Optimal Structure Designing Of The Offshore Deck Crane Jib Based On Genetic Lgorithm

Offshore Deck Crane is a kind of ship crane broadly used in maritime lifting operations. With the rapid development of the offshore oil exploitation, super large deck cranes are needed to build offshore oil drilling platform. In order to realize the cargo fast loading and unloading due to the trend of upsizing on container ships, various cranes are moving to high efficiency and huge-size. All of these cause the size of the crane, its own weight and loads increasing. For Offshore Deck Crane, jib system is the main bearing components, which transfers lifting weightiness to slewing platform. It stands all outside loads and must meet requirement of the strength, stiffness and stability. The jib has significant impact on the whole machine's performance, such as its own weight and stability. Cranes lifting capacity becomes heavier, which increases the weight of the jib structure and consumes a lot of steel. The quality of the jib structure design will affects the machine performance directly. It has significant economic benefit and social benefit to reduce the weight of the crane under the condition of satisfying relevant design standards. Therefore, it is essential to analysis and optimize the jib structure of the Offshore Deck Crane.In this paper, all researches are based on the project of design 300 ton Offshore Deck Crane. The paper establishes a set of dedicated analysis system, using ANSYS parametric design language APDL, realizes parametric modeling, structural static analysis and modal analysis, obtaines the stress, strain results, the structure of the natural frequencies and the corresponding vibration mode shape. After the finite element analysis, some unreasonable parts are found in the structure. Seasonable adjustment is necessary. This paper establishes the optimizing mathematic model of the jib system based on optimization design theory, determining that optimal functions is minimum weight of the jib structure. Chooses 12 design parameters as variables and sets up constraint condition by intensity, stiff and stability of structural. Optimizes jib structure by Genetic Algorithm Toolbox, getting optimal solutions for the constrained optimization problem. The optimal results are rounded off to the nearest millimetre to get the final optimal results. Then assess the final results through jib structure analysis system.The Offshore Deck Crane jib structural could be scientific, economic and social by optimizing design under the condition of meeting requirement of the relative criteria. It is expected that the method of optimization design combining the genetic algorithm will attracte more and more concern and be widely used in many industrial fields.