TEST STAND FOR LOW-FREQUENCY CALIBRATION OF ACCELEROMETERS

Current tools and techniques of vibration testing are applied in many areas of science and technology, especially in tool engineering where testing or calibrating exposure to the device under test or machine detail components is required. During engineering-seismological study to monitor technical state and analyze characteristics of structures, the authors widely used measuring equipment - seismo-accelerometers with the measured acceleration range from 10^-3 m/s² to several m/s² and the measured frequency range from 0.1 to 100 Hz. Changes in vibrations of the specified frequency range apply special requirements to the characteristics of measuring tools as well as to the techniques of their testing and calibration. However, in practice, the electrodynamic calibration vibro-stands operating in the frequency range from 5 Hz to 20 kHz with the amplitude up to several tens of m/s² got widespread use. The paper considers special aspects of calibration methodology of inductive and piezoelectric accelerometers by rotating the sensitive axis of the tested device in the earth’s gravitational field, gives the examples of tools and testing techniques by other methods using electrodynamic, mechanical, and hydraulic vibro-stands. The authors analyzed the advantages and disadvantages of the testing and calibration methodology under consideration compared to the analogous ones; described the design and operation of calibration stand based on the rotation of sensitive axis of tested device in the earth’s gravitational field; gave the formulas to calculate incoming acceleration acting along the sensitive axis of the device. For this reason, the authors proposed the stand’s kinematic diagram, the mathematical model of calibration methodology in the form of a structural diagram. The paper presents the experimental data of the tested device: the sensor’s amplitude-frequency response characteristic and phase-frequency characteristic. The authors compared the experimental data with the data obtained from the mathematical model of the calibration process.