Award Abstract # 1914583
Collaborative Research: Conformal Gradient-Index Lenses for Ultrasonic Wave Amplification and Improved Diagnostics

NSF Org: CMMI
Division of Civil, Mechanical, and Manufacturing Innovation
Recipient: REGENTS OF THE UNIVERSITY OF MICHIGAN
Initial Amendment Date: June 18, 2019
Latest Amendment Date: June 18, 2019
Award Number: 1914583
Award Instrument: Standard Grant
Program Manager: Jordan Berg
jberg@nsf.gov
 (703)292-5365
CMMI
 Division of Civil, Mechanical, and Manufacturing Innovation
ENG
 Directorate for Engineering
Start Date: June 15, 2019
End Date: May 31, 2023 (Estimated)
Total Intended Award Amount: $368,517.00
Total Awarded Amount to Date: $368,517.00
Funds Obligated to Date: FY 2019 = $368,517.00
History of Investigator:
  • Serife Tol (Principal Investigator)
    stol@umich.edu
Recipient Sponsored Research Office: Regents of the University of Michigan - Ann Arbor
1109 GEDDES AVE STE 3300
ANN ARBOR
MI  US  48109-1015
(734)763-6438
Sponsor Congressional District: 06
Primary Place of Performance: University of Michigan
2350 Hayward Street
Ann Arbor
MI  US  48109-2125
Primary Place of Performance
Congressional District:
06
Unique Entity Identifier (UEI): GNJ7BBP73WE9
Parent UEI:
NSF Program(s): Dynamics, Control and System D
Primary Program Source: 01001920DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s): 034E, 8024, 9102
Program Element Code(s): 756900
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.041

ABSTRACT

Current structural systems are made of homogenous materials such as cast iron, wrought iron, bare steel, and brittle plastic, which are highly susceptible to failure and therefore require accelerated inspection and repair. Ultrasonics is a nondestructive evaluation method based on propagating elastic waves in structures, which are affected by defects in the structure and can therefore be used for damage diagnostics. However, in conventional structures, the amplitude of elastic waves decays with distance due to spreading/scattering, which limits the detectability of critical defects. In this research, new structural systems will be designed with an embedded or externally added lens so that ultrasonic signals can be focused and amplified as they propagate in the structure. In this way, ultrasonic wave energy can be transmitted and preserved over long distances. The research will allow detecting defects at their earliest stage and preventing unexpected failures. The target application will be pipeline systems due to their high susceptibility to failure. Therefore, results from this research will benefit the U.S. economy and society. This multi-disciplinary research encompasses metamaterials, sensors, additive manufacturing, structural monitoring, and design. The project features a synergistic educational component that integrates the strengths of two institutions in recruiting students who are underrepresented in engineering. In particular, female undergraduate and graduate students at both institutions will be connected via mutual workshops and the Society of Women Engineers (SWE).

This research will introduce a conformal gradient-index (GRIN) metamaterial lens as part of a structural system such that elastic waves will be amplified as they propagate through the non-planar structure. With the GRIN lens, different ultrasonic wave modes (i.e., longitudinal, flexural, or torsional) will be focused and transmitted such that higher frequencies (50-200 kHz) will be able to propagate with the increased sensitivity to structural damage. The GRIN lens will be designed by varying the refractive index of unit cells, and the existing model of the GRIN lens for flat surfaces will be modified for conformal surfaces. The metamaterial lens layer will be created with 3D printing, which will allow more practical and light weight structures to be easily integrated into the host structure. Additionally, a novel composite pipe structure, produced with multi-material additive manufacturing technologies, will be designed with the embedded metamaterial lens to address the highest risk of major incidents from the conventional materials used in pipelines.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

Note:  When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

Danawe, Hrishikesh and Li, Heqiu and Sun, Kai and Tol, Serife "Finite-Frequency Topological Maxwell Modes in Mechanical Self-Dual Kagome Lattices" Physical Review Letters , v.129 , 2022 https://doi.org/10.1103/PhysRevLett.129.204302 Citation Details
Danawe, Hrishikesh and Okudan, Gorkem and Ozevin, Didem and Tol, Serife "Conformal gradient-index phononic crystal lens for ultrasonic wave focusing in pipe-like structures" Applied Physics Letters , v.117 , 2020 https://doi.org/10.1063/5.0012316 Citation Details
Danawe, Hrishikesh and Tol, Serife "Broadband subwavelength imaging of flexural elastic waves in flat phononic crystal lenses" Scientific Reports , v.13 , 2023 https://doi.org/10.1038/s41598-023-34314-5 Citation Details
Danawe, Hrishikesh and Tol, Serife "Experimental realization of negative refraction and subwavelength imaging for flexural waves in phononic crystal plates" Journal of Sound and Vibration , v.518 , 2022 https://doi.org/10.1016/j.jsv.2021.116552 Citation Details
Danawe, Hrishikesh and Tol, Serife "Harnessing negative refraction and evanescent waves toward super-resolution Lamb wave imaging" Applied Physics Letters , v.123 , 2023 https://doi.org/10.1063/5.0152717 Citation Details
Okudan, Gorkem and Danawe, Hrishikesh and Ozevin, Didem and Tol, Serife "Torsional wave focusing in cylindrical structures with the conformal gradient-index phononic crystal lens" Journal of Applied Physics , v.129 , 2021 https://doi.org/10.1063/5.0050295 Citation Details
Okudan, Gorkem and Danawe, Hrishikesh and Zhang, Lu and Ozevin, Didem and Tol, Serife "Enhancing Acoustic Emission Characteristics in Pipe-Like Structures with Gradient-Index Phononic Crystal Lens" Materials , v.14 , 2021 https://doi.org/10.3390/ma14061552 Citation Details
Okudan, Gorkem and Xu, Chenxi and Danawe, Hrishikesh and Tol, Serife and Ozevin, Didem "Controlling the thickness dependence of torsional wave mode in pipe-like structures with the gradient-index phononic crystal lens" Ultrasonics , v.124 , 2022 https://doi.org/10.1016/j.ultras.2022.106728 Citation Details

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

"This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content."

In this collaborative project, we developed conformal gradient-index (GRIN) lenses as part of a structural system to amplify the wave as it propagates through the non-planar structure. Ultimately, the goal is to enhance structural diagnosis by transmitting and preserving wave energy over long distances, remedying the attenuation problem in nondestructive testing. To this end, we target the amplification of different wave modes (flexural, longitudinal, and torsional) that carry important structural information. The unit cells or lattices of the lens are tailored to achieve a special distribution of the refractive index in order to focus the ultrasonic wave energy at certain propagation distances. This is implemented in existing non-planar structures with a gradient-index metamaterial layer designed using varying-height solid cylinders that are externally attached to the structure. Additionally, we created a new composite metastructure by embedding metal beads with varying diameters in a polymer base structure. The graded height or diameter of inclusions causes the incident waves to be bent gradually toward the center axis where the refractive index is the highest (or the wave speed is the lowest), resulting in convergence at a focal spot. In addition to novel conformal lens concepts, we also developed a non-planar GRIN theory, which is based on ray trajectory calculations and results in better agreement with the experimentally measured and theoretically predicted focal spots. We test the theory on pipe-like and conical structures. Hence, these approaches can be further extended to other structural systems, including light poles and wind turbines. On the other hand, we also explored phononic crystal lenses based on negative refraction phenomena for subwavelength focusing. The ability of subwavelength focusing and potentially breaking diffraction limits will enable us to detect small defects. Hence, the outcomes of this project will impact other critical engineering applications, such as early detection in additively manufactured nuclear structures and components. In addition to technical outcomes, the educational impact of this research took multiple forms. The project supported several Ph.D. students and undergraduate students who delivered talks at conferences, published papers in high-impact journals, and effectively collaborated with other team members. The PI and PhD students gave guest lectures at UIC. The PI included research findings in the wave propagation course and included a guest lecture from UIC. Furthermore, PIs organized a mutual workshop to connect the female graduate students at both institutions, uniting the Society of Women Engineers (SWE).

 


Last Modified: 08/29/2023
Modified by: Serife Tol

Please report errors in award information by writing to: awardsearch@nsf.gov.

Print this page

Back to Top of page