基于精确建模的横向振动工况下螺栓松动机理研究

横向振动是引起螺栓连接结构松动的重要原因。利用Hypermesh软件进行参数化建模,在建立带有螺纹升角的螺栓连接结构六面体网格精确有限元模型基础上,基于ABAQUS显式动态分析模块,通过接近实际工况的转角法拧紧螺栓,并施加横向正弦位移载荷,对横向振动下的螺纹连接结构松动情况进行多阶段、全过程有限元仿真分析,并设计了螺栓松动试验台进行螺栓松动实验,验证仿真方法的准确性。主要研究了横向振动前期螺栓扭转变形对螺栓松动情况的影响。结果表明,横向振动时的完全滑移先发生于支撑面处;在螺栓扭转变形完全回弹之前,预紧力的下降主要是塑性变形引起的,螺纹啮合处相对滑动不明显,此后,预紧力的下降主要是螺母回转引起的,螺纹处产生明显相对滑动,并提取了螺栓扭转变形回弹为0的节点。通过仿真和实验相结合的方法使分析结果更为准确。

Study on Bolt Loosening Mechanism in Vibration Condition Based on Precise Model

Lateral vibration is an important reason for loosening of thread connection structure. In this paper, the precise finite element model of the bolt connection structure with lead angle was established through parameterized modeling in Hypermesh with hexahedral mesh. Then, using the explicit dynamic analysis module in ABAQUS, the simulation analysis was made on the tightening process based on the rotation angle method of the bolt in near actual condition, and the transverse sinusoidal displacement load was applied to the connecting structure. The multistage and whole-process finite element simulation analysis of the screw connection structure with lateral vibration was realized. A single bolt looseness test equipment was designed, and a corresponding experiment was carried out to verify the accuracy of the simulation method. In this paper, the effect of bolt torsional deformation on bolt looseness in the prophase of transverse vibrations was studied. The results show that the complete slip of transverse vibration occurs first at the support surface. Before the bolt torsional deformation is fully rebounded, the preload is mainly caused by plastic deformation. At this time, the relative slip of the thread junction is not obvious. After this, the decrease of the pretension force is mainly caused by the rotation of the nut, which causes the obvious relative sliding in thread. In the simulation process, the point of the bolt torsional deformation rebound to 0 was extracted. The analysis results are more accurate through the combination of simulation and experiment.