Sense the difference
slipping layers = distorted readouts
(cannot give accurate measurements)
no layers = reliable readouts
(can give accurate measurements)
low measurement range ±1%
(cannot measure large local strains caused by cracks and fractures)
high measurement range ±4%
(can measure large local strains caused by cracks and fractures)
unable to detect some phenomena
(cannot be used as a reference tool in scientific surveys)
sharp and accurate view of any phenomena
(can be used as a reference tool in scientific surveys)
fragile & easy to yield
(cannot be used as a substitute for steel reinforcement)
durable & heavy duty
(can be used as a reinforcement for concrete or ground)
designed to remember events
(cannot monitor actual state of the structure)
designed for structural health monitoring
(can assess the actual state of the structure)
Sensing cables versus DFOS strain sensors:
The terms „sensing cables” and „fibre optic sensors” are often used interchangeably. However, there are fundamental differences between these two solutions. As opposed to layered sensing cables, monolithic strain sensors offer considerably improved measurement quality, encompassing all of the positive attributes of the sensing cables and more, while having none of their drawbacks.
NERVE composite DFOS sensors are characterized by:
- monolithic cross section without any intermediate layers, guaranteeing no slippage and debonding effects and therefore providing accurate strain transfer. There is no need for applying advanced mathematical models during crack analysis;
- composite core without plastic or steel elements. This provides a much wider elastic range of even ±4%, taking full advantage of the optical fibre’s operational range. There is no risk of the sensor being damaged, even within the area of localized cracks. Importantly, the sensor reflects the actual, not historical, state of the structure;
- rough/ribbed external surface allows for perfect bonding with the concrete or ground. As the sensor itself becomes an integral part of the structure, it provides great interoperability and accurate strain transfer.