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Beamforming in Plates Using Embedded Acoustic Metamaterial Lenses



In this paper we present a novel technique to design a single ultrasonic transducer system for selective damage interrogation. The design is based on the concept of acoustic metamaterials. The structural area around the transducer is dynamically tailored by using a periodic distribution of resonant inclusions acting as an acoustic lens. The inclusions are arranged in order to form a circular anisotropic lens having an ultrasonic transducer located at its centre. The properties of the lens can be locally tailored in the azimuthal direction allowing controlling the direction of excitation by simply tuning the frequencies of excitation. Numerical results show that the proposed lens design is able to create highly directional and collimated ultrasonic beams by using a single transducer, therefore, overcoming some of the major limitations due to phased array technology.

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