Frequency-temperature behavior of flexural quartz resonators by means of Timoshenko´s model

The frequency of a flexural resonator and its frequency-temperature behavior usually are computed by Bernoulli´s classical approximation. This approach is valid for beams with a large length-over-thickness-ratio. For shorter beams, the effects of shear stress and rotary inertia may play a significant role for temperature-compensated resonators. These effects have been taken into account for isotropic beams. The aim of this paper is to discuss the extension of the shear coefficient in the case of an anisotropic material and to compute the frequency-temperature characteristic of an (XYt)thetas cut resonator when the shear stress and the rotary inertia have been taken into account. Comparisons between the classical approximation arid this treatment are given for quartz. Furthermore, the numerical predictions obtained by means of different sets of data available for thermal sensitivities of elastic coefficients are compared