转子系统碰摩约束模型与振动响应分析

Constraint model and vibration response analysis of rotor rub-impact

针对转静子碰摩的典型力学特征,从碰摩对转子产生附加约束的角度提出了碰摩力学模型,基于该约束模型,分析了转子系统碰摩过程中的共振区间扩展、振幅跃迁与不稳定接触等响应特征与机理.研究了力学特征参数对转子碰摩振动响应的影响,结果表明附加约束刚度提升使得系统共振区间与不稳定接触区间增大,而转静子间摩擦系数升高造成系统共振区间减小与振动响应幅值的降低.建立了具有航空发动机结构特征的碰摩分析模型,仿真结果表明,除碰摩约束造成的共振区间扩展外,具有结构特征的转子碰摩响应还与碰摩位置及模态振型密切相关.碰摩程度较轻时,转子瞬态响应表现出拟周期振动的特点,而碰摩程度严重时,转子运动趋向不稳定,响应特征更接近约束模型.

Considering the additional constraints induced by rub-impact,a mechanical model was proposed for typical mechanical characteristic of rub-impact. Based on the constraint model,some characteristics in response such as resonant interval extending,amplitude jumping and contact instability were analyzed.Impact of typical mechanical characteristic parameters on rotor response during rub-impact process was studied. It is found that additional constraint stiffness will cause the extension of the resonant range and instable contact region,while greater friction coefficient between rotor and stator causes the decrease of the vibration response and resonant range. A rub-impact analytical model with structure features of aero-engine was built,numerical simulation shows that in addition to the resonance range extension caused by additional constraints,characteristics of rotor response are closely related to rub location and mode shapes. System＇s response shows characteristics of quasi-periodic in soft rub-impact,while rotor movement tends unstable and closer to the mechanical model in heavy rub-impact.