﻿ 复杂轴承支撑结构动力学特性的有限元方法研究
 舰船科学技术  2017, Vol. 39 Issue (2): 92-96 PDF

Research on dynamic characteristics of the complicted bearing supportstructures by finite element method
ZHU Dan-chen, ZHANG Yong-xiang, PAN Dong
Department of Power Engineering, Naval University of Engineering, Wuhan 430033, China
Abstract: Complicted bearing support structures are composed of several substructures, which forming the interface. Study shows that these interfaces have a significant influence on the dynamic characteristics of the system, the damping and reflection of the vibration signal due to the interface is a big problem in the process of signal extraction. Aiming at solving this problem, a finite element model of the bearing support structure is established. By using Ansys Workbench, the modals and transfer function of the model are calculated. Using the method of comparative study with the whole structure and the impact of the change of bolt pre-tightenning force is considered. The characteristics of the response when subjected to shock loading are analyzed. The results show that with the increase of pre-tightenning force, the modals increase, the attenuation of high frequency signal is more obvious and the bearing fault signal is difficult to be transmitted in the complex transmission path.
Key words: complex bearing support structure     finite element model     vibration transfer characteristic
0 引言

1 有限元模型的建立

 图 1 复杂轴承支撑结构 Fig. 1 Complex bearing support structure

2 模态计算分析

 $T = KFd \text{。}$ (1)

 图 2 整体结构的前 6 阶振型 Fig. 2 The first six vibration modes of the whole structure

 图 3 螺栓连接结构的前 6 阶振型 Fig. 3 The first six vibration modes of bolt connection structure

3 复杂轴承支撑结构传递特性分析

 图 4 结构中激励点、响应点分布图 Fig. 4 The distribution of excitation point and response point in the structure

 图 5 整体结构的幅频特性曲线 Fig. 5 The amplitude frequency characteristic curve of the whole structure

 图 6 拧紧力矩为 20 Nm 时的幅频特性曲线 Fig. 6 The amplitude frequency characteristic curve when tightening torque is 20 Nm

 图 7 轴承故障模型信号 Fig. 7 Bearing fault signal

 图 8 整体结构测点 1 的加速度时域图 Fig. 8 The acceleration time domain of the whole structure in measuring point 1

 图 9 整体结构测点 2 的加速度时域图 Fig. 9 The acceleration time domain of the whole structure in measuring point 2

 图 10 考虑螺栓连接的支承结构测点 1 的加速度时域图 Fig. 10 The acceleration time domain of the structure in measuring point 1 when bolt connection is considered

 图 11 考虑螺栓连接的支承结构测点 2 的加速度时域图 Fig. 11 The acceleration time domain of the structure in measuring point 2 when bolt connection is considered

4 结语

1） 螺栓连接结构的存在对系统模态有着较大的影响，相比而言，整体结构的各阶模态值普遍偏高；随着螺栓预紧力的增大，系统的各阶模态值也呈增大趋势，但差距并不明显。

2） 螺栓连接结构使得信号在高频处的衰减作用要更加明显，而且随着频率的不断提高，螺栓结构对信号的衰减作用越来越明显，这一特性在整体结构中是难以体现的。

3） 复杂结构设备轴承支撑结构中由于存在多处螺栓连接结构，信号从结构内部传递到机匣处需经过复杂的传递路径。当轴承故障信号从内部向外传递时，在机匣处测得的响应信号已经难以体现信号原本的特性，这在一定程度上增加了有效信号提取的难度，影响了故障诊断的准确性。

 [1] 陈果. 含碰摩故障的新型转子-滚动轴承-机匣耦合动力学模型[J]. 振动工程学报, 2009, 22 (5): 538–535. [2] 赵帅, 王克明, 慕鹏, 等. 螺栓联接结构振动特性有限元分析方法的研究[J]. 沈阳航空航天大学学报, 2012, 29 (2): 18–22. [3] NARUSE T, SHIBUTANI Y. Nolinear bending stiffness of plates clamped by bolted joints under bending moment[J]. Journal of Solid Mechanics and Materials Engineering, 2012, 6 (7): 832–843. DOI: 10.1299/jmmp.6.832 [4] 陈长盛, 王强, 柳瑞锋, 等. 螺栓连接对结构模态及传递特性影响研究[J]. 振动与冲击, 2014, 33 (2): 178–182. [5] 赵猛, 张以都, 马良文, 等. 装配结构模态仿真与实验对比研究[J]. 振动与冲击, 2005, 2 (1): 28–30. [6] 温淑花, 张学良, 武美先, 等. 结合面法向接触刚度分形模型建立与仿真[J]. 农业机械学报, 2009, 40 (11): 197–202. [7] 温淑花, 张学良, 文晓光, 等. 结合面切向接触刚度分形模型建立与仿真[J]. 农业机械学报, 2009, 40 (12): 223–227. [8] 黄志新, 刘成柱. ANSYS Workbench14.0超级学习手册[M]. 北京: 人民邮电出版社, 2013. [9] 艾延廷, 武威, 田晶, 等. 被联接件形式对结构模态及传特性影响的研究[J]. 科学技术与工程, 2014, 14 (4): 46–50.