Document Type : Research Article
زنجان-مهندسی- گروه مهندسی مکانیک
Department of Mechanical Engineering University of Tehran
In this investigation, force-frequency effect in a square quartz resonator is studied. Based on the force-frequency effect, by insertion of diametrical forces, the natural frequency of thickness shear vibration mode in quartz resonators is changed. This criterion is of importance in designing quartz resonators and force sensors. In this paper, the frequency change of a square AT-Cut quartz crystal subjected to a pair of opposing forces on different points of its edge is studied experimentally. Also, the force-frequency effect in the square crystal is modeled by a previously developed mathematical-FEM model. The accuracy of the model is verified by the experimental results. Then, the model is applied for evaluating the force frequency effect in the crystal, and the frequency shifts in different loading coدfigurations is obtained. The new loading configurations are produced by moving the loading points along the edges, and by rotating the edges of the crystal around its thickness axis. Based on this , the loading configurations with maximum and minimum frequency shifts are obtained. Also, the design of quartz crystal force sensors having high sensitivity and also the crystal oscillator with high-frequency stability are discussed.