螺栓法兰连接非线性刚度分析及参数影响研究

Research on Nonlinear Stiffness Analysis and Parameter Influence of Bolted Flange Connection

级间段对接面的连接刚度是航天器飞行安全性的重要因素,具有构造形式简单、装配可操作性优异等特点的螺栓法兰连接结构在航天器中得到广泛应用。针对外载荷作用下连接结构产生几何突变和结构连续性缺失,构件连接部位因此可能产生局部形变、应力与形变分布不均等问题,以及螺栓预紧力松弛与连接部位的疲劳和蠕变对连接可靠性的影响;提出利用无量纲刚度比和中空圆锥等效模型方法对螺栓非线性刚度进行分析,研究建立了螺栓法兰连接结构模型,利用有限元仿真计算软件,解决了预紧力、法兰厚度等因素与连接刚度的映射关系,同时也进一步研究外载荷作用下螺栓法兰的非线性刚度变化,为后续级间段对接分离设计提供参考。

The connection stiffness of the inter stage section junction surface is an important factor in the flight safety of the spacecraft. The structure of bolted flange connection is widely used in spacecraft due to the simple structure and easy operation. Due to the geometric abrupt change and lack of structural continuity of the connection structure under external load, local deformation, uneven distribution of stress and deformation may occur in the joint parts of the components, as well as the relaxation of the bolt preload and the fatigue and creep of the joint parts will affect the reliability of the connection. The nonlinear stiffness of bolts is analyzed by dimensionless stiffness ratio and hollow cone equivalent model method. The bolt flange connection structure model is established in this study, and the mapping relationship between preload, flange thickness and other factors and connection stiffness is explored and solved by finite element simulation calculation software, and the nonlinear stiffness change of bolt flange under external load is further studied, which provides reference for the subsequent inter-stage butt separation design work.