High-frequency laser scanner with microscopic resolution for nondestructive evaluation of civil infrastructure

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This project is aimed at developing a new era in ultrasonic testing of civil infrastructure. The requested equipment will be used for the detection, from the surface of structure, of internal defects in civil infrastructure such as voids, corrosion, and general deterioration caused by aging. Ultrasonic transducers are commonly used in nondestructive testing (NDT) in civil and medical applications; where, changes in the medium conditions are inferred from changes in the travel time of a pulse between two points. These changes are evaluated from practically only one piece of information out of thousand of points that are actually recorded in a complete waveform. Why? Because ultrasonic transducers are not calibrated to measure the actual response of the medium in terms of displacement, velocity, or acceleration. Therefore, the real excitation and corresponding response of the medium are not known; only the time of travel (ultrasonic pulse velocity) is known. The new Laser system requested has the capabilities to measure the actual excitation and induced response generated by ultrasonic transducers. From the actual input and output measurements, the real properties of the medium can be measured. NDT methods are more economical and faster than destructive testing (e.g. coring, specimen and coupon testing). Therefore, to advance the use of ultrasonic transducers in nondestructive evaluation of civil infrastructure and even humans, a non-contact device capable of measuring high frequencies (f > 1 MHz) is needed. Previously, there was no such instrument available in the market. However, lasers vibrometers capable of measuring surface displacements in the nanometre and megahertz range are now available. To be competitive, the Canadian industry needs new and reliable techniques to perform cost-effective maintenance and rehabilitation operations for civil infrastructure. The high-frequency laser system requested is a state-of-the-art technology that will allow the research team to "see" the actual excitation and response displacements in ultrasonic testing; providing a quantum jump in the interpretation of ultrasonic NDT measurements.