Objectives In order to formulate an optimization plan for the torsional vibration parameters of a marine diesel generator shaft system, it is necessary to analyze the transient torsional vibration characteristics of the diesel generator under short-circuit impact.
Methods The shafting transient torsional vibration character-istics of a 20-cylinder V-type diesel generator set under short-circuit impact are analyzed by the Newmark method, and the effects of different shafting parameters on its shafting transient torsional vibration characteristics under short-circuit conditions are discussed. A new selection scheme of shock absorber stiffness and coupling stiffness is then determined.
Results The calculation results show that the shafting torsional vibration characteristics deteriorate significantly when short-circuit impact occurs. After optimization (the stiffness of the torsional shock absorber and coupling are optimized to 90% and 70% of the original value respectively), the instantaneous maximum torque of the motor shaft, instantaneous maximum torque of the coupling and instantaneous maximum stress of each shaft section of the crankshaft under short-circuit impact conditions are reduced by 13.43%, 10.51% and 5.29% respectively.
Conclusions The proposed optimized design scheme can effectively reduce the transient torsional vibration level of shafting systems. The results of this study can provide useful references for the vibration and noise reduction design of diesel generator sets.
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