Papers by Keyword: Transient Resonance

Abstract: The dynamics of a two-degree-of-freedom (2-DOF) nonlinear system, consisting of a grounded linear coupled to an attachment by means of an essentially nonlinear stiffness, is studied. The essential nonlinearity of the attachment enable it to resonate with any of the linearized modes of the substructure leading to energy pumping phenomena, irreversible transfer of energy from the substructure to the attachment. We then study analytically the periodic orbits of the system using a complexification/averaging technique in order to determine the frequency contents of the fundamental branches of solutions, and to understand the types of oscillation performed by the system at different regimes of the motion. The results of numerical analysis show complex dynamic structure of the system.

Abstract: Traction drive elevator installations employ ropes of variable length as a mean of car and counterweight suspension. The inertial and elastic characteristics of elevator suspension systems depend on the rope construction and vary slowly during the elevator travel. The system suffers from vibrations caused by various sources of excitation. This paper presents the analysis of the dynamic response of the suspension system employing traditional steel wire ropes as well as ropes constructed of aramid fibers. The equations describing the lateral response of the system subjected to a boundary periodic excitation are solved numerically. The results show that the entire rope is subjected to repetitive low frequency transient resonances. Consequently, the structural integrity of the suspension ropes is compromised. The issue of active vibration control and the feasibility of the integration of shape memory alloy elements within the suspension rope design are discussed.