Fiber Optic Strain Sensor Vibration Separation for Detection of Seeded Faults in Rotorcraft Transmissions

2008 ◽  
Author(s):  
Joseph D. Coker ◽  
Darryll J. Pines ◽  
Paul D. Samuel ◽  
Jason Kiddy
Keyword(s):  
Fiber Optic ◽  
Local Strain ◽  
Diagnostic Methods ◽  
Fiber Optic Sensor ◽  
University Of Maryland ◽  
Planetary Gearbox ◽  
Additional Processing ◽  
Increased Sensitivity ◽  
Fiber Optic Strain Sensors ◽  
Helicopter Transmission

This paper presents a refined methodology for performing helicopter transmission anomaly detection through the use of vibration separation techniques applied to the output of a fiber optic sensor array. Fiber Bragg grating (FBG) sensors—distributed about the exterior of a planetary gearbox annulus—record the local strain response of the annulus surface due to tooth-mesh interactions. These strain profiles are collected for a number of loading conditions both with and without seeded faults. The profiles are separated and synchronously averaged to illustrate the effect of damage to planetary gears on local strain variation. Results of experiments conducted on the University of Maryland Transmission Test Rig (UMTTR) are included. Additional processing and comparison to traditional vibration-based diagnostic methods indicate the potential for increased sensitivity to damage of such a system and the feasibility of fiber optic strain sensors for in situ health and usage monitoring.

Fiber Optics for Evaluation of Pavement Reinforcement Materials in Resisting Reflection Cracking

1996 ◽  
Vol 1536 (1) ◽  
pp. 140-145 ◽  
Author(s):  
Mohamed Abdel-Mooty ◽  
El-Hussein H. Mohamed ◽  
Joseph Haddad
Keyword(s):  
Fiber Optics ◽  
Asphalt Concrete ◽  
Fiber Optic ◽  
National Research Council ◽  
Fiber Optic Sensor ◽  
Laboratory Evaluation ◽  
Reflection Cracking ◽  
Fiber Optic Strain Sensors ◽  
Pavement Reinforcement ◽  
Asphalt Concrete Pavement

A major maintenance problem of pavement is the reflection cracking of pavement overlays at the location of joints and cracks in the underlayers. Pavement reinforcement materials (PRM) are used to reinforce the asphalt concrete (AC) overlay to delay reflection cracking. Assessing the effectiveness of PRM in limiting reflection cracking can be achieved by direct measurement of strain distribution within the PRM and AC overlay. A fiber-optic sensor is the only alternative that is compatible with the fiberglass structure of the PRM used in this study and, therefore, is used to measure strain within the PRM. A program of investigation, developed at the Institute for Research in Construction of the National Research Council Canada, aims at studying the state of stress leading to joint opening in pavement layers and assessing the effectiveness of PRM in reducing such cracks through monitoring the performance of PRM using embedded fiber-optic strain sensors. The investigation involves both laboratory testing and long-term field monitoring of instrumented road section. The instrumentation aspect of the laboratory evaluation of PRM effectiveness using embedded fiber-optic sensors is described. An instrumentation procedure is developed that includes sensor mounting and embedding, mechanical protection, calibration, and data acquisition system. The performance of the developed monitoring system in asphalt concrete pavement specimens is assessed in controlled laboratory conditions.

scholarly journals Versions of Fiber-Optic Sensors for Monitoring the Technical Condition of Aircraft Structures

2018 ◽  
Vol 4 (12) ◽  
pp. 2895 ◽  
Author(s):  
Nikolai Lvov ◽  
Stanislav Khabarov ◽  
Aleksander Todorov ◽  
Aleksander Barabanov
Keyword(s):  
Fiber Optic ◽  
Technical Condition ◽  
Fiber Optic Sensors ◽  
Strain Sensors ◽  
Fiber Optic Sensor ◽  
Temperature Deformation ◽  
Experimental Comparison ◽  
Polymeric Composite Material ◽  
Advantages And Disadvantages ◽  
Fiber Optic Strain Sensors

It is necessary to monitor the technical condition of various equipment due to the increased requirements for the safe operation of complex technical objects, such as bridges, structures, aircraft, cars and others. Monitoring systems based on the use of fiber-optic sensors measuring various physical quantities (temperature, deformation, pressure, vibration, etc.) are increasingly used for these purposes, since they have significant advantages over electrical sensors. The aim of the study is to compare the various options for the implementation of fiber-optic strain sensors to monitor the stress-strain state of the monitored object. A theoretical and experimental comparison of three types of fiber-optic sensors was carried out: on a mechanical fastener, sensors glued to the surface of a monitored design, and sensors embedded in a polymeric composite material at the stage of its manufacture. The requirements for the elements of the onboard systems of the aircraft according to the document “Environmental conditions and test procedures for airborne equipment QR-160D” are selected as comparison parameters. To assess the characteristics of various types of fiber-optic strain sensors, comparative bench mechanical and environmental tests were carried out. According to the test results, it was concluded that each type of sensor has its own advantages and disadvantages in comparison with each other, and in general, each of them can be used to create new standard systems for structural health monitoring of various units and structures of the aircraft (SHM systems). Also, the article proposed a new method of gluing a fiber-optic sensor to a controlled structure. This method - the use of specialized equipment, providing convenience and stability of gluing.

Hydrostatic Fiber Optic Liquid Level Sensor with position sensitive detector

Metrologiya ◽  
2020 ◽  
pp. 38-51
Author(s):  
V. N. Astapov ◽  
I. N. Kozlova
Keyword(s):  
Fiber Optic ◽  
Effective Area ◽  
Raw Material ◽  
Position Sensitive Detector ◽  
Fiber Optic Sensor ◽  
Liquid Level ◽  
Problem Solution ◽  
Sensitive Detector ◽  
Position Sensitive ◽  
Triangulation Sensor

This article presents the rationale and methodology for developing an intrinsically safe device, namely, a hydrostatic fiber optic sensor with a position-sensitive detector for monitoring the level of oil products in large-capacity tanks at oil depots and during pumping in a raw material warehouses. This device suitable for continuous monitoring of the liquid level, based on the measurement of a hydrostatic column of liquid with automatic offset of changes in the density of the liquid. Offset is carried out by means of a displacer (a fully submerged float), inside which a housing with a position-sensitive detector (PSD) is integrated. Theoretical validation of the bellows suspension usage for a displacer is given. During filling a container with a liquid whose level is measured, liquid bellows, the movement of which is recorded by an optical triangulation sensor using the reflected infrared ray incident on the bottom of the bellows. The principle of the triangulation sensor operation is based on the geometric properties of the triangles. The pulses of infrared radiation come through a fiber optic cable. In order to measure the movement of the surface (the bottom of the bellows) by measuring the movement of the reflected beam, a position-sensitive detector is used, which is located in a remote controller. In this device for the intrinsic safety problem solution, optical inputs of a fiber optic flat cable are located in the active zone of the sensor, which is connected to the optical inputs of a position-sensitive detector, operated on the principles of photoelectric effect. The light spot moving along the sensitive zone and converted by the detector into a one-dimensional signal proportional to the distance to the object. hydrostatically applies pressure over the entire effective area of the measuring

Fiber Optic Sensor for Measuring Rotation

2011 ◽  
Vol 14 (4) ◽  
pp. 66-72 ◽  
Author(s):  
S.M. Al-Hilly ◽  
◽  
Z. E. Khaleel ◽  
A.F. Alrubaye ◽  
◽  
...  
Keyword(s):  
Fiber Optic ◽  
Fiber Optic Sensor ◽  
Optic Sensor

scholarly journals Sensing, Actuation, and Control of the SmartX Prototype Morphing Wing in the Wind Tunnel

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 107
Author(s):  
Nakash Nazeer ◽  
Xuerui Wang ◽  
Roger M. Groves
Keyword(s):  
Wind Tunnel ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Experimental Testing ◽  
Single Mode ◽  
Fiber Optic Sensor ◽  
Sensor Data ◽  
Random Errors ◽  
Morphing Wing ◽  
Actuator Dynamics

This paper presents a study on trailing edge deflection estimation for the SmartX camber morphing wing demonstrator. This demonstrator integrates the technologies of smart sensing, smart actuation and smart controls using a six module distributed morphing concept. The morphing sequence is brought about by two actuators present at both ends of each of the morphing modules. The deflection estimation is carried out by interrogating optical fibers that are bonded on to the wing’s inner surface. A novel application is demonstrated using this method that utilizes the least amount of sensors for load monitoring purposes. The fiber optic sensor data is used to measure the deflections of the modules in the wind tunnel using a multi-modal fiber optic sensing approach and is compared to the deflections estimated by the actuators. Each module is probed by single-mode optical fibers that contain just four grating sensors and consider both bending and torsional deformations. The fiber optic method in this work combines the principles of hybrid interferometry and FBG spectral sensing. The analysis involves an initial calibration procedure outside the wind tunnel followed by experimental testing in the wind tunnel. This method is shown to experimentally achieve an accuracy of 2.8 mm deflection with an error of 9%. The error sources, including actuator dynamics, random errors, and nonlinear mechanical backlash, are identified and discussed.

scholarly journals Fiber optic sensor based on fluorescence quenching for heavy metal detection

2020 ◽  
Author(s):  
Yadira A. Fuentes-Rubio ◽  
Rene F. Dominguez-Cruz ◽  
Oscar Baldovino-Pantaleon ◽  
Carlos Ruiz-Zamarreno ◽  
Francisco J. Arregui
Keyword(s):  
Heavy Metal ◽  
Fluorescence Quenching ◽  
Fiber Optic ◽  
Fiber Optic Sensor ◽  
Heavy Metal Detection ◽  
Optic Sensor ◽  
Metal Detection
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