裂纹盘式拉杆组合转子轴承系统动力学研究

For the rod-fastening rotor, the cracks have the complex shape and opening condition because of the large tighting force of the circumferentially distributed rods. The 3D cracks are built in the stress and dynamic model of the rod-fastening rotor directly, and the combined method is developed for carrying out stress and dynamic analysis of the cracked rod-fastening rotor. For the common complete rotor, only the stiffness variation of the rotating shaft is considered when analyzing the crack influence. However, the other dynamic factors such as the reforming effects of the rods and interfaces should be also investigated by studying how the cracks change the stress distribution of the rod-fastening rotor system. The above results and the crack propagation tracing method from the fracture mechanics are combined. Then the crack effects on the dynamic characteristics of the rod-fastening rotor bearing system are investigated. Finally, the important method and technique are proposed for analyzing the dynamic features for the complicated rotor bearing system with cracks. The corresponding experiments are carried out for proving the numerical data. This new method provides the theory evidence for discovering, avoiding and restraining the cracks on the complicated rotor. Therefore, this work has very important theoretical and practical meaning. Moreover, this project introduces the nonlinear numerical method for analyzing the 3D cracked rotor bearing system to break through the difficulty of applying the cracked rotor-dynamic study into the real complicated rotor. Generally, this project can promote the domestic level for understanding and designing the complicated rotor bearing system.

针对盘式拉杆转子大预紧力造成其裂纹形态复杂、开状态占优的特点，直接在盘式拉杆转子动力应力模型中建立三维裂纹，发展裂纹拉杆组合转子的应力及动力联合分析方法；不同于一般转子仅考虑裂纹造成转轴刚度降低对系统动力学的影响，重点研究裂纹通过改变拉杆组合转子应力分布造成拉杆及接触界面等关键动力部件参数重构，及其对系统动力学的影响规律和特殊机制；进而结合断裂力学中的裂纹扩展追踪方法，研究并掌握拉杆组合转子上裂纹扩展及其对系统动力学的影响规律。最终提供可用于此类复杂转子轴承系统裂纹缺陷分析判别的动力学分析方法和技术，并加以实验验证，为解决此处裂纹缺陷的发现、避免和抑制提供理论依据，因而具有十分重要的理论和现实意义。项目的意义还在于通过引入裂纹转子轴承系统三维应力动力非线性数值分析方法的研究，突破了目前裂纹转子动力学研究难以应用于实际复杂转子的瓶颈，从而提高我国对复杂转子轴承系统的认识和设计水平。

盘式拉杆组合转子轴承系统因其重量轻、易装配、冷却性能良好，而被广泛应用于燃气轮机，航空发动机等重要工业及国防装备中；裂纹作为旋转机械的一种典型故障形式，一旦出现常造成重大安全事故和经济损失，开展此类故障拉杆组合转子系统的动力特性研究，预防裂纹故障发生和加剧，对确保设备可靠运行，降低经济损失有重要意义。在本基金项目大力资助和支持下，分别从理论，仿真，实验三方面探究了含裂纹盘式拉杆组合转子轴承系统动力特性，首先分别建立了一维滑动和滚动轴承支承的盘式拉杆组合转子系统方程，搭建了动力仿真分析计算程序，考察了转速，不平衡量，裂纹深度等系统参数对系统动力特性的影响，一维滑动轴承裂纹系统的稳定性曲线发生偏移，在一临界转速附近出现双共振峰点，振动幅值和频率成分均发生变化，而一维滚动轴承非线性动力特性更加复杂多样；其次重点研究了三维拉杆裂纹建模方法，建立了三维含裂纹盘式拉杆组合转子系统有限元模型和三维裂纹系统动力方程，搭建了三维动力仿真分析程序，分析了裂纹对系统应力分布的影响，裂纹前缘应力强度因子变化规律，裂纹扩展引起的初始弯曲效应，研究了三维裂纹组合转子系统的动力特性，相比无裂纹系统，振动幅值增大及频率成分变化是裂纹转子系统的重要特征；初步形成裂纹盘式拉杆组合转子系统应力和动力联合分析方法；考察了典型加工缺陷对拉杆组合转子动力特性的影响；此外，设计并建立了裂纹盘式拉杆组合转子系统实验台，并进行了相关动力实验，实验表明振动加剧是裂纹转子系统的重要特征之一。相关研究可为解决此类组合转子系统裂纹缺陷的发现、抑制提供理论依据，为相关动力装备现场故障监测及安全运行提供一定的理论指导和工程参考，因而具有十分重要的理论和现实意义。资助期间发表及录用论文共15篇（其中SCI-13篇，EI-2篇），申请专利4项（授权1项，实质审查3项）；培养硕士或博士研究生共计10名；赴美国，日本等地参与国内外学术交流9人次。