八角垫高压密封结构预紧力分析和试验研究

石油、化工、核电行业法兰螺柱预紧过程中, 螺柱预紧应力计算与保证垫片应力均匀分布的预紧方法是工程实际中值得研究的问题. 该文通过对螺柱垫片系统进行物理结构分析, 受力过程分析, 提出了一种基于垫片线性变形的螺柱应力分布数学模型及预紧方法. 研究表明模型计算结果与试验结果相符合, 满足实际规律. 因此, 该数学模型能用于分析预紧过程中螺柱应力变化情况；计算出螺柱具有相同密封应力的初始载荷及只需一次加载就可以达到理论密封应力的预紧优化方法. 这使得在预紧过程中不必采用边预紧边测试应变的方法来进行指导, 更有效保证密封性能.

RESEARCH ON THE STRATEGY OF PRELOAD AND EXPERIMENTAL STUDY ON OCTAGON GASKET SEALING STRUCTURE FOR HIGH PRESSURE VESSELS

The distribution of stress and the method of same stress for uniform bolts preloads is worthy of studying during the process of tightening a flange. By analyzing the physical structure and its loading process, a mathematical model is proposed for studying the stress of bolts. The model is based on a liner-elastic model about a gasket and can predict both the scatter in bolt preloads and the ?nal clamp load distribution after the completion of joint tightening of a vessel ?ange assembly. Experimental veri?cation is provided for the validation of the mathematical model. Experimental and analytical results are presented and discussed. The model provides a good prediction for the ?nal clamp load in the join. Therefore, the novel formulation can be used to calculate and estimate the variation of bolt stress and could be used for developing tightening strategies that would achieve a more uniform clamp load in the ?ange at the initial assembly. Moreover, the model makes the process of preload without testing strain and ensure the sealing performance.