Nasrollahi, Amir
(2019)
On the Application of Highly Nonlinear Solitary Waves for Nondestructive Evaluation.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Highly nonlinear solitary waves (HNSWs) are compact nondispersive waves that can form and propagate in slightly compacted 1D chains of identical particles. Such a 1D chain is a heterogeneous lattice, which holds nonlinearity due to geometry and periodicity. Depending on the dynamic excitation, the particles support linear, weakly nonlinear, or highly nonlinear waves. The latter are triggered when the excitation generates a dynamic force much higher than the initial precompression.
Over the last decade, there has been a great effort to use HNSWs in engineering applications such as shock absorbers, energy harvesting, and nondestructive evaluation (NDE). For NDE application, many examples available in the literature show that the stiffness of the material/structure in contact with a chain of particles, where HNSWs are generated, affects the number, amplitude, and arrival time of the solitary waves.
In this dissertation, the dynamic interaction between HNSW and structure is investigated for three NDE applications: (1) determination of the elastic modulus and ultimate strength of concrete material, (2) measurement of the internal pressure and bouncing characteristics of tennis balls, and (3) estimation of axial stress in beams and continuous welded rails (CWRs). In the concrete application, the aim is to study the effect of water-to-cement ratio on the entire mix and on the surface of fresh concrete (simulating the undesirable water added to the fresh concrete by rain) on the solitary wave features. An experimental setup including seven solitary wave transducers and a numerical analysis simulating concrete samples as semi-infinite material is conducted to prove the feasibility and accuracy of the proposed HNSW method.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
|
| Date: |
24 January 2019 |
| Date Type: |
Publication |
| Defense Date: |
19 October 2018 |
| Approval Date: |
24 January 2019 |
| Submission Date: |
28 November 2018 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
215 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Civil and Environmental Engineering |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Highly Nonlinear Solitary Waves; Nondestructive Evaluation; Wave Propagation; Metamaterials |
| Date Deposited: |
24 Jan 2019 15:29 |
| Last Modified: |
24 Jan 2019 15:29 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/35650 |
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