Dynamics and Control of Elevators with Large Gaps and Rubber Dampers

Abstract

Structural dynamic responses of elevator counterweight systems with discontinuous connectivity (a large gap) between the counterweights and their frame are evaluated using the finite element techniques. External base excitation results in dynamic contacts between the weights and frames. A contact element with nonlinear stiffness and damping is developed to simulate the dynamic contact. To prevent the dynamic contacts and to improve the structural dynamic responses, rubber dampers modeled by a rubber finite element are introduced between the frame and the weights. The analyses show that introducing a large separation between the counterweights and the frame eliminates the dynamic contact at small amplitude oscillation; however, the contact load increases if the base motion exceeds the separation. The implementation of rubber damping can reduce the load by 84% as compared with that of current design practice. A design equation and a proposed installation of the rubber damper are also proposed and illustrated.