Dr. Umar Amjad Profile

Dr. Umar Amjad

Research Assistant and Teaching Assistant at Univ of Arizona

SPIE Involvement:

Author

Area of Expertise:

Non-Destructive Testing , Structure Health Monitoring , Guided Waves , Phase sensitive Acoustic Micsroscopy , Instrumentation

Publications (24)

Proceedings Article | 9 May 2024 Presentation + Paper

Numerical modeling with experimental verification investigating the effects of nonlinearities on the sideband peak count-index technique and topological acoustic sensing

Guangdong Zhang, Bo Hu, Hamad Alnuaimi, Umar Amjad, Pierre Deymier, Keith Runge, Tribikram Kundu

Proceedings Volume 12951, 129511V (2024) https://doi.org/10.1117/12.3010021

KEYWORDS: Acoustics, Wave propagation, Aluminum, Numerical modeling, Modeling, Ultrasonics, Composites, Structural materials, Structural health monitoring, Interfaces

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A newly developed Nonlinear Ultrasonic (NLU) technique called sideband peak count-index (or SPC-I) measures the degree of nonlinearity in materials by counting the sideband peaks above a moving threshold line – larger the SPC-I value, higher is the material nonlinearity. In various published papers, the SPC-I technique has shown its effectiveness in Structural Health Monitoring (SHM) applications. However, the effects of different types of nonlinear phenomenon on the sideband peak generation is yet to be investigated in depth. This work addresses this knowledge gap and investigates the effects of different types of nonlinearity on the SPC-I technique. Three types of nonlinearities (material nonlinearity, structural nonlinearity and contact nonlinearity) are investigated separately through numerical modeling. Numerical modeling results show that the sideband peak values do not increase proportional to the input signal strength thus indicating nonlinear response, and different types of nonlinearities affect the SPC-I measurements differently. For the experimental verification a composite plate with impact-induced damage is considered for investigating the material nonlinearity and structural nonlinearity while a linear elastic aluminum plate is used to examine the contact nonlinearity between the transducers and the plate. The trends observed in the experimental observations matched the numerical model predictions. Monitoring damage growth in topographical structures – formed by inserting different materials in a matrix material is also investigated. In addition to the SPC-I technique an emerging acoustic parameter – “geometric phase change” based on the topological acoustics is also adopted for sensing damage growth in the topographical structures. The performance of SPC-I and topological acoustic sensing techniques as well as the Spectral Amplitude Difference (SAD) parameter for sensing the damage growth in topographical structures are compared and discussed.

Proceedings Article | 25 April 2023 Presentation + Paper

Acoustic source localization in composite plates using non-linear ultrasonic technique: SPC-I

H. Alnuaimi, U. Amjad, T. Kundu

Proceedings Volume 12488, 124880O (2023) https://doi.org/10.1117/12.2658631

KEYWORDS: Acoustics, Sensors, Composites, Ultrasonics, Source localization, Wave propagation, Engineering, Acoustic waves, Signal attenuation, Signal processing

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Proceedings Article | 19 April 2022 Paper

Inspection of steel tube welded joint using nonlinear ultrasonic technique

SeHyuk Park, Imraan Bokhari, Hamad Alnuaimi, Umar Amjad, Robert Fleischman, Tribikram Kundu

Proceedings Volume 12048, 120480V (2022) https://doi.org/10.1117/12.2611920

KEYWORDS: Ultrasonics, Nondestructive evaluation, Inspection, Wave propagation, Acoustics, Transducers, Frequency modulation, Defect detection, Damage detection, Waveguides

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Proceedings Article | 1 April 2019 Paper

Linear and non-linear analysis of composite plates using guided acoustic waves

H. Alnuaimi, U. Amjad, P. Russo, V. Lopresto, T. Kundu

Proceedings Volume 10972, 109720X (2019) https://doi.org/10.1117/12.2513783

KEYWORDS: Composites, Glasses, Waveguides, Ultrasonics, Acoustics, Ferroelectric materials, Transducers, Wave plates, Fourier transforms, Nondestructive evaluation

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Proceedings Article | 23 April 2018 Presentation + Paper

Effects of transducers on guided wave based structural health monitoring

Umar Amjad, Christopher Blase , Hamad Alnuaimi, Cac Dao, Juergen Bereiter-Hahn , Tribikram Kundu

Proceedings Volume 10600, 106000F (2018) https://doi.org/10.1117/12.2300841

KEYWORDS: Transducers, Waveguides, Acoustics, Ferroelectric materials, Wave propagation, Structural health monitoring, Ceramics, Ultrasonics, Fourier transforms, Image processing

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Proceedings Article | 27 March 2018 Presentation + Paper

Characterization of dental tissue by reflection and transmission ultrasound microscopy

Christopher Blase , Umar Amjad, Tribikram Kundu, Juergen Bereiter-Hahn, Maximilian Blume , Robert Sader

Proceedings Volume 10600, 106000W (2018) https://doi.org/10.1117/12.2300510

KEYWORDS: Teeth, Tissues, Ultrasonography, Acoustics, Reflection, Microscopy, Receivers, Signal detection

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Proceedings Article | 1 April 2016 Presentation + Paper

Advanced signal processing technique for damage detection in steel tubes

Umar Amjad, Susheel Kumar Yadav, Cac Minh Dao, Kiet Dao, Tribikram Kundu

Proceedings Volume 9805, 980511 (2016) https://doi.org/10.1117/12.2219417

KEYWORDS: Ferroelectric materials, Damage detection, Waveguides, Signal processing, Ultrasonics, Transducers, Received signal strength, Fourier transforms, Nondestructive evaluation, Structural health monitoring, Wave propagation

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SPIE Journal Paper | 21 September 2015

Detection and quantification of delamination in laminated plates from the phase of appropriate guided wave modes

Umar Amjad, Susheel Kumar Yadav, Tribikram Kundu

OE, Vol. 55, Issue 01, 011006, (September 2015) https://doi.org/10.1117/12.10.1117/1.OE.55.1.011006

KEYWORDS: Transducers, Aluminum, Wave plates, Waveguides, Wave propagation, Optical engineering, Electrodes, Feature extraction, Damage detection, Dispersion

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Proceedings Article | 23 March 2015 Paper

Guided wave technique for non-destructive testing of StifPipe

Umar Amjad, Susheel Yadav, Chi Nguyen, Mohammad Ehsani, Tribikram Kundu

Proceedings Volume 9438, 943805 (2015) https://doi.org/10.1117/12.2085571

KEYWORDS: Nondestructive evaluation, Continuous wavelet transforms, Waveguides, Signal processing, Wavelets, Glasses, Ferroelectric materials, Inspection, Wave propagation, Fiber reinforced polymers

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Proceedings Article | 9 March 2014 Paper

Effect of applied load on the nondestructive measurement of concrete strength

E. Mahmoudabadi, U. Amjad, T. Kundu, H. Saadatmanesh

Proceedings Volume 9064, 90641R (2014) https://doi.org/10.1117/12.2045336

KEYWORDS: Nondestructive evaluation, Ultrasonics, Velocity measurements, Transducers, Fourier transforms, Receivers, Time metrology, Ferroelectric materials, Cements, Transmitters

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Proceedings Article | 17 April 2013 Paper

Change in time-of-flight of longitudinal (axisymmetric) wave modes due to lamination in steel pipes

U. Amjad, Chi Hanh Nguyen, S. Yadav, E. Mahmoudabadi, T. Kundu

Proceedings Volume 8695, 869515 (2013) https://doi.org/10.1117/12.2009897

KEYWORDS: Waveguides, Wave propagation, Structural health monitoring, Ferroelectric materials, Fourier transforms, Nondestructive evaluation, Transducers, Dispersion, Ultrasonics, Signal processing

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Proceedings Article | 17 April 2013 Paper

Monitoring ageing of alkali resistant glass fiber reinforced cement (GRC) using guided ultrasonic waves

J. Eiras, U. Amjad, E. Mahmoudabadi, J. Payá, M. Bonilla, T. Kundu

Proceedings Volume 8695, 86950Q (2013) https://doi.org/10.1117/12.2008984

KEYWORDS: Glasses, Cements, Ultrasonics, Waveguides, Composites, Inspection, Acoustics, Nondestructive evaluation, Fourier transforms, Civil engineering

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Proceedings Article | 26 April 2011 Paper

Zero order mode selective excitation and highly resolved observations of lamb waves

A. Abdelrahman, U. Amjad, D. Jha, K. Tarar, W. Grill

Proceedings Volume 7984, 798413 (2011) https://doi.org/10.1117/12.880602

KEYWORDS: Signal detection, Transducers, Aluminum, Wave propagation, Ferroelectric materials, Signal to noise ratio, Acoustics, Sensors, Signal processing, Fourier transforms

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Proceedings Article | 18 April 2011 Paper

Lattice dynamics approach to determine the dependence of the time-of-flight of transversal polarized acoustic waves on external stress

K. Tarar, M. Pluta, U. Amjad, W. Grill

Proceedings Volume 7984, 79842R (2011) https://doi.org/10.1117/12.879315

KEYWORDS: Acoustics, Dispersion, Phase velocity, Chemical elements, Solids, Differential equations, Ultrasonics, Computer simulations, Wave propagation, 3D modeling

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Proceedings Article | 1 April 2011 Paper

Determination of the stress dependence of the velocity of Lamb waves in aluminum plates

U. Amjad, D. Jha, K. Tarar, H. Klinghammer, W. Grill

Proceedings Volume 7984, 798410 (2011) https://doi.org/10.1117/12.879902

KEYWORDS: Wave plates, Aluminum, Transducers, Wave propagation, Structural health monitoring, Ultrasonics, Lead, Waveguides, Electrodes, Fourier transforms

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Proceedings Article | 1 April 2011 Paper

Metamorphosis of bulk waves to Lamb waves in anisotropic piezoelectric crystals

A. Shelke, A. Habib, U. Amjad, M. Pluta, T. Kundu, U. Pietsch, W. Grill

Proceedings Volume 7984, 798415 (2011) https://doi.org/10.1117/12.880598

KEYWORDS: Crystals, Wave propagation, Acoustics, Dispersion, Wave plates, Visualization, Holography, Holograms, Ultrasonography, X-rays

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