Nonlinear dynamic characteristics of a dual flexible rotor system with rub-impact supported by long journal bearings
This study develops a mechanical model for a complex rotor system supported by long bearings,focusing on a double-disc rotor system with asymmetric nonlinear spring-damping cou-pling.First,nonlinear forces,including the lubricating oil-film force and the rub impact force due to rotor-stator contact,are calculated.The interaction between the bearings at both ends and the base is modeled as a nonlinear elastic damping coupling.Second,employing a multi-objective,multi-parameter collaborative coupled simulation analysis and the variable step size fourth-order Runge-Kutta method for numerical computation,the study investigates the modal types,distribution areas,and bifurcation characteristics of periodic rub-impact vibrations in a long-bearing double-disc rotor system.Finally,the research reveals the relationship between the system's dynamical properties and its model parameters.The results show that the rotor system exhibits typical nonsmooth characteristics as the stator stiffness ratio or speed ratio in-creases.The system frequently experiences the coexistence of multiple cycle types,and its non-linear vibration characteristics display complexity and diversity when parameters such as stator stiffness ratio,gap threshold,and speed ratio are varied in a coupled manner.As the eccentric-ity ratio increases,both the maximum rub-impact force and the rub-impact duty cycle within the system rise.Changes in the system's friction coefficient have a relatively minor impact on the mode types,distribution patterns,maximum rub-impact forces,and duty cycle values of the system's periodic vibrations.Subharmonic periodic vibrations and chaotic behaviors,among other complex periodic rub-impact vibrations,are observed to persist as the speed ratio increases.
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维普
