Piezoelectric wafer active sensors (PWAS) are inexpensive, non-intrusive un-obtrusive devices that can be surface-mounted on existing structures, or inserted in a new composite structure. The PWAS can be used in both active and passive modes. In active mode, the PWAS generate Lamb waves that can exist as either traveling waves or standing waves. As traveling waves, PWAS-generated Lamb waves can...

Abstract For visualizing ultrasonic propagation, we have developed a generation laser scanning method. This method has the following features that make it superior to the conventional visualization methods such as the photo-elasticity method and the reception probe scanning method. (1) It enables us to visualize ultrasonic waves propagating on a complexly shaped object. (2) It makes high-speed ...

If it were possible to perform ultrasonic inspections while observing the propagation of ultrasonic waves as dynamic images, the identification of defect echoes would become easier, and inspection, quicker. Furthermore, fewer defects would be overlooked or improperly identified, leading to higher-reliability inspections. For visualizing ultrasonic propagation, we have developed a generation las...

Direct experimental evidence is given to show that the traditional viewpoint of polarization reversal must be modified to include the path of consecutive non-180◦ domain switching. Using ultrasonic waves, we have successfully monitored multi-domain formation during the polarization switching cycle in a bulk single crystal 0.955Pb(Zn1/3Nb2/3)O3-0.045PbTiO3. A model is proposed for the polarizati...