A critical evaluation of the determination of high-order elastic stiffnesses of quartz

The paper deals with the critical evaluation of the methods used in our previous papers [1], [2] concerning with determination of the high-order material constants in the quartz. We have determined the effective elastic constants of 4(th) order using a measurement of the intermodulation products, and measurement of drive level dependence of resonant frequency of quartz resonators. The computer based - method of solution of the set of equations gives an access to obtain the effective non-linear stiffnesses of 4th order. The measurements and computer solutions are performed on different Y-cuts resonators, both for quartz and gallium phosphate resonators, vibrating in fundamental thickness shear mode. The experimental results are discussed.