3D-analysis of bending-type transducers for distance measurement applications

Ultrasonic sensors are commonly utilized for a wide variety of non-contact presence, proximity or distance measuring applications in industry, especially the automotive branch. This paper shows how the radiation properties of bending-type ultrasonic transducers depend on shape, dimensions and material parameters. In order to determine their dependencies, the behavior of such transducers with regard to their emitting characteristics in air is simulated using the finite element (FE) method. Therewith, the electrical impedance as well as the surface elongation together with the radiated ultrasound is computed. For performing reliable simulations, we utilize a mathematical inverse method (IM) to identify the material parameters. The results of the FE simulations have been validated by laser doppler velocimetry (LDV) and acoustic pressure measurements.