harmonic vibration
6.The Poly Vinylidene Fluoride (PVDF) membrane was chosen to produce ultrasonic in transducer due to its higher sensitivity and better flexibility than other piezoelectric material. At the mean time, harmonic analysis to the PVDF film vibration was performed using ANSYS. The results show that the PVDF membrane can produce an ultrasound with a fixed resonance frequency.
8.Based on the assumption of periodic rubbing force in rotor system, the rubbing forces onto each node of rotor system are estimated by modal expansion technique and the sub-harmonic decomposition of residual matrix between faulty and faulty-free vibration signals of rotor system through FFT (fast Fourier transformation).
9.This paper presents the A/D sampling fitting method, the distorted point filtering method and the angular vibration simple harmonic diagnosis method respectively directing towards the key problems existing on signal measurement, signal processing, diagnosis methods, which establish the theoretical basis for studying practical and effective crankshaft angular vibration diagnosis system of ICE.
