Dr. Paul R. Ohodnicki Profile

Dr. Paul R. Ohodnicki

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Author

Publications (78)

Proceedings Article | 10 June 2024 Presentation + Paper

Numerical modeling of cylindrical non-axisymmetric elastic waves for damage detection using fiber optic sensors

E. Sarcinelli, P. Zhang, K. Naeem, R. Wright, N. Lalam, P. Ohodnicki

Proceedings Volume 13044, 130440M (2024) https://doi.org/10.1117/12.3013782

KEYWORDS: Waveguides, Sensors, Wave propagation, Data modeling, Fiber optics sensors, Pipes, Nondestructive evaluation, Elasticity, Actuators, Education and training

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Current ultrasonic acoustic NDE methods for long distance inspection in cylindrical structures are primarily focused on axisymmetric guided waves excitation. However, there are many occasions where the physical limitations imposed by the system to be inspected restrain the ability to utilize equipment capable of exciting those waves. This study explores the excitation of the flexural guided wave modes by a limited number of piezoelectric transducers for damage detection in hollow cylinders with limited surface access and large diameter. In addition, the use of distributed optical fiber system as the guided wave receptor is investigated as an alternative to piezoelectric transducers (PZT), as their capability to acquire spatial-temporal data synergizes with the complexity in a signal containing several flexural GW modes. More specifically, the study is conducted based on a numerical analysis of the guided waves excited by a 2 PZT configuration in a pipe available for experimental testing. The resulting flexural modes and its interaction with welds and local loss of material are analyzed in terms of the time series data of a local sensor in the surface, and the angular profile differences from a healthy case. A method based on the analytical solution of an infinite cylinder is introduced in preliminary stage to extract the behavior of the dominant modes from simulation and experimental results and used as a simulation-experiment similarity comparison. Finally, a simplified convolutional neural network (CNN) is trained to demonstrate feasibility of using flexural modes excited by limited actuators for damage detection. Overall, this study contributes to the development of a damage detection method applicable to cylindrical structures with dimensional and access limitations, by enhancing the understanding of how simultaneous several flexural modes interact with mechanical features, presenting an early-stage interpretable method to compare simulation and experimental fiber optic sensor data, and demonstrating the feasibility of using DAS like data for analyzing the structure.

Proceedings Article | 10 June 2024 Presentation + Paper

Investigation of data augmentation techniques for ultrasonic acoustic fiber sensing signals in guided wave-based pipeline damage detection

Pengdi Zhang, Khurram Naeem, Enrico Sarcinelli, Abhishek Venketeswaran, Sandeep Bukka, Nageswara Lalam, Ruishu Wright, Paul Ohodnicki

Proceedings Volume 13044, 130440J (2024) https://doi.org/10.1117/12.3013996

KEYWORDS: Data modeling, Waveguides, Fiber optics sensors, Sensors, Ultrasonics, Histograms, Acoustics, Pipes, Machine learning, Interference (communication)

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Proceedings Article | 7 June 2024 Presentation + Paper

Distributed optical fiber sensor systems: application to natural gas pipeline monitoring

Nageswara Lalam, Hari Bhatta, Michael Buric, Paul Ohodnicki, Ruishu Wright

Proceedings Volume 13044, 130440N (2024) https://doi.org/10.1117/12.3012866

KEYWORDS: Optical sensing, Fiber optics sensors, Vibration, Pipes, Acoustics, Single mode fibers, Safety, Rayleigh scattering, Photons, Optical fibers

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Proceedings Article | 7 June 2024 Presentation + Paper

Development of low-cost fiber optic temperature sensing interrogators for Li-ion battery thermal monitoring

Yang-Duan Su, Khurram Naeem, Atieh Shirzadeh, Heather Phillips, Paul Ohodnicki

Proceedings Volume 13044, 130440S (2024) https://doi.org/10.1117/12.3013275

KEYWORDS: Fiber Bragg gratings, Fiber optics sensors, Batteries, Fiber optics, Tunable filters, Optical sensing

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Proceedings Article | 7 June 2024 Presentation + Paper

Multimode interference-based fiber optic sensors using single mode/no-core/single mode (SNS) configuration

Tulika Khanikar, Dolendra Karki, Yang-Duan Su, Khurram Naeem, Paul Ohodnicki

Proceedings Volume 13044, 130440P (2024) https://doi.org/10.1117/12.3022011

KEYWORDS: Sensors, Fiber optics sensors, Single mode fibers, Multimode fibers, Fiber optics, Multimode interference devices, Refractive index, Spectral response, Signal intensity

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Proceedings Article | 7 June 2024 Presentation + Paper

Pipeline damage detection using multimode fiber-optic acoustic sensor and ultrasonic guided waves

Khurram Naeem, Pengdi Zhang, Enrico Sarcinelli, Dolendra Karki, Tulika Khanikar, Yang-Duan Su, Nageswara Lalam, Ruishu Wright, Paul Ohodnicki

Proceedings Volume 13044, 130440O (2024) https://doi.org/10.1117/12.3013838

KEYWORDS: Pipes, Acoustics, Sensors, Ultrasonics, Fiber optics sensors, Accelerometers, Vibration, Nondestructive evaluation, Multiplexing, Fiber optics

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Structural Health Monitoring (SHM) of pipelines using nondestructive testing/evaluation (NDT/E) techniques is important particularly for the energy industries and for the oil/gas distribution which helps reduction in maintenance costs as well as increased service lifespan. Among various NDE techniques, ultrasonic guidedwaves (GWs) technique is popular for inspection and monitoring of pipes due to its advantages e.g., long-distance monitoring using a fixed sensor probe, full volumetric coverage, and inspection for invisible or inaccessible structure. Recently, performance and scope of the GWs method is explored using optical fiber sensing technology such as fiber Bragg gratings are demonstrated for many ultrasonic sensing applications. The optical fiber sensors bring the advantage of remote sensing, large acoustic bandwidth, and multiplexing capability of the sensors to extend the range of GWs based NDE method. This work describes the health monitoring of damaged pipeline structure in a nondestructive manner using alternative No-core fiber (NCF) based quasi-distributed fiber-optic acoustic sensor combined with ultrasonic GWs excitation. We set up two similar 6-inch carbon-steel pipes (16-ft long), one consists of various defects and the other is healthy without any defect for reference. The pipes are actively excited by employing different ultrasonic sources; (1) magnetostrictive collar (MR) to generate the axisymmetric (torsion) GWs and (2) conventional piezoelectric patches to generate the antisymmetric flexural waves on the exterior surface, and the characteristics of acoustic-ultrasonic signals are studied using NCF based multiplexed fiber-optic sensor. Fiber optic sensor is an inline multimode interferometer made by sandwiching a piece of NCF (~5cm) between the single mode fibers. The NCF sensor is remotely bonded at 45° w.r.t pipe axis on one end and has an ultrasonic sensing range of >600kHz. Finally, the measured acousto-ultrasonic signals for different ultrasonic sources are compared to those obtained by the numerical simulation or electrical-based sensor for the healthy and damaged test pipes. The proposed work presents useful insight for damage detection in pipes using an NCF-based quasi-distributed fiber-optic acoustic sensor combined with ultrasonic GWs excitation.

Proceedings Article | 7 June 2024 Presentation + Paper

Dynamic response of magnetic fluid-cladded MMI fiber optic sensor optimized for fourth self-imaging spectral response

Dolendra Karki, Tulika Khanikar, Suraj Mullurkara, Khurram Naeem, Jun Young Hong, Paul Ohodnicki

Proceedings Volume 13044, 130440R (2024) https://doi.org/10.1117/12.3013823

KEYWORDS: Magnetometry, Nanoparticles, Multimode interference devices, Sensors, Frequency response, Magnetic sensors, Fiber optics sensors

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Proceedings Article | 7 June 2024 Presentation + Paper

Dopant segregation in single-crystal optical fiber grown via the laser-heated pedestal growth technique

Gary Lander, Jeffrey Wuenschell, Geunsik Lim, Dolendra Karki, Jun Young Hong, Paul Ohodnicki, Michael Buric

Proceedings Volume 13044, 130440H (2024) https://doi.org/10.1117/12.3013980

KEYWORDS: Dopants, Optical fibers, Structured optical fibers, Raman spectroscopy, Sapphire, Optical transmission, Neodymium

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Proceedings Article | 4 October 2023 Presentation + Paper

Plasmonic and interferometric optical fiber sensors for electrical system monitoring applications

P. Ohodnicki, Y. Su, D. Karki, T. Khanikar, K. Naeem, N. Lalam, J. Wuenschell, M. Buric, R. Wright

Proceedings Volume 12647, 126470H (2023) https://doi.org/10.1117/12.2677290

KEYWORDS: Sensors, Fiber optics sensors, Transformers, Acoustics, Magnetism, Chemical analysis, Acetylene, Magnetic sensors, Plasmonics, Vibration

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