动载实验中压电晶体应力量计的设计与应用

各种压电器件广泛用于电子工业、信息传输、医学诊断等许多领域,以实现能量转换、传感、驱动、频率控制等功能. 特别地,压电晶体以其高频响的压电效应,在动载实验中用于动态应力的测试. 利用其特有的各向异性特性,通过设计特殊的切型方向,可以实现对不同应力的测试. 本文通过分析各向异性晶体的特性,从压电效应的基本原理出发,导出了利用各向异性晶体作为剪应力量计的设计思想,并给出了两种典型的动态剪应力计:17.705°Y 切石英和165.44°Y 切铌酸锂晶体. 

DESIGN AND APPLICATIONS OF PIEZOELECTRIC CRYSTALS TRANSDUCER IN DYNAMIC EXPERIMENTS

Various piezoelectric crystals are widely used in many fields such as electronics industry, information transmission to achieve energy conversion, frequency control or as sensors and so on. With the unique piezoelectric properties and high frequency response, piezoelectric crystals have been used as force transducer in high strain-rate experiments to test dynamic stresses. Among them, quartz crystal has been used in split Hopkinson pressure bars (SHPB) for axial stress measurement, and in gas gun experiments as the shock wave pressure transducer. Meanwhile, with the anisotropic properties, it is possible to design a special rotated cut direction for the crystals to get a required piezoelectric response to selected stress. In this paper, we propose a design of shear transducer in split pressure-shear Hopkinson bars (SHPSB), by analyzing the wave propagation characteristics with a desired pure vibration mode in anisotropic crystals, and the basic principles of piezoelectric effect with independent response to the shear stress. Two typical shear transducers, which are made of 17.705° rotated Y-cut quartz and 165.44° rotated Y-cut lithium niobate respectively, are achieved finally.