55 research outputs found
Sviluppo di nuove tecniche di caratterizzazione per sonde ad ultrasuoni in aria tramite la generazione di onde d'urto controllate
No full textQuantitative defect size estimation in shearography inspection by wavelet transform and shear correction
No full textUltrasonic Inspection of Thick Sandwich Composite Elements for Transport Infrastructures
No full textThe development of a shock-tube based characterization technique for air-coupled ultrasonic probes
No full textAdvanced ultrasonic non-destructive testing for damage detection on thick and curved composite elements for constructions
No full textSimilar and dissimilar FSWed joints in lightweight alloys: heating distribution assessment and IR thermography monitoring for on-line quality
No full textThe heating distribution assessment on similar and dissimilar friction stir welded joints in AA6082 and AA5754 aluminium alloy sheets was investigated. The FSW experiments were carried out using constant rotational and welding speeds of 1500 rpm and 60 mm/min, respectively. Temperature was locally measured by means of K-type thermocouples inserted into thin grooves located on the bottom side of the sheets, in fixed positions, very close to the welding line. It was observed that the mechanical properties of joints are related to the heat distribution. In order to obtain a completely non intrusive temperature monitoring, that was able to follow the process dynamic, a non-contact measurement system based on infrared thermography was also developed. Such system, used for the experimental evaluation of temperature on the upper surface of the joints, is also able to detect the presence of flow defects with a non-destructive method, demonstrating its effectiveness as a diagnostic instrument for the on-line quality control of welded joints
Improvement of defect size and morphological estimation in shearography inspection by wavelet transform
No full textQuantitative validation of an air-coupled ultrasonic probe model by Interferometric laser tomography
No full text
Characterization of porosity and defects on composite materials using X-ray computed tomography and image processing
No full textThis paper deals with the development of a measurement procedure to characterize anomalies, i.e. voids and defects, in four composite material (CM) samples. For this aim, four CM samples, each of them characterized by specific manufacturing techniques, have been analyzed. The first one (CM1) has Teflon defects, the second one (CM2) has undergone a low-degree manufacturing process and thus judged too porous at quality control, the third one (CM3) has passed the interlaminar shear strength (ILSS) test and so is expected to have a low-level of anomalies, unlike the fourth one (CM4), which has failed at ILSS test. An industrial X-ray computed tomography (CT) has been used to scan the CM samples and a specific image processing technique has been developed to measure the number and dimension of anomalies within them. The calculated amount of anomalies seems to be within the acceptable range identified in literature, always below 5%, showing the goodness of manufacturing process, and furthermore a threshold level of 0.09 mm has been statistically calculated to discriminate between voids and the other kinds of defects
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