拧紧策略对航空发动机单螺栓连接预紧力的影响

The problems of poor pre-tightening force of bolts and low control precision during the assembly process of aero-engines. The experimental research on tightening process of single-bolt joint was carried out. The influence of different tightening strategies on the size and stability of pre-tightening is analyzed, including the study of tightening speed and methods such as torque-control method and angle-control method. Based on the torque-control method, the effect of multi-step tightening on the pre-tightening force is studied. Aiming at the single bolt and the typical flange bolt connection structure of aero-engines, the short-time attenuation pattern of the bolt pre-tightening force is explored. The results show that the standard deviation of the pre-tightening force of angle-control method is about one-third of the torque-control method during repeated tightening. By using the angle-control method, multi-step tightening and increasing the tightening speed, the tightening torque coefficient K can be stabilized. The pre-tightening force dispersion degree can be reduced and the single bolt pre-tightening force control precision can be improved. It is also found that the pre-tightening force will attenuate in a short time after the tightening is completed. The most of the attenuation occurs in the first 5~10 minutes, accounting for about 80% of the total attenuation. It will enter steady state after 20~30 minutes.