A Comparative Study of Divergent Surface Acoustic Wave Beams' Generation on an Y128° Lithium Niobate Using Various Types of Interdigital Transducers.

This study focuses on the possibility of generating divergent surface acoustic waves (SAWs) with interdigital transducers (IDTs) deposited on Y128° Lithium Niobate for non-destructive testing applications, particularly in the context of manufacturing layer-on-substrate systems for microelectronic components. The selected approach is to diffuse the SAWs over a large surface area and in various directions in order to analyze the structure and detect any defects when using the well-known passive imaging by correlating the diffuse acoustic field. The introduction of SAWs is achieved using offset interdigital transducers that make acoustic contact with the sample under analysis without causing damage.

Quantification and mitigation of the effect of resynchronization errors in ultrasound sensor network for passive imaging in elastic plates.

The problem of signal desynchronization in passive imaging based on noise correlation for defect detection in elastic plates is investigated. Although a post-processing resynchronization process relying on the symmetry of noise correlation functions can be applied prior to the imaging algorithm, perfect synchronization might not be achieved experimentally. Effect of such residual synchronization errors on the defect detection performance is quantified as a function of their probability density function.

Monitoring saltwater corrosion of steel using ultrasonic coda wave interferometry with temperature control.

Assessing corrosion is crucial in the petrochemical and marine industries. Usual ultrasonic methods based on pulse-echo and guided waves to detect corrosion lack of precision and struggle in structures with a complex shape. In this paper, a complementary and sensitive ultrasonic method based on coda wave interferometry is presented to detect and quantify thickness loss caused by saltwater corrosion of a steel sample.

Pump-probe localization technique of varying solid contacts.

A baseline-free defect localization method in thin plates is proposed and tested. In this proof-of-concept work, a steel ball pressed against an aluminum plate is used to mimic a surface contact defect. The technique takes benefit of a repetitive nonlinear pump-probe interaction with a backpropagation imaging algorithm.

A micro-transducer matrix design for the detection of flexural guided waves.

In this paper, a new approach is proposed for the detection of ultrasonic guided waves using a LiNbO single crystal-based micro-transducer matrix. This matrix was designed, manufactured, and then used to detect Lamb and Pochhammer-Chree guided waves in plate- and cylinder-like structures. This study highlights the identification of the first flexural mode F(1,1) in cylinders at low frequencies.