APPLICATION HANDBOOK - Technobis

Technobis supports her customers in

transforming basic ideas to scalable products

& applications.

Technobis tft-fos is the global leader in Application Specific Photonic Integrated Circuit (ASPIC)-based Fiber Optic Sensing systems for high performance market segments such as high-tech systems, aeronautics, space, medical and automotive testing industries.

The application of the superior technology of integrated photonics has proved to be capable of supporting both new and existing sensing and monitoring solutions for a broad range of applications.

Our fiber optic sensing solutions can be used for structural health monitoring of composite materials, predictive maintenance in the energy market, shape reconstruction for planes & buildings, flow, temperature & pressure sensing integrated into medical devices.

Our spectrometer Our interferometer Our switch Our lightsource

CONTENTS

Introduction 3

Landing Gear Load Sensing 4

Helicopter Blade Monitoring 5

Shape Sensing on Morphing Wings 6

Damage Detection in Composite Aerospace Structures 7

Impact Detection 8

Integrating Sensing and Data Communication 9

MyriadGator for affordable and high performing distributed FBG sensing 10

Force Transducer for cardiac interventions 11

Haptic Feedback with Fiber Optic Sensing 12

RF/MRI compatible in-vivo temperature sensing 13

Multi-point blood pressure sensing 14

Shape Sensing for minimal invasive instruments 15

Shape Sensing with a multicore optical fiber 16

High Resolution Strain Measurements 17

High Resolution Temperature Measurements 18

High dynamic strain range and -resolution with Fiber laser sensor 19

Multi-parameter sensing 20

Wind Turbine Monitoring 21

Wind Turbine Blade Monitoring 22

Crash Testing 23

Downforce and Vibration Measurements in Race Cars 24

Luxury yacht monitoring 25

Underwater Shape Sensing 26

Shape Reconstruction for Structural Deformation 27

Hans Roeland - Poolman

Business DeveloperGator systems

[email protected]

Pim Kat

CEO Technobis Integrated Photonics Technology

[email protected]

Ellen Schipper

Sales Gator systems

[email protected]

Elvis Wan

Process Development Engineer ASPIC Packaging

[email protected]

INTRODUCTION

“Smart Sensing Solutions for the Technical Challenges of Tomorrow.”

3

LANDING GEAR LOAD SENSING

In the CleanSky 2 program Technobis is partner in the ALGeSMo project to

develop a sensing system that will measure load at the landing gear. The

objective for this system is to provide load data for use in aircraft systems that

can be integrated with aircraft Health Monitoring, hard landing detection,

flight management and flight controls.

The project is taking a fully integrated system from post-TRL 4 through to flight test on a single-aisle aircraft and to the demonstration of a working aircraft-integrated system at TRL 6. This includes the integration of load and torque sensors into large passenger aircraft landing gear to provide robust, accurate, reliable load measurements and the potential for Health Monitoring capability. The sensors will measure loads using Fibre Bragg Grating technology integrated into Airbus-patented landing gear.

The project covers a complete framework of activities, starting with the integration of dedicated optical fibers into composite structures, the readout of the optical fibre sensor with state-of-the-art miniature and reliable ASPIC-based FBG Interrogator Technology from Technobis.

For this purpose Technobis developed an OEM multi-channel and high speed FBG interrogator device, called LandingGator. Although the system is developed in the context of the landing gear load sensing application, the system being qualified for the aerospace environment actually supports many more aerospace sensing applications where multiple fiber optic channels and high speed FBG interrogation is required, such as damage and impact detection, shape monitoring of morphing structures and structural load sensing.

HELICOPTER BLADE MONITORING

The advancement of Fiber Optic Sensing Networks for load and vibration

monitoring presents important possibilities for helicopter rotor health and

usage monitoring. While main rotor blades account for the main source of lift

for helicopters, rotor induced vibration establishes an important source for

understanding the rotor performance and blade condition.

Since December 2017 Technobis FBG Interrogator systems are being Flight Tested on a helicopter with an Integrated Photonics based Multi-Channel Miniature fiber sensing device called HeliGator, directly mounted on the root of the helicopter blade. Measurement data was recorded and wirelessly transmitted to a central processing CPU located in the avionics area.

The objective of these Flight tests is to demonstrate that the main rotor loads (bending moments, torsion and axial strain) recorded by the FBG sensor data system to be correlated by an existing strain gage data system. With this effort the system will achieve high TRL, constituting full functional prototype demonstrated airworthiness in a real operational flight environment.

Thijs van Leest

[email protected]

Rolf Evenblij

Program Manager [email protected]

4 5

SHAPE SENSING ON MORPHING WINGS

Conformal morphing technology is a new area to the aircraft industry. The ability of an aircraft to change the shape of its wings during flight allows it to perform a flight mission more efficiently than a fixed-wing aircraft (due to drag reduction and improved lift-to-drag ratios) and thus attracts much interest from both the military/government and the private aircraft industries. Shape sensing is one of the versatile applications in a wide market spread, made practical with Fiber Optic sensors for strain sensing. In the SARISTU project, a fiber optic based sensing approach for chord-wise shape reconstruction of an adaptive trailing edge device (ATED) is realized with the extrinsic implementation of fiber FBG sensors. With this implementation, the capability is provided for a closed-loop control of the morphing mechanism for a given set of the target shapes.

Rolf Evenblij


DAMAGE DETECTION IN COMPOSITE AEROSPACE STRUCTURES

Damage detection is a major challenge in the aviation industry, in particular with regard to the use of composites materials in aircraft structures. As composites materials prove to be cost effective for structures they also exhibit damage effects that require new perspectives for detection. Delamination effects and debonding of stringer runouts are examples that are barely visible and need NDT techniques in AOG situations for assessment of the damage. Although several approaches exists and are being developed, the damage detection algorithms currently applied in combination with integrated photonics based sensing equipment from Technobis are based on a modal (vibration) approach with the ability to detect the presence and location of the damage in a composites structure with a relatively limited number of sensor positions. Different methodologies can be applied to measure the dynamic response of structures for assessment of damages, i.e. Modal Strain Energy Analysis, Acousto-Ultrasonic sensing (Acoustic Emission, and Lamb waves). The methodologies involve sample rates ranging from 1 kHz to 1Mhz. Technobis is developing the SuperGator in the EU-project EXTREME that supports such wide range of sample rates maintaining the specification of sub micro-strain resolution for large dynamic strain ranges.

Rolf Evenblij


6 7

IMPACT DETECTION

Impact detection in aeronautical structures allows predicting their future reliability and performance. An impact can produce microscopic fissures that could evolve into fractures or even the total collapse of the structure. FBG sensor networks applied for damage detection can also be applied as impact detection system during flight and even on the ground to determine the location of any significant impacts. Subsequently, based on the results from the less accurate impact detection system (using the same sensor network); a damage detection can be performed on the part of the structure where the impact was located.

In the Dutch national program TAPAS (Thermoplastic Affordable Primary Aircraft Structures) Technobis successfully performed impact tests on a thermoplastic composite aircraft wing structure, e.g. an overburdened torsion box representative for the load carrying box of an airliner flap of the tail of a business jet. The objective of the test was to obtain more information about impact detection on composite structures by measuring the time of arrival of the signals to the various sensors (Time Difference of Arrival, TDOA).

Rolf Evenblij


INTEGRATING SENSING AND DATA COMMUNICATION

In practice redundancy issues and smart sensing are addressed in solution developments allowing bi-directional interrogation combined with smart sensor networking and integrated data communication. Technobis successfully demonstrated continuous bi-directional FBG interrogation while maintaining high bandwidth data communication speeds. Such a concept allows a first degree sub-system failure, keeping remaining systems fully functional. Smart network management for instance allows immediate rerouting of both measurement and control data through distributed network nodes. The compatibility of PIC components for data communication and FBG sensing, enables the full integration of their functionalities on a single chip. In view of the trends towards miniaturization, the system concept combines many multiple features into a single high reliable PIC based system and subsequently highly applicable for multi-parameter sensing and datacommumication purposes.

Rolf Evenblij


8 9

MYRIADGATOR FOR AFFORDABLE AND HIGH PERFORMING DISTRIBUTED FBG SENSING

One of the key advantages of fiber sensing compared to electronics sensors is the ability to integrate multiple measurement points down a single fiber line. Probing particular FBG sensors is done by allocating a certain frequency bandwidth for each sensor, of which there is limited total window available (e.g. 8 for a gator). Sensor multiplexing in one fiber can, however, also be obtained in the time domain. A new method has been demonstrated to work with our standard gator architecture by the addition of a time-modulated optical amplifier in line between the gator and the sensor array. This time-domain multiplexing allows for tens to hundreds of unique sets of FBGs to be interrogated in a single fiber consecutively, vastly extending the range of sensors into the thousands that can be analyzed with a single interrogation system.

This highly demanded system will soon become available as the MyriadGator, of particular interest to distributed sensing applications requiring many sensors for instance for thermal mapping and security monitoring.

Thijs van Leest

[email protected]

FORCE TRANSDUCER FOR CARDIAC INTERVENTIONS

The difficult relation between electricity and the human body introduces a

lot of complexities into designing high-tech medical instruments. Especially

instrument used in cardiac inventions. Fiber optic sensing, however, uses

light for measurement and is therefore highly adequate for instrumentation

for use in cardiac interventions. Together with medical partners, Technobis

developed a force transducer to be used during cardiac ablations.

The contact between the catheter and the cardiac tissue introduces strain, stress and displacement in the fiber optic sensors and can be calculated into a force. Combines with a three axis design, the direction of the force can also be determined.

Recordings of a controlled force on the fiber tip resulted in an displacement accuracy of 1 nanometers, equivalent to 10 mili Newtons.

Julius Zonneveld

Development [email protected]

10 11

HAPTIC FEEDBACK WITH FIBER OPTIC SENSING

Most of the surgical interventions are performed via laparoscopic surgery.

A hollow tube is inserted through the skin of a patient. Through this hollow

tube, surgical tools are inserted toward the affected tissue. This technique

results in a quick recovery and low scar tissue for the patient. However, the

surgeon is not in direct contact with the tissue; doesn’t know how tight to grip

and thus creates unintentional damage.

The OptiGrip is a surgical tool with Fiber Bragg Grating imbedded in the tip. These FBGs respond to the stress and strain in the pincher that are translated to haptic feedback on the handle of the tool. In-vivo experiments with this tool resulted ‘feeling the heartbeat in the blood vessel through the handle bar’.

Julius Zonneveld


RF/MRI COMPATIBLE IN-VIVO TEMPERATURE SENSING

Diagnostic instruments are the tools MD’s use to acquire data about the patient. An important parameters is the body temperature, both externally on the skin and in-vivo. Especially during Hyperthermia and surgical interventions, the in-vivo body temperature is a parameter that needs continuous monitoring.

Disadvantage of electrical temperature sensors is the fundamental use of electric current, and the sensitivity to RF-sources (e.g. MRI). Fiber Bragg Gratings (FBG), are insensitive to RF sources and are therefore ideally to be used during in-vivo temperature monitoring in RF environment.

The SwitchedRefGator system from Technobis runs on the same principle as the Gator series; A reflected wavelength from an FBG is tracked over time using our spectrometer. Combined with an internal reference FBG, the recorded wavelength of the FBGs can be converted into an absolute temperature reading.

The SwitchedRefGator can integrate up to 7 optical fibers with each 8 FBGs (total 54 sensors). The FBGs are integrated in the optical fiber with a typical diameter of 0.25mm allowing for easy integration into a catheter of needle. The system can achieve a short-term v of 0.1°C (1-2 hr) and a long-term accuracy of 0.5°C (5-10 hr), with a resolution of 0.03°C.

Julius Zonneveld


12 13

MULTI-POINT BLOOD PRESSURE SENSING

Yearly 1.3 million people undergo an angioplasty treatment where a narrowed blood vessel (stenosis) in the coronary arteries is treated. Conventionally this diagnosis is made with X-ray imaging of the blood vessel in combination with a contract fluid put into the arteries. This contract fluid is highly visible on the x-ray images and indicates the level of blood flow reduction. Treatment is based on visual inspection by the cardiologist. Although trained in this type of procedure, unnecessary treatments are common. A method to quantify these stenosis (e.g. the blood flow reduction) lacks.

Fiber optic sensing has high potential in medical applications. An increasing number of parameters can be monitored with optical fibers. With the use of an FBG in a Microstructure Optical Fiber (MOF) blood pressure sensing becomes possible. The reflection of the FBG in the MOF contains two center wavelengths. Whereas temperature and strain causes an identical shift of these two peak, changes in pressure causes these peak to shift with different sensitivity; resulting in a change in spectral separation. This parameter, the peak difference, can be used for blood pressure sensing. In experiments at Technobis the pressure was changed from 0 to 1.4 bar resulting in a spectral separation between the two peaks of 1.6 pm per bar. The Technobis Gator platform allows this technology to be integrated in a guidewire for use in cardiac stenosis treatment for accuracies in the order of 1 mbar / 0.75 mmHg.

Julius Zonneveld


SHAPE SENSING FOR MINIMAL INVASIVE INSTRUMENTS

A biopsy needle is used to take a sample of tissue from a patient. It is

important to take a sample of the correct piece of tissue. In order to help

determining the position of the tip of the needle

FBG sensors for shape sensing can be integrated.

Three separate fibers with FBG sensors are embedded in a groove on the side of the needle. The grooves are made in a 120° configuration with respect to each other. When the needle is bend, the FBG’s on the inside will be compressed while the FBG on the outside will be elongated. This strain causes a change in the reflected wavelength of the FBG sensor. With the use of the Frenet-Serret formulas and the measured strain values, the 3D shape of the needle can be reconstructed. Because of the symmetric 120° configuration of the sensors, this principle is automatically compensated for temperature.

Julius Zonneveld


14 15

SHAPE SENSING WITH A MULTICORE OPTICAL FIBER

In this specific medial application, a multicore fiber is used as a shape sensor

in a catheter. A multicore has the advantage of being small and the fiber

itself is the complete shape sensor. The outer diameter of a multicore fiber is

identical to that of a single fiber, which is only 125μm.

A standard optical fiber has one core and since this core is located in the center it will not measure strain when a fiber is bend. In a multicore fiber typically 4 or 7 cores are present in a symmetric pattern around the center. Because of the different distances to the center, each core will experience a different strain when the fiber is bend. FBG sensor can be written in each of the cores.

With the use of a MultiGator system with synchronized read-out, all FBG sensors in the multicore fiber are measured simultaneously. With the measured strain values and the use of the Frenet-Serret formulas, the 3D shape of the fiber can be reconstructed. New developments are ongoing in this field with twisted multicores, this opens new possibilities to include torsion measurements with the same fiber.

Vincent Docter

[email protected]

HIGH RESOLUTION STRAIN MEASUREMENTS

ASML requires high resolution strain sensing in their lithography machine in

order to correct for nanometer vibration of the mechanics.

A scanning narrow-linewidth laser, aligned to a pi-shift FBG, is inserted into an on-chip unbalanced Mach-Zehnder interferometer (MZI), i.e. “PalawanGator”. The MZI functions as a wavelength tracker and can measure the optical power simultaneous; from this information a spectrum can be generated, and the FBG wavelength can be determined with high accuracy.

Even though the scanning laser is narrow linewidth laser, implying that a low wavelength noise during modulation, the linewidth ‘noise’ can cause a white noise floor when looking into non-wavelength corrected algorithms. With the PalawanGator these miniscule deviations can be measured and compensated for in the strain/temperature measurements. Strain values up to 0.2 nε can be measured, depicted by the power spectral density of the strain noise.

Michael Haverdings

[email protected]

16 17

HIGH RESOLUTION TEMPERATURE MEASUREMENTS

ASML required high resolution (mK) temperature mapping within the

lithography machine. As a research topic, ASML was investigating the

feasibility of a single fiber alternative to 100 electrical wires to accommodate

50 NTCs in a small surface area.

To achieve high resolution interrogation the complete assessment of every used component was required. Items considering FBG parameters (FWHM, reflectivity), SLD-noise, Electronics noise, and others, enabled a well-educated estimate of the final performance of the system.

The single fiber proved itself a more than suitable alternative for NTCs.

1. All 50 sensors can spectrally be resolved and therefore measured with 28 kHz sampling. 2. High resolution sensitivity was achieved: a FBG strain resolution (std) up to 25 ne with 28 kHz sampling.

Due to the fabrication quality of the FBGs there is an envelope in the reflectivity, consequently the same form of envelope is seen in the signal-to-noise of the FBG central wavelength.

3. And the NTC reference measurements showed that the FBGs have a very comparable temperature response curves. And even tend to have a shorter response time.

Michael Haverdings

[email protected]

Michael Haverdings

[email protected]

HIGH DYNAMIC STRAIN RANGE AND -RESOLUTION WITH FIBER LASER SENSOR

High resolution strain measurements is relevant for high Tech applications like lithography machines, electron microscopes, hydrophone applications. Using a fiber-laser as sensor enables highly sensitive (vibration) measurements. An active laser within a fiber is used as a sensor. The laser is a narrow linewidth FBG cavity within an erbium doped fiber. The erbium is stimulated with an external pump source and the cavity starts to lase on its central wavelength. When an external stimulation is present, like strain, the laser cavity changes accordingly. By measuring the output wavelength (shift) with the PalawanGator the strain is measured with high precision. At Technobis a noise floor of 0.46 nε 3σ with 200 kHz sampling over 0.01 sec was demonstrator, which is equivalent to 0.5 pε/√Hz. The noise performance of the fiber laser remains the same under applied strain of ~150 µε and is expected to remain over larger strain ranges. The high frequency noise is mainly limited by the dark noise / shot noise of the electronics, and within the low-frequencies the thermal behavior of the fiber-laser sensor is measured (1/f ). In other configurations the fiberlaser sensor was stimulated with an acoustic signal.

18 19

MULTI-PARAMETER SENSING

A Fiber Bragg Grating (FBG) is a periodic modulation of the refractive

index along a single mode fiber core. The periodicity results in reflection

of light waves that match the periodic spacing in wavelength, while other

wavelengths are transmitted unperturbed.

Due to environmental changes (temperature, strain, pressure etc.) the refractive index and grating period are influenced which result in a wavelength shift of the reflected peak. Precise monitoring of the spectral peak positions can thus be used for sensing. In many applications it is desirable to distinguish between physical contributions to the Bragg shift, e.g. Temperature and strain, or Temperature and pressure. Different approaches can be taken towards separation, such as the use of an additional FBGs in strain-free condition for Temperature correction. However, multiparameter sensing is also achievable in single FBG sensors, by use of polarization maintaining (PM) fibers.

PM fibers have a stress-induced birefringence, resulting in splitting of a waveguide mode into two orthogonal waveguide modes. An FBG written in a PM fiber, allows separate interrogation of the FBG peak in the two polarization axes (fast and slow). The birefringence results into FBG peak splitting as the refractive index in both polarization differs by Δn. As a function of temperature or strain, the peaks shift differently, allowing for separation of variables.

Another version of multi-parameter sensing involves the separation between pressure and temperature. Instead of applying stress rods like in PM fibers, airy holes can be used in the fiber. As a function of pressure, a differential peak shift will occur, unlike with Temperature.

Thijs van Leest

[email protected]

WIND TURBINE MONITORING

Operation and maintenance (O&M) of offshore wind turbines is one of

the main cost drivers of offshore wind energy today. Condition based

maintenance, instead of corrective maintenance, is becoming more and more

a means to better control the O&M costs of wind turbines.

All current known monitoring techniques have in common that useful information is provided after the components start to degrade or fail. Degradation of components is strongly related to the loads introduced via the rotor blades. Therefore the partners in the LoadWatch project collaborate with the goal to finalize the fibre-optic load monitoring system (FOBM) and make it ready for commercial sales. Apart from load monitoring as input for condition based maintenance planning, the real time information can be used for e.g. individual pitch control (IPC), applied in order to reduce the loads on the blades.

Already ongoing measurement campaigns in wind turbines using the desktop interrogator and prototype sensor design substantiate the tremendous usefulness of the load monitoring data. Current efforts focus on delivering a fully industrial validated product with EtherCAT data-interface and integrated wavelength reference. This ruggedized, small footprint interrogator is IP60 rated, shows outstanding stability and is already commercially available by the end of 2018.

In combination with the fully validated sensor rig a 6 months field test is started in 2019 proving the real time information usefulness for condition based maintenance and IPC, which results in a reduction of cost of energy of 0.4% in offshore wind!

Jantina Wijpkema


20 21

WIND TURBINE BLADE MONITORING

Developments in offshore wind are driven by an increasing size of the wind

turbine power per unit. As a consequence the turbine blades become larger

and more flexible. Designing these blades, current tools have insufficient

accuracy showing up to 17% variations in stiffness.

Ideal in harsh outdoor environments such as offshore wind is the use of light weight fibre optic sensing technologies. The ease of handling, high speed accurate data acquisition, small footprint, low price and minimum impact from the sensors on the material surface (aerodynamics) makes fibre optic sensing superior to the use of conventional strain gauges or for example visual monitoring using cameras.

The SwitchedGator can log up to 120 optical Fibre Bragg Grating sensors divided over 15 channels using an optical switch allowing for channel multiplexing over different fibres with a sampling rate of >19 kHz per channel and a measurement frequency over 15 channels of up to 70 Hz.

A feasibility study is performed modelling the wind turbine blade and the desired accuracy to determine to optimum amount and placement of the optical sensors. Extrapolating the modelling results onto a real-life blade test proved that optical point-sensing accurately records the in-plane, out-of-plane and torsional deformations in a wind turbine blade. Therefore the SwitchedGator and optical measurement system are prepared for actual installation on a wind turbine starting a field-test in a wind farm!

Jantina Wijpkema


CRASH TESTING

Crash tests are a crucial factor in passive safety throughout the automotive

industry. They give manufacturers and OEMs in-depth knowledge about the

structural and energy absorption behavior of vehicles, their components and

the vehicle occupants. This demonstrator project focused specifically on the

integration of a measurement system to perform dynamic response analysis

of a crash dummy rib deformation during impact.

An optical fibre is installed on the rib, equally deviding eight optical sensors over the circumference of the rib. The Gator is used to measure the deformation induced wavelength shifts. From this information the off axis strain is calculated and together with the known distance to the neutral axis of the material, the bending radius is derived to reconstruct the shape of the rib.

The rib deformation demonstrator is finalized by combining the design and the shape reconstruction algorithm into a dedicated visualization software capturing both real-time deformations and high-speed impacts. Full system tests substantiate the actual compression of the rib of e.g. 20mm is accurately recorded by the dedicated software.

This successful proof of concept is ready for ruggedization and integration into a crash test dummy for continuous real-time deformation monitoring during impact!

Jantina Wijpkema


22 23

LUXURY YACHT MONITORING

Luxury yachts, just like daily used cargo ships, undergo tremendous hull

stresses even when not in use. Looking at a yacht having a steel hull the

sunny side could become >10mm longer compared to the shadow side of the

ship. Monitoring ship deflections for safety guarantees and condition based

maintenance is therefore a must in the nautical industry.

Safety guarantee should be realized avoiding bulky measurement systems, making the use of fibre optics an easy choice. The light weight optical sensors in combination with the SwitchedGator with multichannel sensor recording options, allows for onboard data processing, storage and remote access to filtered data.

The hull of both port and starboard side are equipped with multiple optical sensors at two decks. Therefore not only both sides of the ship can be compared, but also different levels of the same side. Sea trials already proven the use of the SwitchedGator in combination with fibre optic sensors for safety monitoring and condition based maintenance!

Jantina Wijpkema


DOWNFORCE AND VIBRATION MEASUREMENTS IN RACE CARS

We demonstrated the measurement capabilities of the Gator for racecar

applications by monitoring the downforce of the rear wing of a racecar.

Currently only FEM analysis is used to indicate the value of downforce, no

actual reference measurements have been performed before to our knowledge.

A single string of fiber with 8 FBGs was embedded on top of the rear wing and then shielded with laminate foil. 2 FBG sensors where embedded without adhesive with the aim for temperature monitoring.

Using the shape reconstruction algorithm different vibration modes along the length dimension of the rear-wing can be visualized. Each plot is a snapshot of a 24 msec period, during the test sequence. With a high wind-velocity a rear wing deflection is measured and in a test bench the deflection has been related to a downforce. The measurements with FBG sensors and our standard Gator provided data at 5 kHz (can go up to 19.2 kHz) and provided new insights in the vibration modes and downforce behaviour of the rear wing of a racecar.

Jantina Wijpkema


24 25

SHAPE RECONSTRUCTION FOR STRUCTURAL DEFORMATION

FBG sensing with Integrated Photonics can well be used for Structural Health

Monitoring for various structures based on the temperature-compensated

strain levels. By taking the advantage of the high sample rate of our Gator

product family, with given structural information and the measured strain

level, it becomes possible to capture, analysis, and reconstruct the deformed

shape of the monitored structure in high-speed (52 μs/sample).

Technobis has been involved in many projects and experiments where stain measurements were used to obtain shape and vibration information:

1. Large buildings2. Airplane wings3. Helicopter blades4. Vibration on composite panels5. Etc…

Based on the measured strain level and given structure information, we can apply Frenet-Serret formulas to reconstruct the shape of the deformed structure. In addition, by arranging FBG strain sensors as a Rosette strain gage, the bending and torsional deformation of the structure can be monitored simultaneously.

Matt Yuan


UNDERWATER SHAPE SENSING

The DeepGreen500 European project offers a solution for harvesting energy

from tidal and ocean currents, in harmony with marine eco system, with a

low average cost of energy (COE). In this collaboration project with Minesto a

500kW tidal power plant in form of a “flying” kite tethered to the sea floor is

developed.

Integrated photonics sensing technology is used in the realization of a monitoring system for tracking the kite’s movements by means of implementing a shape sensing system inside the tether. Dedicated designed strips can hold up to five optical sensors, four measuring deformation induced wavelength shifts (strain) and one measuring temperature. Using the strain information, the bending radius of the strip is calculated. Interpolation of the bending radius in between multiple strips result in an accurate shape reconstruction of the 26m tether length. Any possible thermal influences can be corrected for using the temperature recordings.

Such application requiring multiple optical fibres the SwitchedGator is ideal to use. Multiplexing up to 15 channels with data acquisition of >19kHz per channel, allows for easy real time shape reconstruction in combination with a dedicated software.The full system tests have proven the system functionality in lab environment. Therefore the system is currently prepared for a real deep-sea test trial in 2019!

Jantina Wijpkema


26 27

Disclaimer: The products described within the catalog are subject to change by Technobis Fibre Technologies any time without notice.

Technobis tft-fosPyrietstraat 2, 1812 SC Alkmaar

The Netherlands

P.O. Box 1089, 1810 KB AlkmaarThe Netherlands

+31 (0) 72 3020040 [email protected]

APPLICATION HANDBOOK - Technobis

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