Earlier this year, the White House agreed to spend up to $2 trillion to help fix our nation’s aging infrastructure. While the largest chunk will likely go to roads, bridges, and transit, there is also talk of improvements for wastewater, harbors, and airports, as well as a more efficient energy grid to transmit energy over longer distances. This much-needed, enormous undertaking will not only involve demolishing and rebuilding existing infrastructures, but also assessing structural integrity and repairing structures that may not require drastic measures such as demolition or replacement.
With that in mind, engineering firms, construction companies and manufacturers will likely see a surge in nondestructive testing (NDT) or nondestructive damage evaluation (NDE) over the next few years. NDE consists of a variety of non-invasive inspection techniques used to evaluate material properties, components, or entire structures and assemblies. The techniques can also be utilized to detect, characterize, or measure the presence of damage (e.g. corrosion or cracks). The purpose of NDE is to inspect a component or structure in a safe, reliable, and cost-effective manner – without causing further damage. This contrasts destructive testing, where the part being tested is damaged or destroyed during the inspection process. NDE can be performed during or after manufacture/construction, or even on edifices or structures that are currently in use. NDT inspections can be used to assess the current state of a structure, monitor its ongoing health, and make informed evaluations on its remaining lifespan.
While there are many methods to conduct NDT, such as eddy current, radiography, magnetic particles, etc., a practical alternative to these methods which is generating excitement within the civil, nuclear, and oil and gas industries is distributed strain and temperature sensing using optical fiber-based sensors. There are several factors driving interest in distributed sensing. First, old methods fail to provide the spatial coverage required to locate every conceivable potential damage area, as well as the global response to the presence of localized damage. In other words, the exact location of the fault and the effect it has on the rest of the structure. Distributed sensing provides ultra-fine spatial resolution across tens of meters of sensor length, providing spatially continuous information over large areas. Another reason is the technology’s ability to assess a wide variety of structures and subsystems. Distributed sensing is just as useful detecting cracks on a large building as it is quantifying damage to the interior of a pipe or determining loads on and within concrete and concrete-embedded rebar. Distributed sensors are also able to be installed on, around, and in complex geometries and difficult-to-reach spaces. Finally, with traditional coarse sensor layouts, large-scale structures typically experience a significant amount of damage prior to revealing the existence and location of that damage. With distributed sensing, near continuous information detects failure modes far in advance of any damage.
How is this accomplished? Sensuron’s sensing systems monitor strain and temperature distributions by transforming an optical fiber into a spatially continuous sensor that performs like thousands of strain gauges or thermocouples installed adjacent to one another. The sensors are easier and require far less time to install, and last orders of magnitude longer than traditional technologies. This allows engineers to detect early stages of material degradation related to fatigue, overloading, aging, thermal cycling, and corrosion rapidly, reliably, and without jeopardizing the health or safety of the structure they’re charged with evaluating. This is good news for a nation about to undergo an infrastructure overhaul.
For More Information:
View a NDE demonstration video