Simplified compact phased array method for localization of multiple defects in structural components


Structural systems used in different fields such as mechanical, aerospace and civil are susceptible to various failures, which may occur from either known or unknown causes. In an approach to eliminate or minimize such failures which many times result in accidents, various methods have been put in place to help in monitoring the functionality and conditions of such structures. Through these methods, it is possible to detect defects and damages in structures before their failures.

Guided-waves is a technique for structural health monitoring system that has been widely used over the times in several fields. They have high sensitivity and can propagate long distances as well as thick walls. They have helped in detection and localization of the defects within structures.

Although numerous array systems can be used in structural health monitoring systems depending on the nature of the structure and type of information required, most of them require additional studies to improve their reliability while the cost and complexity reduced for commercialization. For example, phased arrays which employ the principle of radar systems depends on a real beam for scrutinizing the structural surfaces for damages from the outputs of all the transducers used. Although it has several advantages over other conventional systems such as short inspection time duration and much higher signal to noise ratio, there is still need to further improve the system and eliminate some of the expensive electronic devices necessary for its operation.

For instance, the structural defects localization has been continuously improved over the past years, as demanded by the continuing growth of more complex structural components due to technological advancements. As a result, various array configuration requires different analysis algorithms for reliable and accurate monitoring of structural components whether complex or simple. In most cases, such configuration requires the use of many sensors and actuators.

Professor Ibrahim Tansel and his research group at Florida International University: Ph.D. students Amin Baghalian, Shervin Tashakori and Dr. Dwayne McDaniel together with Dr. Volkan Senyurek  who letter moved to University of Alabama proposed a simplified, compact phased array method for localization of multiple defects in structural components. Their work is published in the journal, Journal of Sound and Vibration.

The proposed technique uses only three piezoelectric elements.  Two of them works as exciters while the third one  monitors the reflected surface waves.  The data collection is completed with three tests in each a different piezoelectric element is used as sensor.  At each test 60˚degrees in the front and 60˚degrees at the back are scanned.  The received information is processed by using the modified total focusing method (TFM) and interface information for identification of the exact location of the cracks.

From the results obtained by the authors, it was observed that their proposal is viable for locating both single and multiple defects in structural components with high accuracy and precision.

Compact phased array approach is far much better than other methods due to their simplified nature. Proposed approach only requires three piezoelectric elements working together hence eliminate the need for several devices such as multiplexers and pulses as compared to its counterparts. Furthermore, it does not require high voltage supply for maintaining and running of its components because it creates beams in the selected directions only. It also requires short time for processing the collected data. The authors are optimistic that this approach can be implemented in the aerospace applications.

It is worth noticing that the research team just recently developed first structural health monitoring system which doesn’t use any sensors, computers or user interface to detect cracks and loose bolts. The Sensorless Structural Health monitoring (SSHM) systems excite the structure with such custom designed signals that a noise or verbal message will be created if there is a nonlinear damage such as crack or loose bolt.  This innovative approach may be implemented to the commercial products below $10 cost and let the masses to use the SSHM in many daily products from washers to toys.

Localization of multiple defects using the compact phased array method. Advances in Engineering

Simplified compact phased array method for localization of multiple defects in structural components. Advances in Engineering

compact phased array method. Advances in Engineering

compact phased array method for localization of multiple defects in structural components. Advances in Engineering

About the author

Volkan Yusuf Senyurek is post-doctoral researcher in Department of Electric and Computer Engineering at the University of Alabama. He received his BS, MS, and PH.D degrees all in electronics and communication engineering from Marmara University in 2003, 2007, 2013, respectively. After he got Ph.D, he worked as assistant professor at Marmara University until October 2015. Between October 2015 and June 2017, he worked as a Post-doctoral researcher in Department of Mechanical and Materials Engineering at Florida international University. In June 2017, he joined Department of Electric and Computer Engineering at University of Alabama as Post-doctoral researcher. Currently he is working on automated smoking pattern recognition via IMUs.

His research interests are structural health monitoring, sensorless SHM systems, biomedical signal processing, wearable sensors and fiber optic sensors. He has teaching experience on electronic circuits, communication, test and measurements, fiber optic and applications, and microcontrollers.

About the author

Amin received his BS and MS in mechanical engineering from University of Mazandaran (the later Babol Noshirvani University of Technology). After that, he joined Florida International University (FIU), mechatronics lab. His research focus was on defect detection and structural health monitoring of metallic pipes and plate-like structures. During his PhD studies, he was involved in the development of novel structural health monitoring methods using a variety of system identification, signal processing, and data classification techniques.

He also served as a lecturer for the manufacturing course in the Mechanical Engineering Department of FIU for three years. Amin received his PhD in mechanical engineering-design and manufacturing in Dec 2017.  He currently works in the research and development center of Phillips 66 company.

About the author

Mr. Shervin Tashakori is a research scientist and PhD students at the Mechanical & Materials Department of the Florida International University.  He plans to receive his Ph.D degree in August 2018.  He started his PhD study after receiving his B.S. in Electrical and his MS in Mechatronics Engineering from QIAU in Iran.

Mr. Tashakori has been working on the implementation of Structural Health Monitoring (SHM) techniques for identification of the defects of carbon fiber reinforced epoxy composites. He joined Applied Research Center (ARC) of Florida International University in 2015 and worked as a research scientist for two years. During his time at ARC, he worked on an FFA funded project regarding the effect of surface contamination on composite bond integrity and durability. He also had the opportunity to be a teacher assistant for some courses such as Smart Machine Design and Development, Introduction to Mechatronics, Introduction to CAD/CAM, Nonlinear Finite Element Analysis and Airplane design at Mechanical & Materials Department of the Florida International University.  He has also worked on the design, manufacture and programming of different types of robots and quadcopters during his master in mechatronics engineering.

About the author

Dr. McDaniel is a Principal Scientist at FIU’s Applied Research Center (ARC).  His responsibilities include designing and directing applied research related to mechanical and aerospace applications for the federal government and the private sector. He is also the Project Manager for the high level waste (HLW) projects within the Co-operative Agreement between the Department of Energy and FIU.  Dr. McDaniel has over fifteen years of experience in mechanical and aerospace engineering and is a registered professional engineer in the State of Florida. He received his bachelor’s degree in aerospace engineering from the University of Florida and also received his Masters and Ph.D. from the same university in engineering mechanics.

Dr. McDaniel has been the principal investigator on a number of projects funded by federal agencies that include DOE-NETL, NOAA, FAA, ONR, and ARO.  These projects range from developing reduced order models in computational fluid dynamics codes to conducting structural analysis of marine structures.  As the manager of the HLW projects, he directs funded research (~$1M/year) that includes the development of robotic inspection tools, evaluation of sensors for erosion and corrosion applications and testing of polymers that have been aged with multiple stressors.

About the author

Dr. Ibrahim Tansel received his Ph.D. in 1986 and has been teaching at the universities since his graduation.  Dr. Tansel worked on automation of manufacturing operations, modeling micromachining, interpretation of X-ray images, tracking electromagnetic objects and structural health monitoring (SHM).  He used many system identification tools including time series analysis, neural networks, genetic algorithm, optimization tools and wavelets.  He has over 60 journal papers.  Dr. Tansel worked for NAVY, NASA and Air Force for 13 summers.

Dr. Tansel taught many courses including Manufacturing, Mechatronics, Entrepreneurship and System Identification.  Dr. Tansel received the Outstanding Young Manufacturing Engineer Award in 1992 from Society of Manufacturing Engineers, and received two research and one teaching awards from the Florida International University.  He is Fellow of the ASME.

Dr. Tansel’s group recently developed the heterodyne method for detection of defects which changes the characteristics of the structures from linear to nonlinear.  Cracks, loose bolts, delamination and debonding may be detected with these methods without any reference or baseline.  In addition, they have developed the first sensorless SHM system.  Plates and washers create a noise or may give verbal messages if any bolt is loosened or a crack is initiated.


Senyurek, V., Baghalian, A., Tashakori, S., McDaniel, D., & Tansel, I. (2018). Localization of multiple defects using the compact phased array (CPA) methodJournal of Sound And Vibration, 413, 383-394.

Amin Baghalian, Shervin Tashakori, Volkan Y. Senyurek, Muhammet Unal and Ibrahim N. Tansel. Novel Approaches for Loose Bolt Detection With and Without Sensors Using Heterodyning Effect. IWSHM 2017.

Sensorless Talkative Structural Health Monitoring, (watch movie)


Go To Journal of Sound And Vibration

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