裂纹转子通过参数共振区的瞬态特性

TRANSIENT BEHAVIOUR OF CRACKED ROTOR THROUGH PARAMETRIC RESONANCE RANGE

采用主谐波变换将通常的裂纹转子的运动微分方程变为了一种即可求定常运动 ,又便于研究非定常运动的方程。分别针对理想和非理想能源研究了裂纹转子加速通过参数共振区的瞬态振动特性。据此提出 ,转子在 2 ωc/ 3和 2

In order to diagnose the existence of a crack in rotating machinery,the transient vibration of a cracked rotor through parametric resonance range is investigated.By means of primary harmonic transformation,the normal motion equation of the cracked rotor is transformed into a new differential one.From direct solution of this equation,the amplitude of primary harmonic vibration can be obtained under nonstationary or stationary excitation.In respective consideration of ideal and nonideal sources of energy,it is found that:(1)Whether the source of energy is ideal or not,the largest amplitude of transient vibration near 2ω c/3 and 2ω c (Parametric resonance range) of the rotor with crack is bigger than that without crack (where ω c is the critical speed of the rotor without crack).And the deeper the crack,the larger the amplitude in the case of the ratio of crack depth to shaft diameter less than 0 4.(2)When the source of energy is ideal,the larger the acceleration,the less the largest amplitude of transient vibration through parametric resonance ranges of the cracked rotor.Because parametric resonance is the exclusive characteristic of cracked rotor according to the authors′ previous work,the authors believe that the transient vibration behaviors near 2ω c/3 and 2ω c may be a basis of diagnosing cracks on a shaft of rotating machinery.