剪切载荷下基于接触面滑移-黏着接触状态变化的螺栓松动特性

为研究螺栓松动特性，首先建立了带升角螺纹螺栓连接结构精细有限元模型，采用施加力矩法施加了初始预紧力，然后进行了螺栓松动特性仿真分析，提出了基于螺栓头接触面和螺纹接触面滑移-接触状态变化分析螺栓松动特性的方法，最后对该方法进行了准确性验证。结果表明：螺栓头接触面和螺纹接触面滑移-黏着接触状态变化规律能准确表征螺栓松动特性；两接触面滑移-黏着接触状态的交替变化是造成螺栓松动的主要因素，若始终存在黏着区域，螺栓松动不会发生；接触面处于滑移状态区域面积越大，增长速率越快，螺栓松动越容易发生；振幅越大、偏心距离越大，两接触面进入滑移状态的区域面积越大、速率越快，螺栓松动越容易发生；两接触面摩擦因数相差越大，螺栓松动越不容易发生，并存在一个两接触面摩擦因数匹配值范围，使螺栓松动最容易发生。

Bolt loosening characteristics based on change of slip-adhesion contact state under shear load

In order to study the bolt looseness characteristics, a fine finite element model of bolt connection structure with raised angle was established, and the initial preload was applied by means of applying torque method. Then, simulation analysis of bolt looseness characteristics was carried out, Finally, the accuracy of this method was verified. The results showed that: the change law of slip adhesion contact state of bolt head contact surface and thread contact surface can accurately characterize the bolt loosening characteristics; the alternate change of slip adhesion contact state of two contact surfaces is the main factor causing bolt loosening; if there is always an adhesion area, no bolt loosening occurs; the larger area of contact surface in the sliding state indicated the faster growth rate, the faster bolt loosening and higher likeliness of loosening; the larger amplitude and the greater eccentricity distance indicated the larger area and the faster speed of two contact surfaces entering the sliding state, and the easier bolt loosening; the greater difference of friction coefficient between the two contact surfaces indicated the higher likeliness of bolt loosening.