Ship Structure Analysis And Optimization Based On Finite Element Method

The purpose of this paper is searching for a working flow of structure design: quantitative analysis the security and rationality of ship structure by strength measure, and father optimal designing structure.The frame of content divide into two parts: analysis and optimization, the former includes static analysis and working simulation, the other includes ANSYS optimization and second programming.The works of this paper can be concluded as follows:1) The structure strength of salvage lifting twin hull and floating dock in kinds of static states is analyzed, the safety of structure is ensured.2) The method of real time working process simulation calculation on a floating dock is studied during the whole process when the ship section is being moved on to. Firstly 3-D finite elements model of floating dock is constructed. Secondly calculation of counteraction forces on moving airbags are carried out according to force and moment equations. Afterwards ballast condition of every ballast tank of the dock are calculated real-timely for every loading step by applying "Powell" and "SUMT" methods. Then frame structure of working process is constructed with APDL's command flow method and total 31 loading steps are applied to the process simulation of the dock. Finally the FE structure model's strain and stress state under every loading step and the structure's analysis results for any wanted node of the dock related to time course can be made out.3) Optimal methods of a stiffened plate under typical situations are researched about. By utilizing the ANSYS optimal module and secondly developing program, reasonable results are gained.4) The meanings of "ground structure method" and "homogenization method" is absorbed, a new approach, which is "forming topology by the route of force" and "gradually deleting and polarizing the finite elements", is given. The main obstacle lies in secondly developing the function of topology optimization based on ANSYS. The types of elements for topology optimization are widen and the problem could be solved not only for continuum structure but also for truss structure. Then the typical examples of a continuum structure and a truss structureare verified by corresponding program. Lastly anticipated result is obtained by applying to a gross panel structure of a ship.