School of Mechanical Engineering, College of Engineering, University of Tehran, P.O. Box 11155/4563, Tehran, Iran.
A clear understanding of force-frequency eect is essential for enhancing the accuracy of quartz crystal resonators and sensors. Several analytical models have been developed to predict the frequency change of piezoelectric crystals like quartz due to forcefrequency eect. According to these models, frequency change is due to initial mechanical stresses caused by the application of diametrical forces. Usually, the anisotropy and piezoelectricity of quartz are neglected in determination of stress bias and in force-frequency equation. In this research, we quantied the eect of anisotropy and piezoelectricity of ATcut quartz on the force-frequency coecient. To this end, besides using the mathematical models, a nite element code, based on linear and nonlinear Lagrangian formulations, was developed. The FEM showed more reliable results than dierent analytical approaches. We found that the force-frequency coecient is more sensitive to the anisotropy than to the piezoelectricity of quartz. By considering the anisotropy, the standard error of the force-frequency model decreased from 12.4 E-15 (ms/N) to 5.75 E-15 (ms/N). On the other hand, anisotropy can modify the shape of force-frequency curve at force azimuth angles close to 0.