横向载荷作用下螺栓连接松动过程研究

针对横向载荷作用下的螺栓连接松动过程开展研究，给出了面向螺栓松动仿真的建模方法，分析了循环往复载荷作用下接触状态与残余预紧力的变化规律，并研究了载荷作用位置、幅值和频率对螺栓连接松动的影响。分析结果表明：在横向循环载荷作用下，残余预紧力出现交替的上升与下降；螺纹接触面先于螺头承压面进入滑移状态；横向载荷作用在上板或下板对松动没有影响；载荷幅值是影响松动的主要因素，载荷幅值越大松动越容易发生，而加载频率对松动影响较小。本研究分析结果与Junker试验结果一致性良好，可推广到复杂载荷条件下的应用。

Study on Loosening Process of Bolted Joints Under Transverse Load

Loosening is one of the causes of bolted joints failure. It is of great significance to understand the bolt loosening process in structure design. The loosening process under transverse cycle load was analyzed. The modeling method for bolt loosening simulation was given to investigate loosening process by analyzing changes of contact states and residue preload. Several factors such as dynamic shearing load position, amplitude and frequency were taken into account. The results show that the residual preload of the bolt rises and declines alternately during the loading cycles under transverse cycle load. Complete thread slip has occurred prior to head bearing surface slip. There is no difference on loosening rate whether the load acting on the upper or lower plate. Vibration amplitude is the main factor affecting loosening rate and the greater the excitation amplitude is, the easier the occurrence of loosening will be. Vibration frequency is proved to have little effect on loosening rate. The results agree with the Junker test results and can be extended to complex load conditions.