Studies And Realization Of Calculation Software For Ship Shafting Torsional Vibration System Based On VB.NET

Ship propulsion shafting is an important part of marine power plant, and shafting vibration is quite influential in the safety and reliability of ship operation. At present, so many units and experts have made generous research on marine shafting vibration, and mastered relatively complete calculation methods, but for the development of ship power plant, many complex propulsion shaftings are coming into being, which makes it more important to further kown well of the mechanism and calculation methods of shafting vibration. Consequently, it put more strict requirements on the calculation software.The paper has researched the basic theory of shafting torsional vibration, and developed a torsional vibration calculation software through mixed programming method within VB.NET and MATLAB on the Visual Studio2008platform based on the present achievements. By making torsional vibration calculations and analysis for complex shaftings, the correctness of software algorithm is tested and verified. Main Contents of this paper are as followings:1) Summarized the calculation model and calculation methods of shafting torsional vibration.Compared the available methods and used analytic method to develop the software.Analyzed the influences that phase difference between two diesel engines, unevenness of cylinder load and propeller excitation made on the shafting torsional vibration.2) Set up the equal model of Shafting torsional vibration with modular method, which improved the calculation efficiency of complex shafting with muiti working conditions. Studied the processing method to customize haomonic coefficiency of gas pressure in the cylinder, and made a comprehensive comparison of shafting torsional vibration stress criteria among the classification societies and Chinese shipbuilding industry standard, both have been integrated into software.3) Studied several key issues about software development, such as interface design、MATLAB interface for VB.NET、graphic processing method of2D and3D pictures and so on. With the help of a third-party control and a customized module, the equal model of shafting torsional vibration could be dragged freely, which made it possible to draw the picture with any branches or any levels.4) Analyzed and compared the merits and demerits between Xml and SQL. Established the frame of shafting components database system.With the concept of modularity to set up equal model of shafting torsional vibration, the data of each component could be save into database, and the data in database could also be inquired and called by software.5) Torsional vibration calculations were made for shafting with single diesel engine, single proprller and gearbox, and shafting with double engine and single propeller. The calculation results were compared with the test results and approved analysis reports, which could show the algorithm is correct. Besides, Took a complex shafting as example, another equal model (changed the order and mass number of main branch as well as subfields) was made for the same working condition, and the calculation result was compared with the original model, which could illustrate that the data processing method is correct.