循环横向载荷作用下旋转松动期内螺栓法兰连接结构松动行为

Looseness Behavior of Bolted Flange Connections under Cyclic Lateral Load During Rotation Loosening Period

关键词:  横向载荷  螺栓法兰连接结构  旋转松动期  松动行为  影响因素

Key words:  Transverse load  Bolt flange connection structure  Rotation loosening stage  Loose behavior  Influence factor

摘要:

为研究横向载荷下旋转松动期内螺栓法兰连接结构松动行为，建立了多种带螺纹升角螺栓法兰连接结构精细有限元模型，分析了不同拧紧工艺对螺栓预紧力大小及散差的影响，进行了松动条件理论分析，从理论上揭示了螺栓松动现象发生的所需条件，并基于预紧力变化和螺纹接触面、螺栓头接触面黏着-滑移接触状态变化情况对循环横向载荷下旋转松动期内连接结构松动行为进行了仿真计算，主要系统分析了螺栓初始预紧力、横向载荷幅值、螺栓位置、螺栓个数、螺栓直径、接触面摩擦系数、止口紧度影响因素对连接结构松动行为的影响规律。结果表明：初始预紧力越大、横向载荷幅值越小、螺栓个数越多、接触面摩擦系数越大、螺栓直径越大、止口紧度越大，连接结构松动越难发生；存在一横向载荷幅值临界值，当小于此临界时，各螺栓均不发生松动，大于此临界时，有螺栓发生松动；存在一螺栓位置值，使连接结构松动最不容易发生。

Abstract:

In order to study the loosening behavior of bolted flange connections during the period of rotational loosening under lateral load， the fine finite element models of various flange connections with threaded rising angle bolts were established， the effects of different tightening processes on the magnitude and dispersion of bolt preload were analyzed， the loosening conditions were theoretically analyzed， and the required conditions for bolt loosening were revealed theoretically. Based on the change of preload and the change of adhesion slip contact state of thread contact surface and bolt head contact surface， the loosening behavior of connection structure during rotational loosening period under cyclic transverse load was simulated. The effects of bolt initial preload， transverse load amplitude， bolt position， number of bolts， bolt diameter， friction coefficient of contact surface and stop tightness on the loosening behavior of connection structure were systematically analyzed. The results show that the greater the initial preload， the smaller the transverse load amplitude， the more the number of bolts， the greater the friction coefficient of the contact surface， the larger the bolt diameter， and the greater the tightness of the seam， the more difficult the looseness of the connection structure is to occur. There is a critical value of transverse load amplitude. When it is less than this critical amplitude， all bolts will not loosen. When it is greater than this critical amplitude， bolts will loosen. There is a bolt position value， which makes the looseness of the connecting structure the least likely.