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Phased-Arrays sensors and systems provide a great flexibility to UT inspectors, as the ultrasonic beam can be adjusted thanks to electronic set-up to increase performances (for detection or sizing) in different situations while using the same probe. For instance, the delay laws enable to steer the beam at different angles (sector scan technique) and/or focus the beam at different depths.

However, ultrasounds remain ultrasounds!

One key rule of acoustics is that you cannot focus beyond the near field distance (governed by the wavelength, frequency and crystal aperture)… And this remains absolutely true with phased-array sensors!

Rather than long explanations and mathematical formulas, let’s use CIVA simulations to illustrate this!

Above, you can see the sound field sector scan coverage generated in a carbon steel block by a linear PA UT probe of 2MHz and 26 mm aperture. The first beam chart on the top left illustrates a sector scan (30° to 60°) without any depth focusing, the max is around 50mm depth corresponding to the natural focal spot, which corresponds to the limit of the near field. Several focal laws are then successively applied to change the focal depth from 30 mm to 120 mm while keeping the same angular scanning. These focal laws lead to a geometrical focusing of the beam illustrated by the white cross, but as you can observe on the 3rd case, and above all the last case, the actual focus cannot be deeper compared to the geometrical “specification”.

It just takes a few minutes to illustrate this with CIVA, and can avoid many misunderstandings and misuse of PA UT probes and systems!

Feel free to contact us if you need more information about ultrasonic testing with CIVA.

The EXTENDE team.

When designing and qualifying Structural Health Monitoring (SHM) and predictive maintenance strategies, it is important to know for which defect size and location the system will be able to detect the damage. Experimentally, it is really difficult and costly to test lots of scenarios since this requires production of many mock-ups with different defects, and to implement all of them with embedded sensors.

CIVA SHM enables the simulation of Guided Waves monitoring, and includes imaging tools that can characterize a defect signature with a visible indication. It is very easy to define variable parameters with simulation. Thanks to metamodels available in CIVA software, modelling becomes even more powerful as you will be able to produce a continuum of results to fully explore the impact of different variable parameters.

Our video of CIVA SHM introduces one simulation example with a monitored aluminum plate. One defect is included, and the defect size and location are defined as variable parameters. Thanks to the CIVA metamodel, you can visualize all possible defect indications obtained in the range of variation defined, and then predict the situations where the system will be able to detect the flaw.

This CIVA example only required 4 hours of computation on a simple computer!

Feel free to contact us if you need more information about CIVA SHM and metamodels.

The EXTENDE team.