| Improving the noise masking performance of naval vessels has great significance for enhance its own combat and survival ability. Power equipment is the main noise sources of ship, isolator which is widely used to prevent the vibration transmitting from power equipment to raft foundation or ship body, greatly reduces radiated noise of ship body, so the isolator improves the quiet and concealment of ship; but on the other hand, isolator also remarkably increases the support flexility of rotor, causes large coupling dynamic misalignment, results in complex harmonic and high frequency vibration and decreases stability and reliability of ship power equipment. Therefore, dynamic coupling effect of coupling and isolator has significant impact on dynamic behaviors of ship power equipment. In this paper, for rotor-coupling-bearing-isolator system in ship power equipment, the dynamics and stability of this system and its coupling components is studied theoretically and experimentally, with purposes of providing effective methods and valuable references for coupling matching design in large rotating machinery.(1) Considering the static, dynamic misalignment and conditions changing of rotor system, dynamic meshing force model of gear/spline coupling is derived according to classic deformation theory of gear tooth. The change rules of coupling meshing force with structural parameters and system parameters is obtained by simulation, and the correction of this model is validated with linearized mesh stiffness. Research results provide model basic for coupling optimal design and dynamics study of rotor-coupling-bearing system.(2) Based on the static compression test, generalized Hooke's law and strain energy density, static stiffness model of rubber isolator which reflects rubber hyperelastic properties is derived; and isolator dynamic stiffness model with considering static stiffness, excitation amplitude and excitation frequency is also established; Dynamics simulation and experiment of SDOF rubber-isolator system is employed to verify the accuracy and effectiveness of the dynamic stiffness model in describing the dynamics characteristics of rubber isolator.(3) Dynamic stability criteria of rotor-coupling-bearing system is proposed, which provides useful stability criterion for dynamic design, testing and operation of large rotating machinery. With theoretical analysis, numerical simulation and experimental test, the influences of coupling type, modeling manner and misalignment on dynamics and stability of rotor-bearing system is studied. The instabilities of rotor-bearing system connected by rigid and flexible coupling are caused by oil whip, however, instability of rotor-gear coupling-bearing system is caused by combined effect of oil whip and gear coupling self-oscillation, and misalignment of gear coupling changes the stability of the system significantly.(4) Complete coupled dynamic model of rotor-coupling-bearing-isolator (foundation) system is established. The dynamics of rotor-coupling-bearing system and rotor-coupling-bearing-isolator system is comparatively studied with numerical simulation and experiment, vibration isolation effect of isolation is validated by comparing the vibration difference levels between rotor and foundation of two systems. Research results which verified the accuracy of dynamic stiffness model of rubber isolator and the system dynamic model improve and enrich research system of noise and vibration reduction of ship power equipment.(5) Considering the characteristic that dynamic misalignment of actual ship power equipment cannot be tested, dynamic misalignment in rotating machinery is abstracted and studied for the first time, and calculation method of coupling dynamic misalignment is proposed. Complete matching design scheme of coupling in large rotating machinery including coupling style selection, structural parameters design, misalignment compensation capability is formed. The results show that dynamic misalignment in two ends of coupling is biggest near critical speeds of the rotor-couplings-bearing (isolator) system, and the emergence of isolator significantly increased dynamic misalignment volume in non-critical speed region.(6) The sources, characteristics and malfunctions coupling mechanism of three kinds of malfunctions of imbalance, misalignment and instability in rotor-coupling-bearing-isolator system are analyzed. Malfunctions coupling leads by dynamic coupling effect of gear coupling and rubber isolator which causes complex system vibration, reduces the stability of the whole system. Combining theoretical and experimental research results, some guidance advices of alignment control during installation and actualizing methods of vibration monitoring and fault diagnosis during operation of ship power equipment is provided.
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