Load calculation and strength analysis of floating garbage cleaning equipment

In order to alleviate the problem that there is increasingly floating garbage pollution on the sea, this paper proposes a new design of floating garbage cleaning equipment. This equipment is a slender structure, and whether its structural strength can meet the design requirements requires special attention. In order to ensure the rationality and safety of the design, load calculation and strength analysis are carried out based on the design wave method. The calculation results show that the longitudinal torque load of this equipment is the largest, which is 2.5 times of the second largest vertical bending moment. At the same time, there are three large stress areas in the floating structure, which are the connection between the pontoon and the connecting buntons, the connecting buntons intersecting with the Y axis and the pontoons on both sides. For the abovementioned high-stress areas, a structural strengthening plan is proposed. After the improvement, the stress in the high-stress areas of the structure is significantly reduced, with a maximum reduction of 52%. The strength of the improved structure meets the design requirements. The research results of this paper can provide relevant references for the development of floating garbage cleaning equipment in the future.

Improvement of Wave Loads Estimation From Spatial Pressure Distribution on Ship Hull

In modern shipbuilding industry, merchant ships tend to increase in size. Accurate prediction of the vertical bending moment in large-maplitude waves has become important for structural design. For establishment of an accurate estimation method, more detailed local hydrodynamic quantities such as the spatial pressure distribution on the whole ship hull surface should be checked. For that purpose, the experiment has been conducted by means of Fiber Bragg Grating (FBG) sensing technology. Using the measured local pressure distribution by only sticking the FBG pressure sensors onto the hull surface, we can evaluate the wave loads; which may lead to establishment of a new evaluation method for the wave loads without using a segmented model. We confirm favorable agreement of the pressure distribution between measurement and computation by Rankine Panel Method (RPM). Furthermore, the vertical bending moment computed at some transverse sections shows favorable agreement between measured and computed results.

A Method for Designing the Backbone for the Segmented Model of an Ultra-Large Container Carrier

The segmented model test is often used to study the wave load characteristics of large ships as it can account for the hydroealstic effect. The vertical bending moment (VBM) is of crucial importance in ensuring the safety of ocean-going vessels in rough seas, and there exists in the literature a large number of experimental studies of the VBM. For ships with large openings in the deck, for instance, container ships, the lateral wave loads, such as horizontal bending moment (HBM) and torsional moment (TM) in quartering seas, are as important as VBM. There are, however, few studies on the measurement of the coupled horizontal-torsional vibrations of such ships in model tests. In the paper, a method is proposed for designing flexible backbone models that satisfy the similarities of vertical and horizontal bending stiffness as well as the torsional stiffness, and the measurement of the wave load components is also described. In order to meet the similarity of the hull girder stiffness, the backbone cross-section of a complex form is designed. Finite element method (FEM) is used to calculate the natural frequencies and mode shapes of the segmented model. Measurement of the vertical bending moment, horizontal bending moment and torsional moment are calibrated by applying various combinations of loads.

Effect of Special Outermost Module Designs on the Hydrodynamic Responses of a Modular Multi-Purpose Floating Structure System

The present work investigates the effect of different outermost module designs on the hydrodynamic responses of a modular multi-purpose floating structure (MMFS) system. The MMFS system is initially designed for a mild sea zone. As the entire system consists of more than 20 bodies, a simplified system with seven interconnected standardized modules is proposed for numerical and experimental study. In this simplified system, each module is assumed as a rigid body. Both hydrodynamic interactions and mechanical coupling among modules are taken into consideration in the time-domain numerical analysis. The structural deformation of the MMFS system mainly occurs in the connectors among adjacent modules. The maximum deformation appears at the connectors between outermost modules with the internal modules. To reduce the deformation and improve the concept, two special design, outermost module of deeper draft and outermost module with additional heave plate are proposed and investigated for the MMFS system. The numerical results indicate that the two proposed designs for the outermost module can significantly reduce the hydrodynamic responses of the MMFS system, especially the motion of the outermost module and the vertical bending moment on the connector. The extreme responses of the MMFS system with different outermost module designs are also studied and compared.

KEKUATAN BATAS LAMBUNG KAPAL DALAM MENAHAN MOMEN LENTUR VERTIKAL

On the life, the ship will constantly get the structural load caused by the external load of the internal waves and loads of the ship's load and the structure itself which then reaches the ultimate strength of the structure. This study aims to determine the strength of the boundary of the hull due to the vertical bending moment so that the ship structure can be guaranteed security. The analysis was done by using finite element method (FEM) by modeling the structure of the tanker section modified based on the shape of the girder box so that a simpler model is obtained. This calculation is done by using ANSYS 17 software. The calculation of vessel structure is simulated based on two existing models namely girder box model and modified tanker model. In the girder box model, ultimate strength is obtained at 6,311 x 108 Nmm for hogging conditions and -6.311 x 108 Nmm for sagging conditions. While on the tanker model, the ultimate strength obtained is -8.99 x 1012 Nmm for sagging conditions and 1.0277 x 1013 Nmm for hogging conditions.