Design of a radiation plate for load testing of the torsional transducers

This paper presents a design method of a radiation plate with high load resistance for load testing of the torsional transducers. The calculation method for the torsional load impedance of the radiation plate seen from the transducer is proposed considering the flexural vibration mode excited in the radiation plate. The theoretical study using this calculation method indicates that the use of the `stripe' flexural vibration mode has advantage over the use of the `lattice' mode of controlling and obtaining a high load resistance. Furthermore, by using a combination of changing the node number of the stripe vibration mode and changing the thickness of the radiation plate, the design of the wide radiation plate which achieves a high load resistance without changing the resonant frequency is attempted. In an experimental study, the measured torsional load resistance of the prototype radiation plate agrees with the calculated one, and the torsional load resistance of 4.7 Nms was achieved with a 223 mm×50 mm radiation plate where the fifth stripe flexural vibration mode was excited. Load testing of the torsional transducer with the high torsional load was effectively conducted using the radiation plate designed by the proposed method.