Dynamic analysis of the rope-sheave system of polar crane for nuclear power plant

A systematic method for analyzing the dynamic of the rope-sheave system of polar crane for nuclear power plant is proposed taking physical structure of the system into account based on the virtual power principle in this paper. The dynamical equations of the spatial ropes are established by spline interpolation based on the spatial description parameters, which could be applied to the rope with variable length. For sheaves of different types, the corresponding essential parameters and the virtual power equations are given. Properties and formulations of the variables involved in these equations are studied in detail. In order to improve the solving efficiency, the high-frequency items are filtered out by replacing the instant strain by time- average strain in integral and the degree of freedoms (DOFs) of the spatial ropes are condensed to the boundary nodes of the ropes. Hence, the total virtual power equation in terms of the sheaves’ parameters is obtained. Two numerical examples, including lowering the load and hoisting the load for different types of rope-sheave systems, are given to verify the rationality and feasibility of the method.