Analysis Of The Structure Strength For Spud-type Grab Dredger

In recent years, as the areas along Amur River have witnessed rapid economicdevelopment and mounting border trade and cooperation, waterways freight volume hasbeen increasing to a large extent. However, the navigation condition is so severe in theupstream of Amur River, along with plenty of yearly sediment deposition, that watertransport has been impeded and limited to bring economic benefits. Thus it is desperatelynecessary to employ a dredger to dredging the upstream channel in order to clear thewaterway and guarantee the security of navigation.Spud-type grab dredger is an engineering ship, which is widely used and hightechnical. Due to structural features, grab machine is of large working loads, resulting inmuch stress concentration in part of hull structure. Imposed by both wave loads andworking loads, hull structure requires to be checked, focusing on its strength; while as oneof necessarily important components, spud is stressed in a very complicated way, bringingabout high breakage rate along with the problems of fracture and movement of the pile, andso on. Thus structural design and strength check contribute to the security in ship operation.Much analysis needs to be made about the strength of hull and spud structure, so that thestructural strength can resist the joint impacts of working loads and wave loads.The paper presents the study on the spud-type grab dredger navigating Heilongjiangwaters, with the application of MSC.Patran/Nastran software to explore the impacts of grabmachine and spud, the special components of the dredger, on the strength of hull structure.First of all, the global finite element model of the whole ship is constructed, and theboundary and the calculation conditions are examined in accordance with the specificworking condition of the ship; the wave loads in each working condition are to becalculated through three-dimensional hydrodynamic software; in addition, various loads areapplied to the finite element model, and in other words, different external loads areimposed in different working conditions; at last, the finite analysis is made on the structureof the whole ship. In a specific way, the hull and spud in each working condition are to becalculated, and subsequently the optimizing process will be improved by comparison andcalibration of the calculated results of stress and strain.