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Nonlinear Assessment of Material and Interface Imperfections Based on Non-Collinear Shear Wave Mixing

Zhang, Ziyin
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458814847

Abstract Details

2016, MS, University of Cincinnati, Engineering and Applied Science: Aerospace Engineering.
Non-collinear shear wave mixing has been reported to exhibit potential for assessing the additional nonlinearity caused by both bulk material degradation and interface imperfections between solids. When this technique is used to assess the material bulk nonlinearity, certain resonance condition has to be satisfied while when it is used to assess the nonlinearity of an imperfect plane interface between two half-solids, the resonance condition can be relaxed. However, even when misaligned from the bulk resonance conditions, this technique is still somewhat sensitive to the intrinsic bulk nonlinearity and the relatively strong bulk nonlinearity of the surrounding material adversely reduces the nonlinear contrast produced by interface imperfections. In an effort to increase the nonlinear contrast produced by the imperfect interfaces, this research focused on conducting a combined analytical and computational investigation to identify the optimal inspection conditions for ultrasonic characterization of imperfect interfaces based on non-collinear shear wave mixing. The mechanism of nonlinear shear wave mixing technique was further investigated to identify the main factors which affect the strength of the detected bulk nonlinearity of the material. Then two analytical models for nonlinear imperfect interfaces were developed by using a finite nonlinear interfacial stiffness representation of an imperfect interface of vanishing thickness and a thin nonlinear interphase layer in a quasi-static approximation, respectively. Both analytical models were numerically verified by comparison to COMSOL finite element simulations. The results show that the imperfect interface generates the same amount of nonlinearity in both reflection and transmission fields and detecting the nonlinear reflection completely eliminates the adverse influence of bulk nonlinearity and therefore increases the nonlinear contrast generated by the imperfect interface. The feasibility of detecting the nonlinear reflection from the imperfect interface has also been confirmed to be possible by the experiment on Ti-6Al-4V diffusion bonded specimens using enhanced non-collinear ultrasonic wave mixing system implemented with a novel four-way polarity flipping technique.
Peter Nagy, Ph.D. (Committee Chair)
Waled T. Hassan, Ph.D. (Committee Member)
Francesco Simonetti, Ph.D. (Committee Member)
118 p.
Acoustics

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Citations

  • Zhang, Z. (2016). Nonlinear Assessment of Material and Interface Imperfections Based on Non-Collinear Shear Wave Mixing [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458814847

    APA Style (7th edition)

  • Zhang, Ziyin. Nonlinear Assessment of Material and Interface Imperfections Based on Non-Collinear Shear Wave Mixing. 2016. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458814847.

    MLA Style (8th edition)

  • Zhang, Ziyin. "Nonlinear Assessment of Material and Interface Imperfections Based on Non-Collinear Shear Wave Mixing." Master's thesis, University of Cincinnati, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458814847

    Chicago Manual of Style (17th edition)

ucin1458814847
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© 2016, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.