Conventional ultrasonic methods based on ultrasonic characteristics in the linear elastic region are mainly sensitive to mature defects but are much less responsive to micro-damage or incipient material degradation. Recently, nonlinear ultrasonic characteristics beyond the linear ultrasonic amplitude range have been studied as a method for overcoming this limitation, and hence, many researchers are engaged in theoretical, experimental, and various application studies. However, the nonlinear ultrasonic characteristics are quite exacting compared to the linear phenomena so that they require vast experience and high proficiency in order to obtain proper experimental data. Actually, many researchers, especially beginners including graduate students, have difficulty in reliably measuring nonlinear ultrasonic characteristics. This book provides key technological know-how from experts with years of experience in this field, which will help researchers and engineers to obtain a clear understanding and high quality data in the nonlinear ultrasonic experiments and applications.
Preface.
Chapter 1. Overviews: Nonlinear Ultrasonic Characteristics and
Measurands.
Chapter 2. Elastic Nonlinearity induced Nonlinear Ultrasonic
Characteristics.- 2.1 Higher Harmonics (HH) Generation,-2.2 Nonlinear
Ultrasonic Parameters.- 2.2.1 Absolute Nonlinear Ultrasonic Parameter.- 2.2.2
Relative Nonlinear Ultrasonic Parameter.- 2.3 Measurement of Nonlinear
Ultrasonic Parameter.- 2.3.1 Capacitive Detection and Laser-interferometric
Detection.- 2.3.2 Piezo-electric Detection.- 2.3.3 Control of Propagation
Distance and Control of Incident Wave Power.- 2.3.4 Phase Inversion
Technique.- 2.4 Factors Affecting to Measurement Reliability.- 2.4.1
Measurement System: Transducer, Input Power, Contact Pressure, Electronic
Equipment.- 2.4.2 Digital Signal Processings: Bandwidth of Incident Wave,
Time Resolution, Amplitude Resolution.- 2.5 Applications to Assessment of
Material Damage.- 2.5.1 Fatigue Damage.- 2.5.2 Plastic Deformation.- 2.5.3
Thermal Aging.- References.
Chapter 3. Nonlinear Acoustic Wave Interactions
with Contact Interfaces: Methodologies and Applications.- 3.1. Nonlinear
Reflection Approach to Interface Nonlinearity.- 3.1.1 Nonlinear acoustic
reflection at an ideally bonded interface.- 3.2.1 Application of Reflection
Concept to Nonlinear Interface Wave Propagation.- 3.3.1 Second Harmonic
Generation of Interface Acoustic Waves.- 3.2. Acoustic Nonlinearity of a
Non-Bonded Interface.- 3.2.1 Phenomenology of Contact Acoustic Nonlinearity
(CAN).- 3.2.2 Higher Harmonics (HH) Generation at Contact Interfaces.-
3.2.3 Nonlinear Acoustic Reflection by Fractured Defects.- 3.2.4 Acoustic
Rectification and Nonlinear Polarization Effects via CAN.- 3.3. Non-Classical
Nonlinear Effects in Resonant Contact Inclusions.- 3.3.1 Concept of Local
Defect Resonance.- 3.3.2 Sub- and Super-harmonic Resonances.- 3.3.3
Nonlinear Parametric Instability Effects.- 3.4. Applications for
NonlinearImaging of Defects.- 3.4.1 Nonlinear Scanning Laser Vibrometry.-
3.4.2 Nonlinear Air-Coupled Emission (NACE).- 3.4.3 Case Studies of
Nonlinear Imaging of Defects.- References.
Chapter 4.
Nonlinear Ultrasonic Phased Array for Measurement of Closed-Crack Depth.-
4.1. Introduction.- 4.2. Harmonics.- 4.2.1. Principles.- 4.2.2. Experimental
conditions.- 4.2.3. Imaging results.- 4.3. Parallel and sequential
transmission.- 4.3.1. Principles.- 4.3.2. Experimental conditions.- 4.3.3.
Imaging results.- 4.4. Full-, odd- and even-elements transmission.- 4.4.1.
Principles.- 4.4.2. Experimental conditions.- 4.4.3. Imaging results.- 4.5.
Utilization of thermal stress.- 4.5.1. Principles.- 4.5.2. Experimental
conditions.- 4.5.3. Imaging results.- References.
Chapter 5. Nonlinear
Guided Waves.- 5.1. Introduction.- 5.2. Background on guided wave
propagation.- 5.3. Self Interaction.- 5.3.1. Basic principles.- 5.3.2. Lamb
waves in plate.- 5.3.3. Shear horizontal waves in plate.- 5.3.4. Axisymmetric
waves in pipe.- 5.3.5. Flexural waves in pipe.- 5.4. Mutual interaction in
plate.- 5.4.1. Basic principles.- 5.4.2. Collinear waves.- 5.4.3.
Non-collinear waves.- 5.5. Actuation of primary waves and reception of
secondary waves.- 5.5.1. Actuation of Lamb and L(0,n) waves.- 5.5.2.
Actuation of SH and T(0,n) waves.- 5.5.3. Reception.- 5.5.4. Effects of
diffraction .- 5.6. Signal processing.- 5.6.1. Fast Fourier transform.-
5.6.2. Phase inversion.- 5.7. Measurement considerations.- 5.7.1. Measurement
nonlinearities.- 5.7.2. Material nonlinearity.- 5.7.3. Contact acoustic
nonlinearity.- 5.7.4. Measuring progressive degradation.- References.-
Chapter 6. Nonlinear Frequency-Mixing Photoacoustic Characterization
of a Crack .- 6.1. Introduction in nonlinear photoacoustics.- 6.1.1. An
overview of NDT methods combining laser optics with nonlinear acoustics.-
6.1.2.Generation of the thermo-elastic stresses and of acoustic waves by
modulation of cw-laser radiation.- 6.1.3. Influence of stationary laser
heating on a crack.- 6.2. Nonlinear frequency-mixing photo-acoustic method
for crack detection.- 6.2.1. Principle of the method.- 6.2.2. One dimensional
imaging of a crack.- 6.2.3. Two-dimensional imaging of a crack.- 6.2.4. Role
of classical and nonclassical nonlinearities.- 6.3. Breathing and spatial
resolution evolution with experimental parameters.- 6.3.1. Influence of the
probe power.- 6.3.2. Influence of the pump power.- 6.3.3. Influence of the
local crack parameters.- 6.4. Towards quantitative evaluation of local crack
parameters.- 6.4.1. Experimental observations.- 6.4.2. Theoretical
model,-6.4.3. Extraction of crack parameters,-References
Kyung-Young Jhang received his PhD from Tokyo Institute of Technology, Japan in 1991. He is currently a Professor and the Chair of Mechanical Engineering at Hanyang University. His research focuses on the area of linear & nonlinear ultrasonics for NDT&E, laser ultrasonics and laser-material intraction, ultrasonic and optical measurements and signal & image processing. He was Vice-president of Korean Society for NDT and Editor-in-Chief of Journal of the Korean Society for NDT (2012-2017).
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