Torsional Vibration Response Characteristics and Structural Optimization of Compressor Shaft System Considering the Effect of Variable Inertia

Due to the variable inertia of the crank linkage mechanism, the shaft system will experience fluctuations in the natural frequency, which will increase the probability of coincidence with the motor excitation frequency, resulting in torsional vibration, thus reducing the reliability of the compressor. The on-site vibration of a compressor shaft system shows that the working speed of the shaft system falls within the range of the 1st quasi-resonant speed range, triggering the phenomenon of shaft torsional vibration. In this article, the lumped-mass design of the shaft system is established. The resonant speed range of the shaft system is determined by combining the numerical analysis and the vibration test method, and the law of variation of the torsion angle of the shaft system is controlled using the modal superposition method of variable parameters. Finally, the response surface method and the NSGA-II algorithm were used to optimize the design of the shaft system structure. The results show that the lower limit of the 1st natural frequency of the optimized shaft system is increased by 9.2% and the maximum torsion angle is reduced by 32.1%, which effectively avoids the torsional vibration phenomenon of the shaft system.