Locally Structured Fiber Reinforcements: An Approach to Realize Anisotropic Directivity Pattern in Ultrasound Transducers

Ultrasonic transducers are widely used in automotive and industrial applications for surround sensing. Anisotropic directivity patterns with a narrow-angled beam in the vertical plane and a wide-angled beam in the horizontal plane are needed in automotive applications particularly. Today’s ultrasonic transducers for automotive applications are mainly metal based, pot-like ultrasonic transducers. The anisotropic directivity pattern is achieved by increasing the thickness of the vibrating plate-like part of the structure locally. Composites with locally structured fiber reinforcements open up the possibility to design the dynamical behavior of components without changing its contour. Using this new dimension of design to modify the directivity pattern of sound radiating components is less examined in literature. In this work, the possibility of creating an anisotropic directivity pattern by locally structuring the fiber reinforcement is investigated using a generic ultrasonic transducer model. The structuring is realized by sections of carbon fiber reinforced epoxy and sections made of epoxy only. Furthermore, the influence of geometrical and material uncertainties of the fiber reinforcement on the directivity pattern is discussed. The authors identify locally structured fiber reinforcements as a suitable possibility to create an anisotropic directivity pattern of an ultrasonic transducer.