外弯矩下螺栓法兰连接紧密性研究

Research on Bolted Flanged Connection Tightness under External Bending Moment

为准确分析螺栓法兰连接系统的紧密性,利用当量内压法﹑当量轴向力法和变形协调方程,研究外弯矩作用下螺栓法兰连接中的垫片压紧应力。分析结果表明:若利用当量内压法来计算,外弯矩等同于内压,相当于增大了系统的内压,但并不能体现出外弯矩作用下垫片应力在螺栓法兰连接系统分布的不均匀性;而利用当量轴向力法来计算,可以体现出整个系统在承受外弯矩作用导致的垫片应力沿管道圆周方向按余弦分布的不均匀性,并且垫片受拉侧和受压侧的压紧应力相差增大,其中受拉侧垫片应力减小,受压侧垫片应力增大,因此螺栓法兰连接的紧密性需重点考虑受拉侧的垫片应力。

In order to analyze the tightness of bolted flanged connection system accurately, the method of equivalent pressure, equivalent axial force and deformation compatibility equation were used to study the gasket compression stress of bolted flanged connections under the external bending moment.The analysis results indicate that when the method of equivalent internal pressure is used to calculate the gasket compression stress, the external bending moment is equivalent to the internal pressure and the internal pressure of the system is increased, but the calculation result can not reflect the uneven distribution of gasket stress in the bolted flange connection system under external bending moment.When the method of equivalent axial force is used to calculate the gasket compression stress,the calculation result can reflect the uneven distribution of gasket stress along the circumferential direction of the pipe under external bending moment, and the compression stress difference is increased between the tension side and compression side of the gasket.Among them,the gasket stress is decreased on tension side and increased on compression side, so the gasket stress on tension side must be considered closely when studying the tightness of the bolted flanged connection.