Fundamentals Of Vibration Analyzers

Vibration analyzers are generally piezoelectric, and there are roughly two structural forms: ①compression type; ②shear type, the principle of vibration analyzer is to use the piezoelectric effect of quartz crystal and artificially polarized ceramics (PZT). designed. When a quartz crystal or artificially polarized ceramic is subjected to mechanical stress, charges are generated on its surface, and the resulting charge density has a strict linear relationship with the applied mechanical stress. At the same time, the mechanical stress is proportional to the acceleration value under the condition of a certain sensitive mass. Under certain conditions, the charge generated by the piezoelectric crystal is proportional to the acceleration value felt.

The generated charge is processed by the charge amplifier and other operations, and the output is the data we need. Q=dij·F=dij·ma In the formula: Q- the charge output by the piezoelectric crystal, dij- the second-order piezoelectricity of the piezoelectric crystal Tensor, m-sensitive mass of acceleration, a-value of vibration acceleration. The piezoelectric accelerometer of the vibrometer can withstand the output charge of the unit vibration acceleration value, which is called its charge sensitivity, and the unit is pC/ms-2 or pC/g (1g=9.8ms-2). The piezoelectric accelerometer of the vibrometer is essentially equivalent to a charge source and a capacitor. After simplifying the equivalent circuit, the voltage sensitivity of the accelerometer can be converted to Sv=SQ/CaSv-, and the voltage sensitivity of the accelerometer, mV /ms-2SQ-charge sensitivity of accelerometer, pC/ms-2Ca-capacitance vibrometer of accelerometer piezoelectric speed sensor, it is a piezoelectric speed sensor by adding an integrating circuit to the piezoelectric acceleration sensor, by adding acceleration signal Integrate one point, you can get the speed value of vibration!