Focused Ultrasonic Beam Behavior at a Stress-Free Boundary and Applicability for Measuring Nonlinearity Parameter in a Reflection Mode

dc.contributor.author Jeong, Hyunjo
dc.contributor.author Zhang, Shuzeng
dc.contributor.author Kim, Jongboem
dc.contributor.author Li, Xiongbing
dc.date 2018-02-17T23:45:37.000
dc.date.accessioned 2020-06-30T06:54:54Z
dc.date.available 2020-06-30T06:54:54Z
dc.date.issued 2016-01-01
dc.description.abstract <p>Measurements of the acoustic nonlinearity parameter β are frequently made for early detection of damage in various materials. The practical implementation of the measurement technique has been limited to the through-transmission setup for determining the nonlinearity parameter of the second harmonic wave. For the purpose of practical applications, a pulse-echo measurement technique is more desirable which enables the single-side access of test components. The issue with using the second harmonic wave reflected from the stress-free interface is that such a boundary destructively alters the nonlinear generation process and consequently makes it difficult to obtain the reliable results of β.</p> <p>In this work, we employ a focused beam theory to modify the phase reversal at the stress-free boundary, and consequently enhance the second harmonic generation during its back-propagation toward the initial source position. We first confirm this concept through experiment by using a spherically focused beam at the water-air interface, and measuring the reflected second harmonic and comparing with a planar wave reflected from the same stress-free or a rigid boundary. In order to test the feasibility of this idea for measuring the nonlinearity parameter of solids in a reflection mode, an array transducer beam is modeled for focusing at and reflection from a stress-free boundary. A nonlinearity parameter expression is then defined together with diffraction and attenuation corrections.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/qnde/2016/abstracts/91/
dc.identifier.articleid 5062
dc.identifier.contextkey 9289418
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath qnde/2016/abstracts/91
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/62185
dc.language.iso en
dc.relation.ispartofseries Review of Progress in Quantitative Nondestructive Evaluation
dc.source.bitstream archive/lib.dr.iastate.edu/qnde/2016/abstracts/91/273_Focused_Ultrasonic.pdf|||Sat Jan 15 02:28:21 UTC 2022
dc.subject.disciplines Acoustics, Dynamics, and Controls
dc.subject.disciplines Mechanical Engineering
dc.subject.disciplines Mechanics of Materials
dc.title Focused Ultrasonic Beam Behavior at a Stress-Free Boundary and Applicability for Measuring Nonlinearity Parameter in a Reflection Mode
dc.type event
dc.type.genre event
dspace.entity.type Publication
relation.isSeriesOfPublication 289a28b5-887e-4ddb-8c51-a88d07ebc3f3
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