Surface-Adaptive Ultrasound (SAUL) for phased-array inspection of composite specimens with curved edges and complex geometry

Hopkins, Deborah; Brassard, Michael; Neau, Guillaume; Noiret, Jean-Noel; Johnson, W. V.; Ber, L. Le

doi:10.1063/1.4789128

Cited by 9 publications

(8 citation statements)

References 1 publication

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“…To meet future demand projections (for example in the aerospace sector) and overcome the bottlenecks of safety-critical NDT inspections, new automated scanning systems have been developed by a variety of research and development teams [10][11][12][13] . Producing reliable automated solutions has become an industry priority to drive down inspection times and ensure repeatability.…”

Section: The Need To Increase Speed and Improve Part Inspectabilitymentioning

confidence: 99%

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Correction of B-scan distortion for optimum ultrasonic imaging of backwalls with complex geometries

Davi¹,

Mineo²,

MacLeod³

et al. 2020

insight

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Ultrasound undergoes refraction and reflection at interfaces between media of different acoustic refractive indices. The most common ultrasonic method (pulse-echo) monitors the reflected energy to infer the presence of flaws, whereas the lower amplitude of refracted signals is ignored. When the reflector is orientated normally with respect to the ultrasonic beam, the received echo signal shows the maximum amplitude. The pulse-echo method also relies on monitoring the amplitude of the backwall echo to identify or confirm the presence of defects. This works well for parts with constant thickness and with planar backwalls. Unfortunately, parts with complex backwalls are common to many industrial sectors. For example, applications such as aerospace structures often require parts with complex shapes. Assessing such parts reliably is not trivial and can cause severe downtime in the aerospace manufacturing processes or during in-service inspections. This work aims to improve the ultrasonic inspectability of parts with complex backwalls, through sending ultrasonic beams from the frontwall side. Ultrasonic phased array probes and state-of-the-art instrumentation allow ultrasonic energy to be sent into a part at wide ranges of focusing depths and steering angles. This allows for tracking of the backwall profile, thus hitting it normally and maximising the amplitude of the reflected echo at any point. However, this work has shown that a cross-sectional scan resulting from multiple ultrasonic beams, which are sent at variable incidence angles, can present significant geometrical distortion and cannot be of much use for accurate defect visualisation and sizing. This paper introduces a generalised algorithm developed to remove geometric distortions and the effect that variable refraction coefficients have on the transmitted and received amplitudes. The algorithm was validated through CIVA simulations for two example parts with complex backwalls, considering isotropic materials.

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Section: The Need To Increase Speed and Improve Part Inspectabilitymentioning

confidence: 99%

“…Ultrasonic data can be collected and displayed in a number of different formats. Previous work has highlighted the importance of introducing new data visualisation and analysis tools capable of mapping complex geometries and enabling easy detection of defects [12,[28][29][30][31] .…”

Section: The Need To Increase Speed and Improve Part Inspectabilitymentioning

confidence: 99%

Correction of B-scan distortion for optimum ultrasonic imaging of backwalls with complex geometries

Davi¹,

Mineo²,

MacLeod³

et al. 2020

insight

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show abstract

“…Furthermore, different wedges are needed for different bend radius, and they are worn easily during the measurement. Although some water-immersed phased array techniques [4] can be applied for the inspection free of wedges, sophisticated delay laws are required to adapt to the complex surface geometry and to compensate for the probe misalignment, which is expensive and complicated for the long-range testing. Ultrasonic guided wave testing can be an effective alternative since it potentially allows for rapid screening of large areas with a fixed transducer position and remote inspection of structures with difficult access.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Damage detection in quasi-isotropic composite bends using ultrasonic feature guided waves

Ratassepp

Fan

2017

Composites Science and Technology

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“…Moreover, different wedges are needed for different bend curvatures, and they are worn easily during the measurement. Although some advanced water-immersed phased array techniques[152] were then applied for the inspection free of wedges, sophisticated delay laws are required to adapt to the complex surface geometry (i.e. Surface-Adaptive Ultrasound, SAUL) and to compensate for the probe misalignment[152,153], as5.…”

mentioning

confidence: 99%

“…Although some advanced water-immersed phased array techniques[152] were then applied for the inspection free of wedges, sophisticated delay laws are required to adapt to the complex surface geometry (i.e. Surface-Adaptive Ultrasound, SAUL) and to compensate for the probe misalignment[152,153], as5. Damage Detection in Multi-layered Quasi-isotropic Composite Bends Using Bend-guided Waves shown in Fig.…”

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confidence: 99%

Identification of damage in composite structures based on feature guided ultrasonic waves

Yu¹

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Complex-shaped composite laminates are increasingly utilized as Principal Structural Elements (PSE) such as spars, ribs, and the skin-stiffener combination in the aerospace industry. However, due to the stress concentration and out-of-plane impacts during the service life, various types of defects can be initiated in these structures, which have to be identified timely in case they propagate at subsurface laminae and ultimately lead to catastrophic failure. Therefore, this thesis explores the potential of exploiting a special type of ultrasonic guided wave, i.e. feature guided wave (FGW), for rapid screening of long-range composite structures. Such FGWs are capable of focusing their wave energy along the structural feature, with limited leakage into the adjacent plate. Two typical composite features are investigated in the thesis, which are laminated bends and adhesive composite joints, and the results are encouraging. Modal analysis of the laminated bend is carried out by using the Semi-Analytical Finite Element (SAFE) approach, in which the spatially-varying anisotropy is implemented to reveal the existing FGW modes. A shear horizontal type bend-guided (SH B) mode has been identified. The mode is almost non-dispersive and non-leaky, with strong energy confinement in the bend region, which is attractive to be applied as a screening tool for composite bends. Both 3D Finite Element (FE) simulations and experiments are performed to cross-validate the propagation characteristics of the SH B mode and to study its interaction with different defects occurred in the bend region, such as the interlaminar delamination and cracks, showing good agreement. The wave-defect resonance phenomenon and the reflection behaviour are investigated for localizing these two types of defects, and the capabilities of the SH B mode for efficient damage detection in long-range composite bends have been well demonstrated. Also, adhesive bonding is widely used in aerospace composites, and its integrity is crucial to the performance of the entire structure. This motivates the investigation of FGWs in another typical composite assembly, namely the stiffener-adhesive bond-'The poet, in dealing with the universe and with human life, must penetrate to their very core and at the same time must stand apart from them. By penetrating to their core he is thus able to describe them accurately; by standing apart from them he is able to observe them objectively. By penetrating to their core his works achieve life and vital force; by standing apart from them his works achieve loftiness.' Wang Kuo-wei, 1877~1927, Chinese scholar, writer and poet "诗人对宇宙人生，须入乎其内，又须出乎其外。入乎其内，故能写之。出乎其外，故能观之。入乎其内，故有生气。出乎其外，故有高致。" I would like to express my sincere gratitude to Professor Zheng (David) Fan for his excellent guidance and supervision throughout this work. It is invaluable experience to work with him, as his first Ph.D. student, to create everything from scratch. I have always been inspired by his scientific vision, educational philosophy, and passion for research, ...

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Surface-Adaptive Ultrasound (SAUL) for phased-array inspection of composite specimens with curved edges and complex geometry

Cited by 9 publications

References 1 publication

Correction of B-scan distortion for optimum ultrasonic imaging of backwalls with complex geometries

Correction of B-scan distortion for optimum ultrasonic imaging of backwalls with complex geometries

Damage detection in quasi-isotropic composite bends using ultrasonic feature guided waves

Identification of damage in composite structures based on feature guided ultrasonic waves

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