Industrial Applications of Noncontact Ultrasonics Techniques

Battaglini, Luigi; Callegari, Sergio; Caporale, Salvatore; Davis, Lee A. J.; Laureti, Stefano; Senni, Luca; Hutchins, David A.

doi:10.1007/978-3-319-10566-6_11

Cited by 3 publications

(1 citation statement)

References 47 publications

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“…This is of importance in hazardous environments, especially when inspecting highly attenuating material [40]. In the case of PuC-ACUT it is particularly important—air attenuates ultrasonic signals, effectively constraining the technique to frequencies <1 MHz (at which attenuation of air is 120 dB·m −1 [67]).…”

Section: Pulse-compressionmentioning

confidence: 99%

Delamination Detection in Polymeric Ablative Materials Using Pulse-Compression Thermography and Air-Coupled Ultrasound

Laureti

Rizwan

Malekmohammadi

et al. 2019

Sensors

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Ablative materials are used extensively in the aerospace industry for protection against high thermal stresses and temperatures, an example being glass/silicone composites. The extreme conditions faced and the cost-risk related to the production/operating stage of such high-tech materials indicate the importance of detecting any anomaly or defect arising from the manufacturing process. In this paper, two different non-destructive testing techniques, namely active thermography and ultrasonic testing, have been used to detect a delamination in a glass/silicone composite. It is shown that a frequency modulated chirp signal and pulse-compression can successfully be used in active thermography for detecting such a delamination. Moreover, the same type of input signal and post-processing can be used to generate an image using air-coupled ultrasound, and an interesting comparison between the two can be made to further characterise the defect.

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Section: Pulse-compressionmentioning

confidence: 99%

Delamination Detection in Polymeric Ablative Materials Using Pulse-Compression Thermography and Air-Coupled Ultrasound

Laureti

Rizwan

Malekmohammadi

et al. 2019

Sensors

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Elasticity investigation of thin cellular structure films for piezoelectric sensors

Klimiec

Zachariasz

Kaczmarek

et al. 2021

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Purpose This paper aims to present the details of isotactic polypropylene (it-PP) films with a cellular structure (air-cavities) dedicated to pressure sensors. The polymer composites (thin films enriched with 5 and 10 wt% of mineral fillers as Sillikolloid P 87 and glass beads) should exhibit suitable structural elasticity within specific stress ranges. After the deformation force is removed, the sensor material must completely restore its original shape and size. Design/methodology/approach Estimating the stiffness tensor element (C33) for polymer films (nonpolar space-charge electrets) by broadband resonance ultrasound spectroscopy is a relatively simple method of determining the safe stress range generated in thin pressure sensors. Therefore, ultrasonic and piezoelectric studies were carried out on four composite it-PP films. First, the longitudinal velocity (vL) of ultrasonic waves passing through the it-PP film in the z-direction (thickness) was evaluated from the ω-position of mechanical resonance of the so-called insertion loss function. In turn, the d33 coefficient was calculated from accumulated piezoelectric charge density response to mechanical stress. Findings Research is at an early stage; however, it can be seen that the mechanical orientation of the it-PP film improves its piezoelectric properties. Moreover, the three-year electric charge stability of the it-PP film seems promising. Originality/value Ultrasonic spectroscopy can be successfully handled as a validation method in the small-lot production of polymer films with the air-cavities structure intended for pressure sensors. The structural repeatability of polymer films is strongly related to a homogeneous distribution of the electric charge on the electret surface.

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Thermographic Procedure for the Assessment of Resistance Projection Welds (Rpw): Investigating Parameters and Mechanical Performances

Dell'Avvocato,

Palumbo

2023

Preprint

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Industrial Applications of Noncontact Ultrasonics Techniques

Cited by 3 publications

References 47 publications

Delamination Detection in Polymeric Ablative Materials Using Pulse-Compression Thermography and Air-Coupled Ultrasound

Delamination Detection in Polymeric Ablative Materials Using Pulse-Compression Thermography and Air-Coupled Ultrasound

Elasticity investigation of thin cellular structure films for piezoelectric sensors

Thermographic Procedure for the Assessment of Resistance Projection Welds (Rpw): Investigating Parameters and Mechanical Performances

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