柔性螺母连接结构参数影响分析  

Numerical Simulation and Structural Parameter Analysis of Flexible Nut Preload Connection

作　　者：冯伟 陆晓峰[1] 朱晓磊[1] 程可[1] 

机构地区：[1]南京工业大学机械与动力工程学院,江苏南京211816

出　　处：《机械设计与制造》2017年第12期107-111,115,共6页Machinery Design & Manufacture

基　　金：江苏省自然科学基金(BK20131411)

摘　　要：针对传统螺栓预紧连接中螺纹牙根部应力集中现象严重,螺栓易发生断裂失效的现状,设计出了一种柔性螺母结构。采用有限元计算方法,探讨了柔性螺母结构参数对螺栓连接应力分布的影响,并分析了相关作用机制,得到如下结论:相比于普通螺母连接,柔性螺母连接的螺栓第一道螺纹牙应力下降约为54%,应力集中程度明显减小,最大应力下降了37.1%,螺纹应力沿轴向分布趋于均匀,降低了螺栓发生疲劳断裂的风险;螺母螺纹牙的最大应力下降了14.7%,不均匀程度也有改善;支撑面倾角θ的存在,只是改变了螺栓连接系统的应力分布状态,其大小的改变对降低结构应力水平的影响不大;当D/e在1.15左右时,柔性螺母变直径处的应力集中可以减小甚至消除;柔性螺母连接的螺纹牙最大应力及其应力均匀化程度,与柔性螺母总厚度H的增加和支撑面宽度L呈正比,与六角段厚度h呈反比。In order to reduce the bolt fracture failure which caused by the stress concentration at the bottom of the thread in traditional preload bolt, a flexible nut was designed. The influence of structural parameters on the flexible nut stress distribution and the related mechanism of action were studied by the finite element method. The result shows that： compared with common preload connection, the flexible nut connection makes the stress down 54% at the bottom of the first thread, in bolt, and the maximum down 37.1%, the stress concentration is greatly improved and the risk of fatigue fracture about the bolt was reduced; The maximum stress at the bottom of the thread in nut down 14.7% and improve uneven stress distribution; The existence of the bottom angle 0 has little influence on reducing stress level, just change the stress distribution; The stress concentration at the variable diameter of flexible nut can be reduced or even eliminated when the value of Die is about 1.15; The maximum stress and the stress uniformity degree of flexible nut preload connection is proportional to the total thickness of flexible nut H and the edge length L, and inversely proportional to the thickness of hexagonal head h.

关 键 词：柔性螺母 螺纹应力 结构参数 

分 类 号：TH16[机械工程—机械制造及自动化]