saeed zohoori - Research Assistant, University of Tehran, Center of/ldvanceci Systems and Technologies (CAST), North Kargar Ave.,۱۴۳۹۹-۵۶۱۹۱, Tehran, Iran.
aghil yousefi koma - Professor, University of Tehran, center of Advanced Systems and Technologies (CAST), North Kargar Ave.,۱۴۳۹۹-۵۶۱۹], Tehran, Iran.
mohammad hossein soorgee - Assistant Professor, F acuity of Mechanical and Energy Engineering, Shahid Beheshti University, Tehran, Iran

Using ultrasonic guided wave is one of the most reliable methods of condition monitoring and fault detection in different components. Mostly the bulk wave is preferred foridentification of internal defects, which is inefficient in localizing the surface cracks. In this paper the procedure of ultrasonic surface wave tomography for crack detection inan aluminum plate is investigated. Analytical equations and numerical simulations are used to extract dispersion curves as a means for selection of plate thickness and piezoelectric characteristics. Layout selection for transducers and providing numerical and experimental models are the next steps of inspection procedure. All the piezoelectric discs are actuated respectively. Meanwhile, other piezoelectric elements are used as sensors and their received signal is stored in both healthy and defected structures for both numerical and experimental models. Definition of signal dilfereriee criteria, signal reconstruction and totnogtam generation are the last steps of the procedure presented in this paper.

Tomography, Guided wave, Fault detection,Surface wave