Modeling and Finite Element Analysis of the Hydraulic Buffer in Elevator Systems

摘要

Hydraulic buffers are safety protection devices for elevators beyond the limit position. The hydraulic buffer prevents the downward motion of the elevator, which impacts it, by absorbing the kinetic energy of the elevator carriage. A simplified modeling method has been proposed in this article for the finite element (FE) analysis in the case of elevator falling to the pit bottom. According to the structural properties and dynamic mechanism of the hydraulic buffer, a mathematical model has been established to represent the buffering process. Based on a nonlinear relationship between the pressure and velocity, which is simulated via MATLAB, a simplified model for the hydraulic buffer is established using connector element in ABAQUS. The curves of the acceleration and velocity as a function of time during buffering are obtained by using a simplified FE impact model to analyze the elevator falling to the pit bottom. Finally, the whole FE analysis has been conducted for the elevator falling to the pit bottom by imposing the loading in the form of the acceleration-time curve. The results obtained in the article show that: firstly, the acceleration-time and velocity-time curves obtained by the simplified FE impact model match well with those obtained by the mathematical model and experimental tests; secondly, the bottom beam of the elevator carriage absorbs the kinetic energy and incurs the plastic deformation during the impacting with the hydraulic buffer. The method proposed in the article is very useful in applications of FE analysis to large elevators.