Abstract:
Piezoelectric transducers have gained significant importance over the past few decades due to its various applications in different processes, such as ultrasonic cleaning, ultrasonic welding and ultrasonic assisted machining. In this thesis, design of the Langevin piezoelectric ultrasonic transducer is studied. In such transducers piezoelectric rings are sandwiched between front and back metals, clamped by a pre-stressed bolt. Besides clamping pre-stressed bolt also increase the tensile strength of the piezoelectric rings.
Initial dimensions were derived from basic one-dimensional wave equations associated with the equivalent circuit model. Mason’s electrical circuit method (E.C.M) was used in analytical modeling to find the dimensions of transducer. The design of ultrasonic transducers can be described as the process of finding the optimal design variables. These include the variables that determine the material and dimensions of the mechanical (acoustical) and piezoelectric elements, which minimize or maximize a certain number of parameters such as the input power and the output amplitude. These parameters also effect certain specific requirements such as resonance frequency, limitation of input voltage, applied pre-stress and geometric constraints.
The dimensions obtained from analytical modelling were used in performing finite element (FE) analysis to find modal analysis and harmonic analysis responses. Different geometrical constraints and conditions were used in (FE) analysis. FE models were created by using the FE software package COMSOL 5.1.
Transducer was fabricated and tested through electrical impedance analyzer. The results obtained from analytical model, finite element (FE) model and experimental testing are in good agreement with each other.
