惯性非对称转子系统动力特性及安全设计策略

Dynamic Characteristics of Inertia Asymmetry Rotor and Safety Design

关键词:  惯性非对称  模态特性  失稳  响应  安全设计策略

Key words:  Asymmetry of inertia  Modal characteristics  Instability  Response  Safety design

摘要:

本文旨在分析惯性非对称转子结构的动力特性，主要包含多频特性、稳定性，并针对转子的失稳提出相应的安全设计策略。建立惯性非对称转子模型及其动力学方程，通过Hill无穷行列式建立非对称转子模态特性分析方法，分析惯性非对称转子系统的模态频率、稳定性；计算减速过程中转子的响应特性，进行试验验证并提出惯性非对称转子系统的安全性设计策略。研究表明：惯性非对称转子系统在频率上具有多频特性和频率耦合现象。频率耦合对应的转速区内转子系统发生失稳。相比一般转子系统，惯性非对称转子系统的临界转速为一条临界转速频带，该频带与频率耦合转速区相对应，造成转子系统在临界转速附近响应放大，临界转速区扩张。针对不同工程问题，可以通过增加转子阻尼消除失稳区、降低转子系统刚度避开临界转速的安全设计策略。

Abstract:

The paper aims at analyzing the rotor dynamic characteristics with inertial asymmetric， including multi-frequency characteristic and stability characteristic， and proposing corresponding safety design strategies for the rotor instability. An inertial asymmetric rotor model and dynamic equations are derived and the modal analysis method of the asymmetric rotor based on the Hill infinite determinant is established. The modal frequency and stability of the inertial asymmetric rotor system is obtained. The response characteristics of the rotor during the deceleration process is calculated and verified by experiment. The safety design strategies of inertial asymmetric rotor system are proposed. The results reveal that due to the asymmetry of inertia， the dynamics for rotor is characterized by a multi-frequency and lock-in frequency type of behavior， which is possible to lead to the rotor’s instability. Compared with the ordinary rotor system， the critical speed of the inertial asymmetric rotor system is a critical speed band， which corresponds to the frequency lock-in region， causing the response amplification of rotor system near the critical speed and the expand of critical speed region. For different types of engineering problems， the safety design strategies can be used to avoid resonance by reducing rotor’s support stiffness or increasing damp to eliminate instability region.