电梯系统共振失效的灵敏度研究

以曳引式电梯为研究对象,考虑电梯曳引绳刚度具有时变特性,对电梯系统建立了8自由度耦合振动的动力学模型。在对系统进行模态分析的基础之上,以影响系统模态频率的动力参数作为随机变量,结合DOE试验方法与神经网络技术,得出系统随机变量与系统模态响应之间的显性函数关系式。依据动态结构系统的固有频率与激振频率差的的关系准则,定义了系统共振的失效模式,并对系统的随机变量进行了可靠性灵敏度分析。研究表明,绳头侧刚度和曳引机支撑刚度对频率共振影响最为明显,因此,在电梯系统设计中可以通过修改该动力参数达到有效降低共振的风险。同时,在实际工作中应该严格关注和监视该动力参数的变化,避免发生共振。

Resonance failure sensitivity for elevator system

Taking the traction type elevator as the research object, and considering the time-varying characteristics of traction rope stiffness when the elevator is in normal working, the eight degrees of freedom dynamic model of coupled vibration is established for studying the vertical vibration characteristics of the elevator system and the sensitivity of natural frequency dynamic parameters impacting on the elevator system. On the basis of modal analysis to the elevator system, dynamic parameters impacting on the system modal frequency are selected as random variables. Combining design of experiment (DOE) test method and artificial neural network (ANN) technology, the explicit function was obtained between each random parameter and modal response of elevator system. The absolute value of the deviation between natural frequency of the dynamic structure system and excitation frequency should not in excess of allowance, so the failure mode of system resonance was defined, and the reliability sensitivity of the elevator system also was studied. The result reveals that the termination stiffness of the traction rope and the isolation pad of traction machine are prominent factors for system resonance. In practice, the risk of resonance will be able to mitigate effectively by modifying these parameters. Simultaneously, the changes of these dynamics parameters should be strictly monitored against to preventing resonance in working process.