Measurement of strain with strain gauges and FBG strain sensors

The relationship between stress put on a material and the resulting deformation is defined by Hooke’s Law that has been around since 1678. Different techniques and technologies have been used to measure the law over different periods of time. In the past mechanical strain gauges have been used to measure strain applied to a material. The first strain gauges were analog. Some of these devices, like springs and levers, are still used today, but they are not accurate enough as the strain applied to the material would have to be quite high for the device to register it. Strain gauges have a number of disadvantages, one of them being the need to be clamped firmly so the device didn’t move which causes an inaccurate reading.

The next step in strain measurement techniques were resistive strain gauges, the most common of which are foil resistive gauges. These devices are better than the previous model as they are sensitive, accurate, easier to produce. However, the lack of foil elasticity poses limitations on the device, for example, resistive strain gauges cannot be used for ductile materials. To overcome this downside conductive material can be added to elastomers for a stretchier gauge.

The best solution that has been developed so far for strain measurements are fiber Bragg grating strain sensors. They are still catching on as their initial price and lack of awareness slowed their adoption among industry professionals. However, the price of FBG strain sensors is dropping every year which is tied with the level of development of fiber optic technology.

The low price of FBG sensors makes them available for different applications, some of which include automotive, medical, aerospace, and energy markets. FBG strain sensors have been found to be useful in aerospace applications where they are used to determine wing loading while providing accurate fuel readings. Civil engineers utilize FBG sensors for structural health monitoring. The operational life of vehicles can be determined with the use of FBG sensors that are widely utilized by automotive designers. FBG strain sensors are lighter, easier to install, and less expensive than strain gauges.

Optromix, Inc. is a U.S. manufacturer of innovative fiber optic products for the global market, based in Cambridge, MA. Our team always strives to provide the most technologically advanced fiber optic solutions for our clients.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line: fiber Bragg grating sensors, FBG interrogators, and multiplexers, Distributed Temperature Sensing (DTS) systems. We create and supply a broad variety of top-notch fiber optic solutions for the monitoring of various facilities all over the world.

If you are interested in Optromix FBG strain sensors, please contact us at info@optromix.com

Fiber Bragg grating sensor systems in structural health monitoring

FBG sensors for structural health monitoringA traditional way of monitoring structural health is through the use of piezoelectric transducers; these devices convert pressure to an electric voltage. Transducers are reliable and accurate in most working conditions except in cases of corrosive environments or under high temperatures, above 300° Celsius. Harsh conditions influence reliability.  accuracy, and usefulness of transducers in a negative way.

A new solution for structural health monitoring has been developed to accommodate the needs of the industry. Fiber-optic based technology, like fiber Bragg grating sensors, are more reliable under harsh conditions such as high temperatures and corrosive environments; they are immune to electromagnetic interference that is detrimental to piezoelectric transducers’ operation. FBG sensors are designed to operate under harsh conditions and provide reliable data. Fiber Bragg grating sensors are able to measure a variety of factors, such as temperature, strain, pressure, the appearance of cracks, etc.

The reliability of FBG sensors for structural health monitoring is ensured by the simplicity of the optical fiber material—fused silica—that forms the fiber. FBG strain sensors and FBG pressure sensors are especially useful in monitoring the condition of critical infrastructures operating under harsh environments, such as modern superheaters or nuclear power plants, thus ensuring the continuous operation of power plants, preventing catastrophic consequences of structural failures.

One of the applications of FBG sensors is the monitoring of the P91 pipes widely used in the industry. These pipes transmit high-pressure steam, which is both high-temperature and corrosive. Fiber Bragg grating temperature sensors indicate overheated pipes that may be under too much stress. FBG pressure sensors are used to detect critical increases in pressure within pipes to prevent premature breakdown of the systems.

One of the advantages of fiber Bragg grating sensing systems is its cost-effectiveness. FBG sensors’ price is low compared to other methods of temperature, strain, and pressure measurements.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line: fiber Bragg grating sensors, FBG interrogators, and multiplexers, Distributed Temperature Sensing (DTS) systems. We create and supply a broad variety of top-notch fiber optic solutions for the monitoring of various facilities all over the world.

If you are interested in Optromix FBG sensors, please contact us at info@optromix.com

Crack monitoring of wind turbine foundations using FBG strain sensors

FBG strain sensors for crack monitoringThe increased demand for energy due to the growing population has forced the industry to develop new sustainable ways to produce energy. Among new and developing energy technologies are wind turbines. They are widely used to produce energy in many parts of the world. However, there are multiple concerns that are yet to be solved, one of them has been the lack of effective monitoring devices and techniques. Structural health monitoring of wind turbines is needed to ensure that the infrastructure around wind power remains reliable. It is crucial to monitor the operation of wind turbines to ensure effective wind power generation and avoid costly downtimes.

Besides monitoring of wind turbine temperatures, which can be effectively performed with the use of FBG temperature sensors, the monitoring of wind turbine foundations can prevent premature decay of the foundations and prolong the operational time of the turbines. Often the access to the underground part of the foundations is limited, therefore the degradation of onshore, reinforced-concrete wind turbine foundations is assessed via above-ground inspections, or through excavations that suspend energy generation. Sustained measurements of crack behavior could be used to quantify the risk of water ingress and reinforcement corrosion. However, the cracks that occur during turbine operation are not monitored. A solution to this issue is the use of fiber Bragg grating sensors.

Subterranean fiber Bragg grating strain sensors can be used to monitor the opening and lateral displacements of foundation cracks during wind turbine operation. Cracks that occur in the foundation of the turbines are often caused by the vibrations that are produced by turbines themselves. Therefore crack displacement results that are obtained via FBG strain sensors installed on the foundations are correlated with the strains measured by the second series of FBG sensors affixed to the turbine tower and verified against wind speed and turbine data from the operator.

The use of FBG strain sensors can be used to better assess the risks of water ingress and subsequent corrosion of the foundation’s steel reinforcement. The data obtained by fiber Bragg grating sensors may help engineers to more accurately determine the current asset lifetime and the design and construction of foundations in the future.

Fiber Bragg grating strain sensors demonstrate lots of advantages compared to the regular electrical strain gauges. Namely, they are immune to electromagnetic interference and power shortages. Compact size devices provide the most accurate measurements. FBGs are, literally, the best strain sensors right now.

If you would like to purchase Optromix FBG Strain Sensors, please contact us: info@optromix.com or +1 617 558 9858

Fiber Bragg grating sensors for harsh environments

FBG sensors for harsh environmentsThe demand for data is growing exponentially, piling pressure on networks to deliver more data, faster, over longer distances. Fiber optic systems have greatly improved data transfer and the gathering of information. However, complex applications require fiber optic systems to perform flawlessly, therefore, the choice of the right sensors is crucial.

The design of innovative fiber Bragg grating sensor systems has been pushed by the new societal and technological trends, such as increased mobility. Customers are looking for more data that is delivered faster both indoors and outdoors. Fiber optic sensing systems provide an easy way to install fast and reliable data links that are able to carry large amounts of data. The use of FBG sensors is expanding rapidly as they are adapted to harsh and extreme environments. It is important, however, that customers determine specific technical requirements and evaluate the possible conditions of use. FBG sensors systems provide multiple advantages that determine their wide application use. First of all, FBG sensors are able to withstand extremely high and low temperatures in a range of -40°C to +85°C. FBG sensor systems are immune to corrosion, are resistant to salt mist, vibration, and shock. The sensors are easy to handle and mount on any surface, and their coating protects them from any outside influence and significantly reduces maintenance.      

One of the areas of application of FBG sensing systems is the oil and gas industry. FBG sensors are used to decrease costly downtimes and accidents during the extraction of natural resources in hazardous offshore and onshore environments. The dependable operation of FBG sensors allows for efficient extraction. Fiber Bragg grating sensors have also improved the performance of seismic evaluation devices, monitoring, and infrastructure maintenance.

Optromix, Inc. is a U.S. manufacturer of innovative fiber optic products for the global market, based in Cambridge, MA. Our team always strives to provide the most technologically advanced fiber optic solutions for our clients.

We are dedicated to delivering the best products and supports to all our customers, our engineers have extensive experience and strong technical expertise in creating fiber Bragg grating products.

If you would like to purchase FBG sensors, please contact us: info@optromix.com or +1 617 558 9858