Study of the phase characteristics of vibration sensors and conditions of orthogonalization of their measuring basis for the systems of vibration control and vibration testing of materials

Abstract

To identify the most vibration-sensitive structures of the materials during vibration tests, it is necessary to determine the vibration vector in an orthogonal basis The effectiveness of the tests depends on the accuracy of the vector measurement. The transverse sensitivity of tri-axial vibration transducers, which have found vast application in various vibration measuring and material testing systems, leads to increased measurement errors and limits the frequency range of measurements. The errors can be reduced to almost zero using the proposed method of electronic orthogonalization, which involves rotation of the sensitivity vectors until they coincide with the orthogonal basis, resulting in zero transverse sensitivity. This approach has been successfully developed and works rather well in the low frequency band of the vibration transducer frequency response, wherein the amplitude-characteristics are linear and there is no phase shift in the channels. An emphasis is made on the influence of the phase characteristics of vibration sensors on the formation of orthogonalizing matrices that determine the requirements for an orthogonalizer. The structure of the installation for automated recording amplitude-frequency and phase-frequency responses of the vibration transducer, methodology and results of experimental study of a tri-axial piezoelectric accelerometer (TPA) with one inertia element and oblique-angle measuring basis are presented. The results obtained under vibration activated in three mutually perpendicular directions along the measuring axes show that the transducer measuring system is properly designed to provide for effective broadband orthogonalization of the measuring basis. The results obtained can be used to develop orthogonalizing transducers that eliminate transverse sensitivity in a wide frequency range, as well as to improve the design of sensors and their metrological characteristics.