational wind turbine blades. The goals, as well as sensor types and analyses methods to be utilized on the  Sblade Project, were presented in the 2009 workshop in a co-presentation between Mark Rumsey of Sandia National Laboratory, Jason Kiddy of Aither Engineering and Alan Turner of Micron Optics Inc.  http://windpower.sandia.gov/2009Reliability/PDFs/Day2-08-MarkRumsey.pdf .

The focus at that time was to investigate the survivability of the various sensor types during the life cycle of a wind turbine blade – from sensor installation during blade manufacturing, to turbine construction during operation (i.e., power generation from fall 2009 to spring 2010), and finally through accelerated fatigue life cycle testing.

At the 2010 workshop, I summarized the performance of the fiber optic sensing system: http://windpower.sandia.gov/2010BladeWorkshop/PDFs/1-E-2-Turner.pdf. The Sblade program demonstrated that fiber optic sensing (FOS) is a viable and reliable sensing technology for the next generation of wind turbines.   FOS out performed all other sensing technologies on SBlade to the extent that FOS became the primary technology used in the follow on phases.

The follow up programs 2010 to present, the Smart Blade and Smart Rotor programs, have used FOS for a total of 6 blades. In the 2011 workshop, Jon White shared his vision for how smart rotor technologies will improve  efficiencies of individual turbines and the plant as a whole http://energy.sandia.gov/wp/wp-content/gallery/uploads/2-D-4-White-SAND2011-5557C.pdf

Going forward, FOS will play an integral part in wind turbine efficiency.

- Alan Turner

In May of 2011, I blogged about a fiber-optic-based rock deformation measurement system at the Sanford Underground Research Facility (SURF) (formerly the Sanford Underground Science and Engineering Laboratory (SUSEL)). www.sanfordundergroundlaboratoryathomestake.org .

SURF is an interim facility under construction while DUSEL funding is pending from the DOE. Last week, Fermilab www.fnal.gov hosted a DuRa meeting attended by physicists and scientists from all over the world. This meeting was held to update the community on the progress of the current and future experiments at SURF.

During the meeting members of DuRa viewed a live feed of an experiment at the 4100ft level of the Homestake Mine in Lead, SD. This experiment involved loading the rock mass with a 100 ton capacity jack. More than 30 FBG based strain gages recorded the rock deformation during loading.

Both “strain strips” (a clever embedded strain measurement transducer created by the GEOXTM Team) and Micron Optics os3600 long gage strain sensors, embedded and mounted on the surface, successfully measured changes in the rock as small as a few microns.

This system has been live 24\7 for nearly three years. Stay tuned as I will post the new data as it becomes available.

To view the pre-recorded “live” feed follow this link : http://vmsstreamer1.fnal.gov/VMS_Site_02/Lectures/DURA/120119Roggenthen/index.htm
Note this link best viewed with Firefox or Safari as some viewers had issues with viewing in IE.

You can also view some quick data plots from the experiment.

Alan Turner