Dynamic Analysis of a Quay Crane Using Lumped Parameter Models

The objective of this research activity is to evaluate the extent to which models with lumped parameters might be appropriate for the development of lifting devices. The models we used have only one or two degrees of freedom, but the parameters of the crane were derived by a FEM analysis of its structure, while the viscoelastic parameters of the ropes took into account their time-varying behavior. The results showed that it is useful to consider the length of the ropes in order to calculate more accurately the dynamics of the crane, since the stiffness and the damping change during the load movement. According to the results, higher stress values were also obtained using the model with one degree of freedom for the ropes. This implies that the model can be useful for rope selection as it ensures a conservative estimate of their coefficient of safety. In the case of the two-degree-of-freedom model, the same is true for the structure.