online health monitoring of aircraft wing made of ...figure 12.defect location estimation using...

International Journal of Innovative Research in Information Security (IJIRIS) ISSN: 2349-7009(P) Issue 05, Volume 04 (May 2017) SPECIAL ISSUE www.ijiris.com ISSN: 2349-7017(O)

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Online Health Monitoring Of Aircraft Wing Made Of

Composite Material

Rakshith Kumar B R1 1UG Student, Department of Mechanical Engineering,

Jyothy Institute of Technology, Bangalore-560082, India. Abstract: Online Health Monitoring technology is a revolutionary method of determining the integrity of aircraft structures, and is increasingly being evaluated by the aerospace industry as a possible method to improve the safety and reliability of aircrafts and thereby reduce their operational cost. This paper briefly introduces general perspectives of commercial aircraft company on online health monitoring systems so that they can be applied on commercial aircrafts in real world and play significant roles in commercial aviation maintenance programs. Major challenges for implementing a online health monitoring system in the real world are also discussed, including airworthiness compliance, miniaturized lightweight hardware, self-diagnostics and an adaptive algorithm to compensate for damaged sensors, reliable damage detection under different environmental conditions.

Keywords: Composite Materials, Aircraft, Fiber Optic Sensors, Accelerometers, IOT OBJECTIVES: Understand the concept of structural health monitoring and associated terminologies. To know about different types of damage detection techniques. Detection of internal flaws using various methods is important from safety point of view.

I. INTRODUCTION:

Online health monitoring defined as a system with the ability to detect and interpret adverse “changes” in a structure in order to improve reliability and reduce life cycle costs. The greatest challenge in designing a OHM system is knowing what “changes” to look for and how to identify them. The characteristics of damage in a particular structure play a key role in defining the architecture of the online health monitoring system. In recent years high percentages of advanced composite materials are integrated into the primary flight structures of aircraft. Example, over 50% of the structural components of the Boeing 787 and Airbus are made of composite materials rather than conventional aluminum alloys.

Figure 1.Use of composite materials in the Boeing 787.

COMPOSITE WINGS The critical element of aircraft is the design of the wings. Several factors influence the selection of material of which strength allied to lightness is the most important. Composite materials are well known for their excellent combination of high structural stiffness and low weight.

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Because of higher stiffness-to-weight or strength-to-weight ratios compared to isotropic materials, composite laminates are becoming more popular. Composite structures typically consist of laminates stacked from layers with different fiber orientation angles.

DAMAGE DETECTION TECHNOLOGIES: 1. Fiber Optic Sensors 2. Electromechanical Impedance 3. Acoustic Emissions 4. Ultrasonic guided wave method 1. Fiber Optic Sensors Fiber optic sensors developed to date of interest for structural health monitoring can be categorised into three main types: interferometric, grating-based and distributed. Apart from being based on diverse measuring principles, these three types of sensors provide different spatially-resolved measurement capabilities. In general, interferometric sensors are suitable for single-point detection, while grating-based and distributed sensors can be used for quasi-distributed and distributed measurements respectively. Each category includes a variety of concepts that have been employed for different measures and applications. Figure 2 gives a schematic overview of the major sensors types available.

Figure 2. Types of fiber optic sensors.

FIBER BRAGG GRATING (FBG) SENSOR INSTRUMENTATION: The use of FBGs in composites has shown great interest during the late 20thcentury. FBGs sensing principle enquires light source to sense the physical phenomenon. The basic working principle of FBG is by reflecting a specific wavelength of the emitted light source depending on the Bragg properties. As the optical fiber is in tension, the gap of the Bragg gratings will be wider and vice versa when the optical fiber is in compression.

Figure 3. Fiber Bragg Grating’s principle of operation.

Figure 4.Optical fibersection (a) unidirectional; (b) cross-ply and (c) woven fabric.





Figure 5. (a)Typical scheme of wing box,(b) deployment of the optical fibres in the structure.

II. ELECTROMECHANICAL IMPEDANCE The Electromechanical impedance method couples the mechanical impedance of the subject structural material to the electrical impedance measured by a piezoelectric wafer active sensor (PWAS). The PWAS is used as a high frequency modal sensor. The peaks and valleys of the real part of the electrical impedance measured between the sensor electrodes reflects the mechanical response spectrum of the structure. Damage can be detected through spectral changes characterized by simple statistical equations or probabilistic neural networks. applications for spot welds, bonded joints, composite overlays for the infrastructure, and aging aircraft panels.

Figure 6. Electromechanical actuator.

III. ACOUSTIC EMISSION METHOD Acoustic emission (AE) can be defined as the sudden release of localized strain energy in the form of transient elastic wave, due to a distortion or change in the structural integrity of material. Many Acoustic emissions arise during damage processes within structures. These AEs are referred to as primary ones while the secondary AEs are the others induced from external sources, such as impacts. AE phenomena could appear evidently even when a structure is in microscopic-level damage status, which provides the possibility for defect forecasting and real-time monitoring.

Figure 7. Acoustic emission method.

IV. ULTRASONIC GUIDED WAVE METHOD Ultrasonics and radiography are broad classifications of methods widely used for nondestructive evaluation and testing. These methods are less applicable to SHM due to equipment requirements, that is, many of the methods are best suited for a dedicated laboratory and it is impractical to permanently affix the necessary instrumentation to the structure. One major exception is ultrasonic guided waves that can be generated by lightweight piezoelectric transducers permanently affixed to the structure. Guided waves have strong potential for SHM because they enable monitoring of a large volume of material from a single location. The structure must have boundaries or interfaces that make it a wave guide and channel ultrasonic energy in certain directions.





Figure 8. Surface mountable PZT sensor

Figure 9. PZT sensors mounted on wing panel

Figure 10. working of ultrasonic guided wave method.

Figure 11. wireless inspection waveform of a specimen.





V. TOMOGRAPHY In guided wave tomography, an array of PWAS is mounted around the area to be monitored as shown in Figure 12. Guided waves are sent and received from each PWAS using the pitch-catch approach. Signal features are selected and analyzed to create a computed tomographic image. Due to the multimode nature of guided waves there are a broad range of candidate features for damage detection. The reconstruction algorithm accounts for wave scattering and reflections from damage using a probabilistic method that results in the final tomogram being a superposition of ray ellipses.

Figure 12.Defect location estimation using tomography.

II. COMMUNICATION THROUGH IOT

Aircraft health monitoring system using IOT. Which will send the health status in real time to the base station and also predict product reliability. Basically the idea is to replace a black box in an Aircraft with this system which continuously sends all the parameters read and computed by the sensors on board to the base station using IOT. It helps to make better decision in critical conditions and to keep record for further analysis. This system will also predict life span of an electronic device by using prognostic health management method.

Wi-Fi Implementation in Aircraft There are mainly two ways to create Wi-Fi in an air vehicle. a. Air to ground b. Satellite based c. Loon’s technology a. Air to Ground The towers are placed in a network these tower coverage cells are much bigger than those of the normal mobile towers used by other service provider. This use a version of CDMA, just like Verizon cell phones. Antenna is placed on the belly of the airplane, looks like a small fin. This network implementation cost is much cheaper than satellite based implementation. The accessible bandwidth is a few megabits per second per aircraft.

Figure 13.Air to ground network coverage.

b. Satellite based A satellite-based communications system operating at high data rates includes a plurality of satellites each having uplink and downlink antennas for transmitting and receiving a plurality of signal utilizing a plurality of spot beams to and from a plurality of coverage areas at a predetermined range of frequencies. The system also includes a plurality of user terminals for transmitting and receiving signals to and from the plurality of communications satellites at the predetermined range of frequencies and at one of the first plurality of data rates.





Figure 14.satellite based network.

c. Loon’s technology Balloons are used for many purposes but here it is used to create internet connection in remote or isolated areas. In this project network is created by making large balloons floating in stratosphere. Which act as a wireless station and provides internet service to the isolated areas in a cost effective manner.

III. CONCLUSION In this study, it is clear that online health monitoring system plays a vital role in the field of avionics and aerospace. Detection of internal flaws using various methods is important from safety point of view.Online health monitoring system monitors the conditions of components and reports to ground station via IOT, which is in real time and helps to take decision in critical situation. At the ground station the data is neatly organized date wise in Database. The data base can be used for future analysis. Analytical system which can predict the life time of components based on the monitored values is implemented at the IOT control terminal.

REFERENCES

[1]. X. P. QINGCurrent Aerospace Applications of Structural Health Monitoring in China 2005. [2]. Xiaoliang Zhao Active health monitoring of an aircraft wing with embedded piezoelectric sensor/actuator network

2007. [3]. Qiu LeiDesign and Experiment of PZT Network-based Structural Health Monitoring Scanning System 2009. [4]. Shabeer KPOptimization of Aircraft Wing with Composite Material, India 2013. [5]. Jian CaiStructural Health Monitoring for Composite Materials, China. [6]. E Vorathin Real-time monitoring system of composite aircraft wings utilizing Fiber Bragg Grating sensor 2016. [7]. Cliff J. Lissenden Structural Health Monitoring of Composite Laminates Through Ultrasonic Guided Wave Beam

Forming.


online health monitoring of aircraft wing made of ...figure 12.defect location estimation using...

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