Test technique for dynamic characteristic of rotor axial force on aero-engine

Taking the axial force of thrust bearing on aero-engine as research object，and based on the measurement principle of stress ring method，a new testing technique applicable to dynamic characteristic of rotor axial force was developed.A stress ring transducer with fan-shaped fulcrum structure was designed on the basis of clamped beam model.The rationality of the special stress ring structure was validated by theoretical analysis and finite element simulation； and the measuring sensitivity and static characteristic index of stress ring transducer were quantified and represented.The trial run results of the aero-engine showed that non-negligible dynamic alternating load existed in rotor axial force，and its peak value accounted for 6%-29% of steady-state value.The results of frequency domain analysis indicated that the vibration source of axial force dynamic alternating quantity consisted of the fundamental frequency of rotating speed and the 2 times frequency of rotating speed，as well as 34，68 Hz.The phase analysis reveals that time domain waveform of stress ring circumference measuring points has phase synchronization change due to the dynamic alternating load caused by 34 Hz and 68 Hz，which met the manifestation of axial vibration，while the fundamental frequency and the 2 times frequency of rotating speed could have precessional motion changes along the stress ring circumference，meeting the manifestation of rotor imbalance failure.