Quantum mechanics

Control (management)

Chaotic

Engineering

Bifurcation

Coupling (piping)

Radio frequency

Telecommunications

Vibration

Computer science

Acoustics

Fault (geology)

Seismology

Geology

Mechanical engineering

Physics

Nonlinear system

Amplitude

Optics

Artificial intelligence

Structural engineering

Sideband

Bifurcation diagram

Control theory (sociology)

Mechanics

Engineering Failure Analysis

Due to the influence of signal modulation and multi-stage coupling, the fault diagnosis of multi-stage planetary gear system is difficult. In this paper, a dynamic model of multi-stage planetary gear system containing sun gear crack is proposed from the perspective of nonlinear dynamics to study the failure mechanism and dynamic characteristics of tooth root crack. The mesh stiffness with root crack is calculated by using the modified energy method. By means of global bifurcation diagram, RMS curve, phase diagram, Poincare map, time series diagram and FFT spectrum, the dynamic responses of the system with and without fault are analyzed and compared. The results show that there are differences in the impact of crack failure on the dynamic characteristics at different rotational speeds. The crack disturbance will cause an abrupt change in the vibration amplitude of the system, which can excite the system into chaos from a quasi-periodic state. The system tends to be unstable due to crack failure, which is manifested by irregular expansion of the attractor, divergence of the phase trajectory, periodic pulses in the time series diagram, and sideband frequencies with the sun gear fault characteristic frequency as interval appearing around the meshing frequency. The chaotic motion range should be avoided during crack fault diagnosis.

Dynamic modeling and analysis of multistage planetary gear system considering tooth crack fault