The results on forced electromechanical vibrations of piezoceramic half-disks in some range of frequencies are systemized and generalized. Much attention is drawn to new experimental methods for studying the amplitude-frequency and phase-frequency characteristics Keywords: piezoceramic half-disk, forced vibrations, admittance, amplitude-frequency and phase-frequency characteristics, phase ratioIntroduction. Problems of the resonant and forced vibrations of piezoelectric bodies have been in the focus of attention of scientists for many decades due to the high efficiency of electromechanical energy conversion [1-5, 7-9, 11-16, 18-30, etc.]. In tests on piezoelectric vibrators, the mass, static capacitance, dimensions, characteristic (resonant and antiresonant) frequencies of and the voltage drop across the piezoelectric element and/or the pull-up resistor are directly measured [7-9, 11-15, 19-23, etc.] to determine, by various methods, the components of admittance and the active (real) and reactive (imaginary) components of the material constants. There are no methods for the direct measurement of the active and reactive components of admittance; therefore, they have to be determined indirectly, i.e., calculated by various approximate formulas.The recent studies [28][29][30] show that the behavior of piezoelectric vibrators at high power strongly depends on the type of electric loading. The admittance-frequency response at voltage of constant amplitude is essentially nonlinear, including abrupt drops and jumps. Such nonlinearity is absent if the current is of constant amplitude [30].The quest for ways to measure the electroelastic and viscoelastic coefficients of piezoelectric vibrators is still ongoing. A method for determining the Q-factor and piezoelectric modulus by differentiating the frequency-dependent active component of the admittance with respect to frequency is described in [5]. An interesting combined experimental/numerical procedure was proposed in [1] where the active components of the electroelastic material constants of piezoceramics are determined by measuring the resonant frequencies of various vibration modes of a rectangular rod from which a square plate is then cut out. In [25,26], it was shown that the values of the Q-factor at resonance (Q a ) and antiresonance (Q b ) are different, and Q a < Q b .Here we further develop experimental methods by searching ways of studying phase-frequency responses in some frequency range, generalizing and comparing resonance/antiresonance methods, and assessing the accuracy of values of some most frequently used parameters. For example, we will show that the classical two-port network (Mason circuit) provides tolerable errors only at characteristic frequencies, whereas in frequency ranges below resonance and between neighboring resonances there are considerable phase shifts between the current and the voltage drop across the piezoelectric element. An advanced Mason circuit with an additional switch allows reducing the effect of phase shifts. Combining the re...
