Laser-ultrasonics uses lasers to generate ultrasonic waves to detect objects and measure distances. A non-contact and non-destructive technique, it can be used on parts of a complex shape and/or at elevated temperatures. This technology is applicable to real industrial applications from the measurement of red hot steel tube thickness to inspection of aircraft parts made of composite materials. Unlike present measuring techniques that have often been cited as cumbersome to operate, this innovation is a more compact and simpler measurement system which is both accurate and cost effective because measurement takes place at the manufacturing site and results are recorded directly online.
This technology is available for licensing, or for further development through a collaborative research agreement with NRC. The business opportunity may be referred to by its NRC ID # 11166.
This innovation can be applied to almost any industry that requires manufacturing measurements and analysis of materials being created, from steel tubes to airplane parts to foil paper. Measures can be taken at various temperatures and of various composites.
This innovation can be used to develop effective concrete products for applications spanning electromagnetic shielding, anti-static flooring, corrosion protection of steel reinforcements, heating and radiant indoor heating.
How it works
A long pulse laser typically has a pulse duration in the range 1 μs to a few 100 μs. Long pulse lasers that provide the desired peak power with a pulse duration in the 100 μs range are known to be very noisy and are typically affected by strong relaxation oscillations and even spiking. If steps are taken to reduce intensity fluctuations if the proper demodulation is used, an effective solution to the problem is provided.
According to the present invention there is provided a method for ultrasonic testing of objects comprising the steps of generating ultrasound inside or at the surface of the object; illuminating the surface of the object with an incident beam from a long-pulse laser oscillator that is modified to be substantially free of intensity fluctuations; demodulating the scattered light with a frequency tracking demodulator to obtain a signal representative of the ultrasonic motion.
Suitable for small or large scale commercial production, this tool is simple and compact to run. It can be used without destroying or altering the item being manufactured and without disrupting the production line. Results are captured instantly online allowing for quicker turnover time of results.