Analysis of oscillations (vibration) of structural elements of lifting mechanisms and machines

Abstract

Cargo movement by hoisting mechanisms and machines used in urban construction, such as overhead cranes (OC) with non-rigid rope suspensions of the load causes pendulum vibrations of the load, in which there is an uncontrollable component. The oscillations significantly increase the cycle time of such OCs, reduce productivity and safety. There is a growing danger of collision of the load with objects present in the movement zone, and damage/destruction of the load, other objects and the OC itself is probable. In this regard, it is advisable to completely suppress uncontrolled components of pendulum oscillations of the load both during its movement and when the load reaches the target point. This is especially important when moving dangerous cargoes: containers with liquid materials (such as resin), flammable liquids, etc.

During the operation of OC and other types of construction/cargo lifting cranes due to the swinging of the load on the rope there are significant dynamic loads. In this paper we analyze the regularities of the process of load oscillations on the basis of a two-mass model, taking into account the influence of initial conditions on the possible values of dynamic loads, as well as the possibility of optimizing (minimizing) these loads.

 The review of available reference and normative materials determining the normative values of dynamic coefficients is given. The results obtained in the paper can be further used for dynamic calculations, their improvement and refinement, for design and engineering development of finite element models of cantilever booms with loads on the rope and without rope during acceleration/deceleration in the process of boom rotation to substantiate the dynamic coefficients of specific designs of OC and urban construction cranes of other types.