Increased interest in non-contact ultrasound can be noticed. Signal energy and bandwidth become extremely important when high attenuation biological or industrial materials are inspected. Simple center frequency increase is not applicable due to attenuation and structural noise increase with frequency. Project aim is to enable and investigate the application of spread spectrum signals to non-contact ultrasound. Spread spectrum (SS) signals provide both bandwidth and SNR, offering new quality in measurements. However, transduction of the wideband signals in non-contact setup is more complicated than in contact or immersion setup. Three technologies have the potential to transduce the SS signals: i) Air-coupled ultrasound (ACU) ii) Electromagnetic acoustic transducers (EMAT) and iii) laser ultrasound (LUS). Yet, all these technologies have specific issues that prohibit their use with spread spectrum signals. Novel approach in ACU is to modify the piezoelement, enabling broadband transduction and matching. Also, investigation of new materials (e.g. ferroelectrets, FE) synergy with SS signals is planned. In LUS, we concentrate our research on thermoelastic regime using mid-power lasers. New electronics, optics and absorbing coating will be investigated in order to enable SS signals excitation normal to the surface. EMAT comparison to other two technologies is planned.
Project funding:
Projects funded by the Research Council of Lithuania (RCL), Projects carried out by researchers’ teams
Project results:
New measurement and imaging techniques, like resonance ultrasound spectroscopy, plate waves or local defect resonance will be enabled with broader bandwidth and higher SNR available thanks to the synergy of new transduction methods and SS excitation.
Patent applications at national and international offices are planned, 4 publications in Q1-Q2 WoS journals, 2 conference presentations.
Period of project implementation: 2023-07-01 - 2025-10-31
Project coordinator: Kaunas University of Technology
