Acoustic non-linearity for defect selective imaging

Krohn, N.; Stoessel, R.; Busse, G.

doi:10.1016/s0041-624x(02)00188-9

Cited by 70 publications

(48 citation statements)

References 3 publications

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“…Krohn et al [67] described the phenomena of generating higher harmonics caused by nonlinear damage. In brief, the tangential movement of a crack causes hysteretic energy dissipation, resulting in distortion of sinusoidal waves in a symmetrical manner.…”

Section: Nonlinear Acoustics Methodsmentioning

confidence: 99%

“…This clapping nonlinearity, resulting in a (sin ω)/ω decay, generates even harmonics. These types of nonlinearity are highly localized in the vicinity of the defects, so that the imaging methods utilizing a scanning laser vibro-meter can easily identify the location of damage [67]. As described in the previous section, the harmonic distortion methods have been widely used in structural damage identification, in particular, in the rotating machinery.…”

Section: Nonlinear Acoustics Methodsmentioning

confidence: 99%

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Nonlinear System Identification for Damage Detection

Farrar¹,

Worden²,

Todd³

et al. 2007

101

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Section: Nonlinear Acoustics Methodsmentioning

confidence: 99%

Section: Nonlinear Acoustics Methodsmentioning

confidence: 99%

Nonlinear System Identification for Damage Detection

Farrar¹,

Worden²,

Todd³

et al. 2007

101

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“…The presence of a defect changes the phase or amplitude of the 'interrogating' signal, while its frequency content remains unchanged. However, some types of defects, such as 'closed' defects or defects at the interface between materials with very dissimilar acoustic impedance (which might therefore mask any impedance mis-match arising from cracks or voids), may not be easily discerned by such linear techniques [15,16]. Various non-linear ultrasonic NDT approaches have therefore been developed to probe for the defects and damage in CFRP materials and other composites.…”

Section: Introductionmentioning

confidence: 99%

“…The most common include harmonic and overtone generation [15,16], inter-modulation product generation [17] and resonant frequency shift [18,19]. Of these approaches, that of harmonic generation is the longest established, having started in the 1970's and initially concentrating on second harmonic generation only [20].…”

Section: Introductionmentioning

confidence: 99%

“…The second harmonic generation technique has recently been combined with conventional C-scan imaging to provide a form of non-linear C-scan acoustic microscope for the imaging of fibre/matrix disbond and matrix cracking in CFRP plates [15]. Other researchers have used much higher order harmonics for the visualisation of defects in an attempt to improve the sensitivity of detection; for example Krohn et al used the 5th harmonic to visualise impact damage in CFRP samples, but also used the 2nd harmonic for the visualisation of heat induced damage [16]. Inter-modulation product generation is an alternative and potentially more sensitive non-linear method for defect detection in composites, and is based on the monitoring of non-linear wave mixing in the material.…”

Section: Introductionmentioning

confidence: 99%

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Design, development and testing of multi-functional non-linear ultrasonic instrumentation for the detection of defects and damage in CFRP materials and structures

Armitage

Wright

2013

Composites Science and Technology

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A multi-functional non-linear ultrasonic testing approach is presented for in-situ and ex-situ detection of a variety of defects (e.g. micro-cracking, delamination and disbonding) induced by various damage mechanisms (stress, impact, heat) in CFRP materials and structures. Such multi-functionality is provided via programmable and re-configurable instrumentation that incorporates a wide range of non-linear ultrasonic testing regimes, including harmonic and overtone generation, inter-modulation product generation, resonant frequency shift and pulse-inversion techniques. The capabilities of this multi-functional approach to defect detection are demonstrated by examining CFRP samples subjected to various forms of damage, specifically stress, impact and heat induced damage. We show that the multi-functional non-linear approach is well-suited to the detection of such forms of damage and that the pulse-inversion technique, largely 'ignored' in the CFRP literature, potentially provides a powerful, but as yet un-tapped, simple and effective route to the defect and damage detection. AbstractA multi-functional non-linear ultrasonic testing approach is presented for in-situ and exsitu detection of a variety of defects (e.g. micro-cracking, delamination and disbonding)induced by various damage mechanisms (stress, impact, heat) in CFRP materials and structures. Such multi-functionality is provided via programmable and re-configurable instrumentation that incorporates a wide range of non-linear ultrasonic testing regimes, including harmonic and overtone generation, inter-modulation product generation, resonant frequency shift and pulse-inversion techniques. The capabilities of this multifunctional approach to defect detection are demonstrated by examining CFRP samples subjected to various forms of damage, specifically stress, impact and heat induced damage. We show that the multi-functional non-linear approach is well-suited to the detection of such forms of damage and that the pulse-inversion technique, largely 'ignored' in the CFRP literature, potentially provides a powerful, but as yet un-tapped, simple and effective route to the defect and damage detection.

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Nondestructive Testing

Brunner¹,

Hack²,

Neuenschwander³

2004

Encyclopedia of Polymer Science and Technology

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Because of their unique properties, polymers and polymer–matrix composites pose both challenges and opportunities for nondestructive testing. The increasing use of these materials creates a demand for nondestructive verification of properties, structural integrity determination, or service‐life prediction. On the other hand, development of new nondestructive test methods, improved sensitivity, or faster data acquisition and analysis may allow for nondestructive testing applications that hitherto did not seem feasible or economical. This article provides a brief overview of established methods and emerging applications in nondestructive testing of polymers and polymer–matrix composites.

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Acoustic non-linearity for defect selective imaging

Cited by 70 publications

References 3 publications

Nonlinear System Identification for Damage Detection

Nonlinear System Identification for Damage Detection

Design, development and testing of multi-functional non-linear ultrasonic instrumentation for the detection of defects and damage in CFRP materials and structures

Nondestructive Testing

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