Effects of Two Cracks in Shafts on Dynamic Characteristics of Two-span Rotor-bearing System

摘要

The nonlinear dynamic model of two-span rotor-bearing system with two cracks in shafts is set up,and the effects of two cracks in shafts on dynamic characteristics of the rotor-bearing system are analyzed.Along with the increase of the crack depth in first span,the chaotic and periodic motions increase,and the quasi-periodic motion decrease in the supercritical rotate speed.There are harmonic elements of 1/4,1/2 and 3/4 frequency division within the sub-critical speed range at different crack depths.There appears the frequency doubling resonance obviously when the crack depths are larger.Along with the increase of the crack depth in second span,the main influences to the responses of system are in the second span.The chaotic regions increase and then decrease and the periodic motions region increase in the sub-critical rotate speed range.