4387 - INVESTIGATION ON THE EFFECT OF IMPERFECT INTERFACE ON THE PROPERTIES OF LOVE WAVE PROPAGATION

Surface waves can be found many practical applications in MEMS and ultrasonic transducers. Love wavedevices/sensors are high sensitive devices which can be found much engineering significance in many signal transmission, signal processing and information storage applications. For the piezoelectricfilm/elastic substrate layered system, in practical applications, piezoelectricceramics often inherently have a much higher mechanical strength under compressive stresses in order to improve the reliability of transducers. On the other hand, due to the thermal mismatch, intrinsic stress and the brittleness nature of piezoelectricceramics, there exists unavoidable initial stress in above-mentioned piezoelectriclayered structures and imperfectionoccurs between the interfaces of the structures. These imperfectionsmay influence the propagation behavior of Love waves. Effects of imperfectionson the dispersion relations of Love wavein piezoelectriclayered structures are taken into account theoretically and experimentally. A new kind of contact-typeline-focused transducer is developed for the Love waveto be excited and detected. Experiments concerning the propagation of Love wavesin piezoelectriclayered structure are carried out to investigate the imperfectinterface effect. Results obtained in our research indicate that imperfectinterface can greatly influence the propagation properties of Love wavesunder some certain conditions. Experimental results agree well with the theoretical prediction, which also indicate that the novel Love wavetransducer developed by us is effective.