Influence of Tightening Strategy on Pre-tightening Force of Aero-engine Single-bolt Connection

doi:10.3901/JME.2020.13.231

Abstract

Abstract: 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.

Key words: aeroengine, bolted connection, tightening process, tightening speed, pre-tightening force

CLC Number:

TH131

LI Xiaoqiang, MENG Qingkuo, DU Yifan, CHEN Feiyu, WANG Hui, ZHAO Bing. Influence of Tightening Strategy on Pre-tightening Force of Aero-engine Single-bolt Connection[J]. Journal of Mechanical Engineering, 2020, 56(13): 231-241.

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