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Laboratory investigation into the assessment of concrete pipes state of deterioration using ultrasonic testing techniques
Published in Mark Knight, Neil Thomson, Underground Infrastructure Research, 2020
M.C. López, M. Knight, G. Cascante
This research focuses on the use of ultrasonic NDT methods. Ultrasonic testing uses sonic waves of short wavelength and high frequency to detect flaws, fractures or measure material thickness. It is commonly used on aircrafts, at power generating plants, oil refineries, as well as paper mills. Ultrasonic testing measures the speed (wave velocity) and amplitude (attenuation) at which waves travel through the material. Changes in material properties can be attributed to changes in wave velocity and attenuation. Pulse Echo, Time of Flight of Diffraction, and Pulse Velocity are ultrasonic methods.
Analytical Methods
Published in Colin R. Gagg, Forensic Engineering, 2020
Ultrasonic testing: a non-destructive method in which beams of high-frequency sound waves are introduced into a material being evaluated to detect hidden cracks, voids, porosity and other internal discontinuities. High-frequency sound waves reflect from flaws in predictable ways, producing distinctive echo patterns that can be displayed and recorded by portable instruments. Ultrasonic flaw detectors are suitable for test house, laboratory and/or field use. They generate and display an ultrasonic waveform that is interpreted by a trained operator, often with the aid of analytical software, to locate and categorise flaws in failure detritus.
Aerospace production management
Published in Wesley Spreen, The Aerospace Business, 2019
Because consequences of material failure in aircraft are potentially catastrophic, and because aircraft structure is designed with minimal margins of extra strength, the industry has a vital interest in detecting invisible flaws in its products. It has been a leader in the development of numerous technologies to test the integrity of structure without causing physical damage to the part being inspected. Dye penetrant inspection is used to detect tiny surface cracks and structural flaws in non-porous materials. Test objects are coated with a fluorescent dye which is allowed to settle into any eventual cracks. The object is cleaned, leaving just the dye which has penetrated the cracks. The object is then exposed to a black light, causing residual dye in any cracks to glow, revealing their presence.Radiography in aerospace uses X-rays for thin materials and gamma rays for thicker materials to reveal interior structure. As digital imaging has replaced traditional film the process has become faster and less cumbersome. Recent advances include 3-D computed tomography (CT) scanning, which captures multiple X-rays of a test object from different angles to build up a cross-section view of the object on a computer.Ultrasonic testing uses high-frequency sound waves to locate defects within material by analyzing the reflection of the waves. It is commonly used to detect defects in welds, fittings, joints, bolts, and adhesive bonding.Eddy-current testing induces an electromagnetic field in a conductive test object and measures the secondary magnetic field generated around the electric current to locate flaws. Eddy-current testing is widely used in aircraft maintenance to detect cracks caused by fatigue or corrosion.Laser testing includes techniques such as shearography, holography, and profilometry, using laser light to detect deformation on the surface of objects. It is particularly effective in detecting tiny flaws undetectable to other measuring systems.
Ultrasonic characterisation of the elastic properties of mineral aggregates used in asphalt mixtures
Published in Road Materials and Pavement Design, 2023
Valentin Donev, Olaf Lahayne, Bernhard Pichler, Lukas Eberhardsteiner
Sound waves with frequencies larger than the human hearing range (>20 kHz) are called ultrasonic. Ultrasonic testing is a non-destructive test method with many engineering applications including flaw detection, dimensional measurements, quality control, and material characterisation. The method consists of sending ultrasonic waves through a material, which are then detected and analysed (see Krautkrämer & Krautkrämer, 1990). The very small stresses which are induced in the tested medium allow for assuming a linear relationship between stresses and strains. Moreover, the velocity of ultrasonic waves at a given temperature and pressure represents a characteristic material property.
Low sidelobe level and high time resolution for metallic ultrasonic testing with linear-chirp-Golay coded excitation
Published in Nondestructive Testing and Evaluation, 2018
Jiaying Zhang, Tie Gang, Chaofeng Ye, Sen Cong
Ultrasonic testing is widely used for non-destructive testing of metallic material, composites, concrete, etc. due to high reliability and accurate defect-sizing capabilities [1–3].In ultrasonic testing, time resolution and signal-to-noise rate need be improved to achieve more accurate measurement results [4–7]. However, there is a trade-off between wave penetration depth and time resolution in conventional brief pulse excitation ultrasonic testing that is lower frequency excitation coming along with greater penetrating depth but lower time resolution. On the other hand, higher frequency excitation has higher time resolution but less penetrating depth.
The study of micro-crack localisation based on vibro-acoustic modulation and time reversal method
Published in Nondestructive Testing and Evaluation, 2019
Zheng Huifeng, Hu Liuchen, Fang Piaopiao, Wang Yuebing, Cao Yonggang
Various non-destructive testing approaches are used for detecting the fatigue, corrosion and other early damages which will result in the deterioration of material properties in a long period of harsh environment. Ultrasonic testing approach is largely applied due to its wide range of detection, non-destructive testing and suitable for complex artefacts. Traditional linear ultrasonic is based on the linear characteristics such as reflection, scattering and attenuation of sound wave, but it only detects macroscopic defects [1–3].