6.12 Noncolinear wave mixing with phased array transducers

Inspection of drinking water supply means is of very great benefit to determine the remaining lifetime of a supply asset. With smart replacement strategies the use of raw materials and cost can be reduced, while enabling an even better water supply with high quality drinking water and very low downtime. Non-destructive ultrasonic testing is a common inspection means, however there is much to improve. PVC and other plastics are very hard to assess by current methods and a new technique has been developed in the Wetsus Smart Water Grids research theme which makes this possible. The technique is proven, however there is much to gain in terms of direct applicability.

The technique has been verified with standalone transducers, however extensive mechanical alignment and signal processing is necessary to obtain good measurements. The use of arrays eliminates the need for mechanical alignment, since this can now be done with (excitation) signal processing.

Research challenge
The challenge is to investigate the array techniques necessary to generate a well-defined ultrasonic intensity at a defined place in the material to be investigated, and secondly reading out the resulting signal. Also other techniques must be implemented, such as more commonly known pulse echo methods to determine parameters such as the distance to the sample and the angle of the sample. Lastly, the resulting signals from the sensors must be processed such that information about the material state is obtained.

We are looking for a candidate with an MSc degree in the field of electrical engineering, mechanical engineering or applied mathematics. Affinity with the ultrasonic field is a pre, experience with signal processing and experience with experimental set-ups and good communication skill, at least in English and preferably also in Dutch, is advantageous. You will be cooperating with more PhD students with similar interest in acoustics, data processing and electronics.

The project will be running in the Smart Water Grids theme within Wetsus where Vitens (, Brabant Water ( , PWN ( and Aquaint ( are company members. For this project there is collaboration with the University of Twente (UT).

Promotor: T. Tinga (University of Twente, Dynamics Based Maintenance group).
Supervisors: R. Loendersloot (Unversity of Twente) and Dr. Doekle Yntema (Wetsus).

For more contact please contact

Wetsus, Leeuwarden, The Netherlands


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