  In this study, we present an approach to ultrasonic beamforming and high
resolution identification of acoustic sources having critical implications for
structural health monitoring technology. The proposed concept is based on the
design of dynamically tailored structural elements via embedded acoustic
metamaterial lenses. This approach provides a completely new alternative to
conventional phased-array technology enabling the formation of steerable and
collimated (or focused) ultrasonic beams by exploiting a single transducer. The
ultrasonic beams can be steered by simply tuning the frequency of the
excitation. Also, the embedded lens can be designed to achieve sub-wavelength
resolution to incipient clustered damage.
