4 new ways the ODiSI has gotten even better!
Dawn K. Gifford, Ph.D.
Director of Product R&D, Lightwave Division
In the first half of 2012 we introduced our ODiSI B distributed fiber sensing system. With this system, simple, off-the-shelf, unaltered optical fiber can be used to measure strain or temperature at every point along the fiber. The system as introduced provides data over 10 m of fiber length with 5 mm spatial resolution and a 100 Hz update rate. This enables high resolution visibility into the strain or temperature profiles of test articles at a speed that had not previously been available.
Since its introduction, we have interacted with many customers using or interested in using the ODiSI B and we have listened to their feedback. While much of the feedback is positive, we always ask “what will make this system even more useful for you?” Answers include the typical “better, faster, and cheaper.” While we had already addressed “better, faster and cheaper” in a significant way with the ODiSI B introduction (easier to use and over 10x faster and 2x less expensive than its predecessor), we listened to our customers’ requests. In response, we have now released new software with better performance (available free to all current ODiSI B owners) and new options (available for purchase) for the ODiSI B that include “faster,” “longer,” and “more resolution.” The table below outlines the new options available on the ODiSI B platform. These are modes of operation that a user can select using software controls. As such, they make the system a more flexible tool for a variety of applications. In addition to these measurement modes, we’ve also added an option for users to key their own sensors, making it possible for users to make custom sensors from their own spools of fiber.
With the high speed option, a user can capture data at 250 Hz over a two meter sensor length. This makes it possible to measure more dynamic events such as the 30 Hz oscillation shown below. This feature is useful in a variety of applications including testing automotive components, dynamic testing of aerospace parts, or for measuring a rapid thermal response.
Some of our customers wanted to look at larger areas or larger test structures and requested the capability to measure with longer sensors. The new extended length option enables measurements of fiber sensors up to 20 m long. (Note that the system comes with a 50 m standoff cable so the system can be remote from the test article; sensor lengths are measured after this standoff.) With this longer length sensor, users can instrument a longer span of an aircraft wing or wind longer lengths of fiber into a composite pressure vessel for integrated health monitoring and non-destructive testing.
The high resolution mode of operation provides a sensing point every 1.25 mm on fiber sensors up to 10 m long. With this option, users can see more details in a strain or temperature profile. For example, this level of resolution was necessary to fully capture the locally high strains in the data below. High spatial resolution is useful for finding and quantifying local defects or measuring an article where high strain gradients are expected (when fiber is embedded in a composite material, for example).
Key your own sensors
Sensors purchased from Luna are characterized and shipped with a file known as a “key” that is used for sensor identification and as a reference scan for measurements. As such, they are “plug and play” and ready for immediate use. All sensors must have an installed key for use with the ODiSI B system. In some cases, users may want to make custom sensors from a spool of fiber or to bond or embed a fiber without a connector and splice on a connector afterwards. In these cases, we now provide a hardware/software option to measure the sensor and create a “key” file. We can also provide equipment and training for splicing, connectorization, and proper termination.
A better, more flexible system
We are excited about the new options available on the ODiSI B platform and hope this makes the system more useful for our customers in their many and varied applications. As usual, we are always listening with open ears for feedback on our products. What would you like your Luna system to do?