金属平垫片螺栓法兰接头泄漏预测的可行性研究

A Feasibility Study of Leakage Prediction for the Bolted Flange Joints with Metal Flat Gasket

螺栓法兰结构在服役过程中,不可避免的受到载荷和温度波动的影响,引起垫片应力发生变化,进而引起泄漏。因此,预测法兰接头的泄漏对于保障正常运行至关重要。运用ABAQUS有限元软件,建立了螺栓法兰结构的三维有限元模型,模拟了法兰结构的预紧-加载过程,基于泄漏率的概念,采用平均应力法计算垫片应力,分析了垫片应力和螺栓力分布及变化规律。研究结果表明,垫片应力同螺栓中应力存在单调对应关系,即可以测量螺栓中应力预测螺栓法兰结构的泄漏问题,以减少工程中螺栓法兰结构的泄漏问题。

Subjected to the fluctuation of the temperature and pressure, the gasket stress of the bolted flange joints would redistributes which lead to the leakage accident occurred from the joints. It is of great significance to predict the probability of the leakage of the bolted flange joints. The preload and loading process of the bolts are simulated by the 3-D finite element model established by ABAQUS software. Based on the concept of leakage rate, the stresses in the gasket and bolts are analyzed. The gasket stress is calculated by the average stress approach. The results show that the corresponding relation exists between the gasket stress and residual bolt stress. It means that it is feasible to predict the leakage probability of the bolted flange joints by monitoring the residual stress in the bolt.