Tomasz Lukomski

Stellantis · NA

The conventional synthetic aperture focusing technique (SAFT) can improve the lateral resolution and increase signal-to-noise ratio (SNR) in ultrasonic imaging. However, the use of SAFT in immersed inspection is limited due to the issues related to the refraction effects at the boundary between the water and a solid object. The virtual transducer (...

This paper proposes the non-stationary phase shift method for imaging layered objects and objects immersed in water with lateral velocity variations. The method presented allows inspection of both objects with complex geometry where the surface is not perpendicular to the axis of the transducer and layered objects where the layers are not horizonta...

Material properties such as strength, toughness or hardness are usually determined by destructive tests. However, continuous destructive measurements are generally difficult to perform during the production process, which creates a need for a fast and easy non-destructive method of material characterisation.Material elastic parameters, such as Youn...

In this work an alternative TOFD method is presented, capable to detect and size defects in the inspected material with good precision. It was shown that the diffraction used in this technique is the most relevant signal among the longitudinal backwall and the shear backwall echoes, compared to other TOFD methods. The proposed technique showed to b...

Imaging of solid layered objects using ultrasound presents normally a difficult task. Delay-and-sum (DAS) method, a standard and well-known method used for improving resolution in immersion setup, cannot properly reconstruct an image of layered objects. More advanced algorithms have been proposed for that purpose, like multi layered delay-and-sum (...

This paper introduces a method for an ultrasonic imaging with a phased array based on a wave migration algorithm. The method allows for imaging layered objects with lateral velocity variations such as objects with a complex geometry or layers that are not perpendicular to the array's axis. The full-matrix capture ensures that there is enough inform...

Resonant ultrasound spectroscopy (RUS) is a nondestructive technique originally developed for evaluating elastic constants of solids using resonance frequencies corresponding to the normal modes of vibration observed in samples with regular geometry. RUS can also be used for non-destructive evaluation of various metal or ceramic objects based on th...