In view of the lack of evaluation methods for acceleration ability of domestic trade container ships in wind and waves,starting from the characteristics of low-speed and fat-hull-typed container ships,combining with the hydrodynamic charac-teristics of propellers and the analysis of ship's acceleration in wind and waves,the ship's propulsion conditions in extreme wind and waves was simplified to analyze several key factors related to the ship's acceleration capacity.Considering the conditions for the main engine to quickly cross the barred speed range,the evaluation of the ship's acceleration ability was set forth.Taking the torque margin at the upper limit of the barred speed range under the ship's bollard state as the first level criterion,and taking the torque margin at the service speed of the propeller under the high sea state as the second level criterion,the ship's acceleration ability in the wind and waves can be valued during the design stage.The calculation process was given,which had been verified by a real ship calculation example.
Poor heave performance is the bottleneck that restricts the wide application of cylindrical FPSO in offshore oil and gas development.The extended cylinder and damping structure were added at the bottom of the platform to improve the hydrody-namic performance of the cylindrical FPSO,so as to reduce its heave amplitude to meet the requirements of dry production equip-ment.Based on the 3D potential flow theory,the hydrodynamic analysis model of cylindrical FPSO with motion suppression de-vice was established to analyze the influence of different heights,widths,cross-sectional shapes and sea valve of the motion sup-pression system on the hydrodynamic performance.Comparing the response transfer functions of motion amplitude with different motion suppression equipment,it was found that the hydrodynamic performance of the cylindrical FPSO can be improved by open-ing damping holes to connect the water inside the motion suppression device to the sea;properly increasing the height and width of the damping structure is conducive to increasing the natural period of heave motion,so as to avoid the wave period of 100-yr scenario in the South China sea,which will contribute to reducing the motion of cylindrical FPSO.
In view of the lack of uniform standards during the FE modeling,leading to inconvenience of generating,manage-ment,merging and data exchange with FEM,a complete set of standards of ship hull FEM was proposed,based on the industry rules and practical experience.The method of model expression was specified,and the standard definitions of material and prop-erty were introduced in detail especially.In order to generate and manage the standard FE model quickly,a standardization tool was developed based on FEMAP.The customized data interface was developed for several common software.The practical appli-cation results showed that the standard is scientific and reasonable,and it has good practicability.Related tools would be a great help to modeling efficiency.
In view of the requirements of designing and installing the waste gas SCR treatment equipment and system on ships,taking the loading style of SCR system of 85 000 DWT bulk carrier as an example,the types and characteristics of marine waste gas treatment technology,as well as the requirements and actual components of SCR technology were analyzed.The practi-cal application and workflow analysis of marine waste gas SCR treatment system showed that in the practical application of SCR waste gas treatment technology in marine systems,equipment installation,system pipeline length and direction,exhaust tempera-ture and urea solution injection volume control will affect the actual treatment effect of NOxin waste gas,and the system design should follow certain design principles,layout methods and pipeline design requirements.
The foremast with crane supporting for container ship is subjected to the load of crane on the crane support be-cause of the ship tilting,motion and wind and its structural strength is the focus of attention.The D-type foremast of a container ship was taken as an example,and the structural strength of the foremast with crane supporting of this ship was assessed by finite element method.The numerical results showed that structural stress concentration in the bracket toe has been reduced by adjus-ting the design of the bracket,so as to meet the rule requirement.
