This paper presents a piezoelectric-metal structure called a drum transducer. An equation for calculating the resonance frequency of the drum transducer is obtained based on thin plate elastic theory of piezoelectric and metal material combined with the Rayleigh-Ritz method. The finite element method (FEM) was used to predict the excitation frequency of the drum transducer. To verify the theoretical analysis, the input impedance characteristic of the drum transducer was measured using an experimental method. The results obtained from theoretical analysis were in very good agreement with those from the FEM and experimental results. The effect of geometrical changes to the thick-walled steel ring of the drum transducer at the first resonance frequency is also described. The calculated results were found to be in good agreement with the FEM results. The results indicate that the first resonance frequency of the drum decreases with the increasing inner diameter of the thick-walled steel ring.
A cymbal transducer is made up of a piezoceramic disk sandwiched between two dome-shaped metal endcaps.High circumferential stresses caused by flexural motion of the metal endcaps can induce the loss of mechanical input energy.Finite element analysis shows that the radial slots fabricated in metal endcaps can release the circumferential stresses,and reduce the loss of mechanical input energy that could be converted into electrical energy.In this letter,the performance of a slotted-cymbal transducer in energy harvesting was tested.The results show that the output voltage and power of the cymbal are improved.A maximum output power of around 16 mW could be harvested from a cymbal with 18 cone radial slots across a 500 kΩ resistive load,which is approximately 0.6 times more than that of the original cymbal transducer.
