螺栓法兰连接系统的热应力场

Thermal stress of bolted flanged system

利用有限元软件ABAQUS建立了螺栓法兰连接系统的实体模型,采用热结构耦合分析方法,研究了法兰公称直径为100mm的螺栓法兰系统的温度场及其应力场,以及在预紧力和温度梯度操作条件下螺栓等效应力、轴向应力、径向应力和切向应力的变化关系.结果表明,温度场对螺栓轴向两端的应力影响较大,当内壁温度为100℃时螺栓头靠近法兰一侧的等效应力增加了250MPa,螺栓上靠近法兰一侧的螺纹的等效应力增加100MPa,而温度场对螺栓远离法兰一侧的螺纹的应力影响很小,说明设计时应重点考虑热应力对靠近法兰一侧的螺纹与螺栓头的影响.

The real model of bolted flanged system was established by finite element software ABAQUS.The temperature field and stress field of bolted flanged system were analyzed using thermal-structure coupling analysis.Changes of equivalent stress,axial stress,diameter stress and tangential stress of bolt under combined preload and temperature gradient were studied.Results show that the temperature field significantly increases the stress at two ends of bolt;the maximum equivalent stress at bolt head closing to flange increases 250MPa and equivalent stress of thread in bolt closing to flange increases 100MPa when the inner wall temperature is 100℃;temperature field has few influences on stress at thread which is away from flange in bolt.It illustrates that the influences of thermal stress on bolt closing to flange should be stressed in engineering design.