以典型带中介轴承的发动机高压转子系统为研究对象，提出一种基于多体接触瞬态动力学的发动机转子支承不同心故障等效模拟分析方法，建立了高压转子-轴承-局部支承系统的多体动力学模型。在轴承受力分析的基础上，通过对接触运动状态非线性模拟和支承结构柔性化，研究了单个滚珠、滚珠与轴承外圈、轴承外圈与支承结构的瞬态接触力、力矩以及支承结构振动响应，得到不同心故障特征的产生机理和传递规律。结果表明：压紧区、松脱区以及单个滚动体与内外圈的相对位置变化产生的复杂相互作用是滚动体接触力复杂频率成分产生的直接原因；全部滚珠与外圈的瞬态接触力合力及合力矩是产生不同心故障特征的激励源；轴向振动工频及倍频是不同心故障的典型特征；轴向和径向2倍频、3倍频相对工频幅值的大小可表征不同心故障的严重程度。本文所得结果可为燃机不同心故障分析诊断提供参考。

An equivalent simulation and analysis method for the bearing misalignment of an engine rotor based on multi-body transient contact dynamics was proposed.The multi-body dynamic model of the high-pressure rotor-bearing-partial support structure was developed.The transient contact forces and moments between a single roller and the outer ring, between all rollers and the outer ring, as well as between the outer ring and the support structure were analyzed considering the non-linearity of contact and the flexibility of support structure.The vibration response of the support structure was studied and the generation mechanism and transmission of bearing misalignment fault were investigated.The results show that the complex interactions, caused by the variation of the relative position of the single roller to the rings and also by the rollers locating in compacting or loosening regions, are the direct reason of the appearance of complex frequency components in the contact force.The misalignment excitations are from the transient resultant contact force and torque between all the balls and the outer ring.Harmonic frequency components of axial vibration are the typical characteristics of misalignment faults and the magnitudes of the double and triple harmonics of the axial and radial vibration can represent the severity.The results provide reference for the diagnosis of misalignment in gas turbines.