Thesis of Hamza Chouh


Subject:
Interactive simulation of ultrasonic field for complex configuration of non-destructive control

Defense date: 22/11/2016

Advisor: Jean-Claude Iehl
Coadvisor: Jean-Philippe Farrugia

Summary:

In order to fulfill increasing reliability and safety requirements, non-destructive testing techniques are constantly evolving and so does their complexity.
Consequently, simulation is an essential part of their design.
We developed a tool for the simulation of the ultrasonic field radiated by any planar probes into non-destructive testing configurations involving meshed geometries without prominent edges, isotropic and anisotropic, homogeneous and heterogeneous materials, and wave trajectories that can include reflections and transmissions.
We approximate the ultrasonic wavefronts by using polynomial interpolators that are local to ultrasonic ray pencils. They are obtained using a surface research algorithm based on pencil tracing and successive subdivisions.
Their interpolators enable the computation of the necessary quantities for the impulse response computation on each point of a sampling of the transducer surface that fulfills the Shannon criterion.
By doing so, we can compute a global impulse response which, when convoluted with the excitation signal of the transducer, results in the ultrasonic field.
The usage of task parallelism and of SIMD instructions on the most computationally expensive steps yields an important performance boost.
Finally, we developed a tool for progressive visualization of field images. It benefits from an image reconstruction technique and schedules field computations in order to accelerate convergence towards the final image.