The present subject matter is direct to apparatus and methodologies for
performing omnidirectional (360.degree.) damage detection in a thin-wall
structure using a planar embedded piezoelectric wafer active sensors
(PWAS) phased array. Virtual beamforming for the array is implemented
through either a transmission process by selective energizing selected
sensors or by a signal post-processing procedure. Sensors may be embedded
in a thin-walled structure as planar or circular arrays to achieve
omnidirectional damage detection.