Study On The Structural Strength And The Dynamic Behavior Of Large Floating Crane's Hull Structure

Thanks to the economic development and the demand of offshore structure, large floating crane's demand is increasing. Hull structure of large floating crane is the support platform of floating crane, especially for the hoisting machinery. The hoisting machinery lifts thousands of cargos within short time, which makes the displacements of the floating crane increase suddenly. When the revolving floating crane lifts cargos, the center of gravity changes rapidly. Compared to above characters, the paper studies the structural strength and the dynamic behavior of large floating crane's hull structure.Firstly, the paper declares the methods for the study on hull structural strength and dynamic behavior. Secondly, this paper studies the 7500-t"Lan Jing"floating crane's working characters.First of all, middle section of the crane's hull is designed according to its working conditions. Longitudinal strength is also checked based on CCS Rules. Further, the FEM model of three cargo holds and stern of the floating crane are established, and structural assessment results of typical load cases are carried out.Secondly, the added water mass is calculated with Lewis theory and the virtual mass method which is based on boundary element method theory.Thirdly, the paper studies the natural vibration and mode shape of floating crane with the one-dimensional beam FEM method,3D FEM method and mixture model methods.Fourthly, the paper presents the transient responses of floating crane under the vibration response by suddenly lifting cargos, then compared to the results of static state.In the end, the paper assesses the structural strength and the dynamic behavior of the hull structure based on above analysis.The methods and processes used in the paper are of value for further study on structural strength and dynamic behavior of similar floating crane's hull structures.