法兰环切口对连接力学行为的影响分析

EFFECT OF THE CUTOUT IN THE FLANGE RING ON MECHANICAL BEHAVIORS OF BOLTED JOINTS

按工程简化方法设计的法兰连接结构偏于保守,不能满足结构轻量化的设计要求。根据受载时法兰环中应力分布不均匀的情况,可以通过在法兰环上预制切口提高结构效率,为研究在法兰环上预制切口对连接力学行为的影响,采用三维非线性有限元法,对三种带切口和无切口法兰进行力学分析和讨论。研究结果表明,预制切口对连接力学行为有影响;预制切口后,局部连接刚度改变,法兰弯曲和扭转变形增大,连接面张口间隙和弯曲应力均增大,切口体积是影响上述变化的主要因素;预制切口对接触面应力分布有影响,切口能够改善接触应力的均匀化程度。

Bolted flanged joints designed based on present available engineering design rules can＇t be effective lightweight structures.There is non-uniform stress distribution in the flange ring under the operation load.Cutouts in the ring may improve structural efficiency.Three dimensional nonlinear finite element analyses were used as tools to ensure the effect of cutout on mechanical behaviors of flanged joints.Totally four flanged joints,three with cutouts and one without,were analyzed to get detailed stress and displacement.The results show that the cutout has obvious effect on joints.The stiffness of the flange ring decreases with cutouts and the bending and rotation displacement of the flange increase.Contact opening displacement at the joint interface and bending stress in the flange fillet also increase.The cutoff volume is the major reason for those variations.Contact stress variation between flange faces is also changed with cutouts.