研究了转子和定子碰摩时振幅的跳跃现象,利用响应相位特征解释了接触诱发‘刚度增加’的机理。当转子与定子之间的间隙足够大时,转子在临界转速达到最大振幅,然后迅速衰减。如果与定子发生接触或碰撞,它们之间的接触将在很宽的速度范围得以维持,即便是转速已经远离临界转速。这一现象也称为‘刚度增加’或‘硬化’(stiffness increase or stiffening)。研究结果表明,形成该现象的机理是由于接触的作用,使得激励与振动响应的相位差保持在小于π/2的范围内。并且振幅跳跃与相位跃迁相伴出现。实验结果也验证了这一结论。
The phase characteristic of a disk rubbing with a ring supported elastically is investigated and used to explain the mechanism of stiffness increase phenomenon. As long as the rubbing is maintained, the averaged phase difference between the disk and the rotating mass on the disk is defi- nitely less than π/2. When the rubbing finishes, the phase difference quickly approaches to 7r. This behavior is inde- pendent of the physics parameters of the rubbing system. The theoretical results are qualitatively verified with experiments.
