Measurement of Nonlinear Ultrasonic Characteristics

Preface
Contents
1 Overview—Nonlinear Ultrasonic Characteristics
	References
Measurements of Nonlinear Ultrasonic Characteristics Related with Material Elastic Nonlinearity
2 Measurement of Nonlinear Ultrasonic Parameters from Higher Harmonics
	2.1 Higher Harmonic Generation
	2.2 Nonlinear Ultrasonic Parameters
	2.3 Measurement of Nonlinear Ultrasonic Parameters
		2.3.1 Absolute Nonlinear Ultrasonic Parameter (Piezoelectric Method)
		2.3.2 Relative Nonlinear Ultrasonic Parameter
		2.3.3 Estimation of Absolute Nonlinear Ultrasonic Parameter by Measurement of Relative Nonlinear Ultrasonic Parameters
		2.3.4 Measurement Reliability Test
	2.4 Factors Affecting Measurement Reliability
		2.4.1 Uncertain Initial Harmonics
		2.4.2 Couplant Layer
		2.4.3 Analog-to-Digital Conversion
		2.4.4 Digital Signal Processing
	2.5 Application to Assess Thermal Aging in Al Alloy
	2.6 Associated Methodologies
		2.6.1 Phase Inversion Technique
		2.6.2 Pulse-Echo
		2.6.3 V-Scan
		2.6.4 Laser-Ultrasonic Surface Acoustic Waves
	References
3 Measurement of Nonlinear Guided Waves
	3.1 Introduction
	3.2 Background
		3.2.1 Linear Guided Wave Propagation
		3.2.2 Brief History of Nonlinear Guided Waves
	3.3 Primary Wave Selection for Secondary Wave Generation
		3.3.1 Basic Principles
		3.3.2 Theoretical Formulation
		3.3.3 Self-interaction
		3.3.4 Mutual Interaction in Plate
	3.4 Actuation of Primary Waves and Sensing of Secondary Waves
		3.4.1 Actuation of Lamb Waves
		3.4.2 Actuation of SH Waves
		3.4.3 Sensing
		3.4.4 Effects of Diffraction
	3.5 Instrumentation and Signal Processing
		3.5.1 Instrumentation
		3.5.2 Signal Processing
	3.6 Measurement Considerations
		3.6.1 Measurement System Nonlinearities
		3.6.2 Material Nonlinearities
		3.6.3 Measuring Progressive Degradation
	3.7 Closing Comments
	References
Measurements of Nonlinear Ultrasonic Characteristics Related with Contact Acoustic Nonlinearity
4 Nonlinear Acoustic Measurements for NDE Applications: Waves Versus Vibrations
	4.1 Introduction
	4.2 Fundamental Effect in Nonlinear Acoustics: Higher Harmonic Generation for Longitudinal Acoustic Waves
		4.2.1 Experimental Validation of Higher Harmonic Characteristics
	4.3 Nonlinear SAW: Theory
		4.3.1 Nonlinear Surface Waves: Experimental
	4.4 Localized Nonlinearity of a Non-bonded Interface
	4.5 Localized Nonlinearity for Monitoring of Bonding Quality
		4.5.1 Methodology
		4.5.2 Specimens
		4.5.3 Measurement Results
		4.5.4 Evaluation of Bonding Quality in Realistic Aviation Components
	4.6 Local Defect Resonance (LDR) and Localized Nonlinearity
	4.7 Enhancement of Nonlinearity in Various Types of Nonlinear Resonances
		4.7.1 Super-Harmonic Resonance
		4.7.2 Combination Frequency Resonance
		4.7.3 Subharmonic and Parametric Resonances
	4.8 Linear and Nonlinear LDR for Non-contact Diagnostic Imaging of Defects
		4.8.1 Experimental Methodology
		4.8.2 Noncontact LDR Imaging Results
		4.8.3 Nonlinear LDR Diagnostic Imaging
	4.9 Conclusions
	References
5 Nonlinear Ultrasonic Phased Array for Measurement of Closed-Crack Depth
	5.1 Introduction
	5.2 Subharmonics
		5.2.1 Principles
		5.2.2 Experimental Conditions
		5.2.3 Imaging Results
	5.3 Parallel and Sequential Transmission
		5.3.1 Principles
		5.3.2 Experimental Conditions
		5.3.3 Imaging Results
	5.4 All-Elements, Odd-Elements, and Even-Elements Transmission
		5.4.1 Principles
		5.4.2 Experimental Conditions
		5.4.3 Imaging Results
	5.5 Utilization of Thermal Stress
		5.5.1 Principles
		5.5.2 Experimental Conditions
		5.5.3 Imaging Results
	5.6 Conclusions
	References
6 Nonlinear Frequency-Mixing Photoacoustic Characterisation  of a Crack
	6.1 Introduction to Nonlinear Photoacoustics
		6.1.1 An Overview of a Few Non-destructive Methods Combining Laser Optics with Nonlinear Acoustics
		6.1.2 Generation of Thermoelastic Stresses and Acoustic Waves by Modulation of Continuous Wave Laser Radiation
		6.1.3 Influence of Stationary Laser Heating on a Crack
	6.2 Nonlinear Frequency-Mixing Photoacoustic Method for Crack Detection
		6.2.1 Experimental Setup
		6.2.2 Principle of the Method
		6.2.3 One Dimensional Imaging for Crack Localisation
		6.2.4 Two Dimensional Imaging of a Crack
		6.2.5 Spatial Resolution of the Crack Images
	6.3 Towards Quantitative Evaluation of Local Crack Parameters
		6.3.1 Theoretical Model
		6.3.2 Evolution of the Nonlinear Sidelobes Amplitude with the Loading
		6.3.3 Extraction of Crack Parameters
	6.4 Conclusion
	References
Index