Thermosonic Testing with Phase Matched Guided Wave Excitation

Rahammer, Markus; Solodov, Igor; Bisle, Wolfgang; Scherling, Dieter; Kreutzbruck, Marc

doi:10.1007/s10921-016-0363-7

Cited by 9 publications

(8 citation statements)

References 12 publications

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“…Traditionally, the core of all Sonic IR implementations have included an IR camera, and some method of introducing ultrasonic vibration. Low power methods have been suggested consisting of small lead zirconate titanate (PZT) elements [6], or directed wave energy methods [5] for exciting the displacement field. The most common method is to use an ultrasonic welding stack transduction system to introduce high power ultrasonic energy at a single location on the structure.…”

Section: Methodsmentioning

confidence: 99%

“…20 or 40 kHz). Recently, it has been demonstrated that each defect has a particular resonant frequency, referred to as the local defect resonance (LDR), at which its response will be maximized [5,6,7], and so stimulating a displacement field in the test piece that does not include the LDR will lead to a less than optimal thermal response. Thus, operating in a restricted range of frequencies has the effect of biasing the Sonic IR system towards a certain subset of defects whose LDRs are within the range of frequencies that are excited in the test piece.…”

Section: Introductionmentioning

confidence: 99%

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A novel thermosonic imaging system for non-destructive testing

Willey¹,

Xiang²,

Long³

2017

AIP Conference Proceedings

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Abstract. Thermosonic infrared (Sonic IR) imaging is a new non-destructive testing (NDT) technique that uses highfrequency sonic excitation together with infrared (IR) detection to image surface and subsurface defects. A conventional Sonic IR imaging system employs an ultrasonic welder, which is designed to operate at a single frequency. This single frequency ultrasonic source has been found to yield a "blind zone" for NDT due to the formation of standing waves inside the test piece. To overcome this limitation, a spring loaded ultrasonic transducer was used to generate the desired multifrequency acoustic chaos in the test object [1]. The limitation of the spring loaded ultrasonic transducer is its repeatability and reproducibility for field applications. In this work, we present the development of a novel thermosonic imaging system, which is capable of exciting the ultrasonic transducer at different frequencies for thermosonic NDT to overcome the limitations associated with a single frequency power source as well as the spring loaded transducer design. A comparison of experimental results will be made between the single frequency and the developed multi-frequency thermosonic NDT systems.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A novel thermosonic imaging system for non-destructive testing

Willey¹,

Xiang²,

Long³

2017

AIP Conference Proceedings

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“…Such a condition makes UST “non-reproducible”, thus leading to cracks being undetected if sufficient vibrational energy is not applied at the crack location. To overcome this issue, a new material elastic effect, known as local resonance defect (LDR), has recently gained considerable attention as it allows selective ultrasonic activation and higher sensitivity to the presence of structural flaws [ 118 , 119 , 120 ]. LDR shall be referred as the interaction of acoustic/ultrasonic waves with the damaged area at a frequency matching the defect resonance, which results in a substantial enhancement of the vibration amplitude only in the localised damaged region [ 121 ].…”

Section: Ultrasonic Stimulated Thermographymentioning

confidence: 99%

“…LDR also exhibits transitions from linear to nonlinear regime with the effect of generating higher and sub-harmonics of the input frequency [ 119 , 120 ]. Such an effect is typically known as “nonlinear LDR” [ 121 ], and the combination of thermosonics with this effect is known as “Nonlinear Ultrasonic Stimulated Thermography” (NUST).…”

Section: Ultrasonic Stimulated Thermographymentioning

confidence: 99%

Recent Advances in Active Infrared Thermography for Non-Destructive Testing of Aerospace Components

Ciampa

Mahmoodi

Pinto

et al. 2018

Sensors

366

185

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Active infrared thermography is a fast and accurate non-destructive evaluation technique that is of particular relevance to the aerospace industry for the inspection of aircraft and helicopters’ primary and secondary structures, aero-engine parts, spacecraft components and its subsystems. This review provides an exhaustive summary of most recent active thermographic methods used for aerospace applications according to their physical principle and thermal excitation sources. Besides traditional optically stimulated thermography, which uses external optical radiation such as flashes, heaters and laser systems, novel hybrid thermographic techniques are also investigated. These include ultrasonic stimulated thermography, which uses ultrasonic waves and the local damage resonance effect to enhance the reliability and sensitivity to micro-cracks, eddy current stimulated thermography, which uses cost-effective eddy current excitation to generate induction heating, and microwave thermography, which uses electromagnetic radiation at the microwave frequency bands to provide rapid detection of cracks and delamination. All these techniques are here analysed and numerous examples are provided for different damage scenarios and aerospace components in order to identify the strength and limitations of each thermographic technique. Moreover, alternative strategies to current external thermal excitation sources, here named as material-based thermography methods, are examined in this paper. These novel thermographic techniques rely on thermoresistive internal heating and offer a fast, low power, accurate and reliable assessment of damage in aerospace composites.

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“…The excitation at LDR frequencies allows for selective resonation of the defect's features by using low power piezoelectric actuators [9]. Generally, the component is excited at an LDR frequency of the defect and the corresponding vibration induced heat is diffused to the surface and detected using a high-sensitivity infrared camera [10][11][12][13][14][15]. The efficiency of LDR based vibrothermography can be enhanced through nonlinear ultrasound spectroscopy and selecting those LDR frequencies that indicate highest amplitudes of defect induced second harmonics [16][17][18].…”

Section: Accepted Manuscriptmentioning

confidence: 99%

In-plane local defect resonances for efficient vibrothermography of impacted carbon fiber-reinforced polymers (CFRP)

Segers

Hedayatrasa

Verboven

et al. 2019

NDT & E International

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It is well known that the efficiency of the vibrothermographic non-destructive testing (NDT) technique can be enhanced by taking advantage of local defect resonance (LDR) frequencies. Recently, the classical out-of-plane local defect resonance was extended towards in-plane LDR for enhanced efficiency of vibrometric NDT. This paper further couples the concept of this in-plane LDR to vibrothermography, on the basis of the promising potential of in-plane LDRs to enhance the rubbing (tangential) interaction and viscoelastic damping of defects. Carbon fiber-reinforced composites (CFRPs) with barely visible impact damage (BVID) are inspected and the significant contribution of in-plane LDRs in vibrational heating is demonstrated. Moreover, it is shown that the defect thermal contrast induced by in-plane LDRs is so high that it allows for easy detection of BVID by live monitoring of infrared thermal images during a single broadband sweep excitation. Thermal and vibrational spectra of the inspected surface are studied and the dominant contribution of in-plane LDR in vibration-induced heating is demonstrated.

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Thermosonic Testing with Phase Matched Guided Wave Excitation

Cited by 9 publications

References 12 publications

A novel thermosonic imaging system for non-destructive testing

A novel thermosonic imaging system for non-destructive testing

Recent Advances in Active Infrared Thermography for Non-Destructive Testing of Aerospace Components

In-plane local defect resonances for efficient vibrothermography of impacted carbon fiber-reinforced polymers (CFRP)

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