Research On Shin Hull Line Fairing In Three Directions Based On CATIA

In order to possesses specific marine performances,a ship' hull surface is always a complicated surface.And in order to ensure the streamline shape of the hull surface,it is necessary to ensure the smoothness in three directions of the hull surface.The hull surface is described by the hull line,so smooth hull line must be obtained first to get the smooth hull surface.The hull line fairing in three directions means that hull lines in the three projection view all meet the requirements of smooth and consistency of the offset value.The HD-SHM software,developed by Hudong Zhonghua Shipbuilding Co.Ltd.,is one of the products of mathematical lofting replacing manual lofting.The software has a series of functions,including line generation and interactive smoothing in three directions.And it has been applied in small and medium-sized shipyards and has a fairly large market share.However,in recent years,with the continuous improvement of 3D design requirements,the application of CATIA software in the field of domestic shipbuilding is more and more extensive.The whole design process,business process and technology system of ship industry are gradually transferred to the CATIA software platform.Through literature search research and ship enterprise survey,it is obtained that,there is almost no literature on the fairing of hull lines by using CATIA software,and ship enterprises use HD-SHM software to complete hull line fairing work first,then import the data after fairing into the CATIA platform to carry out follow-up work.Therefore,in order to meet the trend of unified ship design platform in domestic,unify the data sources and avoid the tedious data exchange between different platforms,this paper took the initial value table of a 11000 DWT bulk carrier as the initial data,combined with the general principles and methods of hull line fairing,and referring to the fairing operation process of HD-SHM software.Then the hull line fairing work is carried out on the CATIA software platform.Firstly,the general principles and methods of ship hull is studied,including fairing principle of a single line,fairing criteria,modification of hull line which is not smooth,fairing examination of hull lines in three directions and so on.At the same time,taking HD-SHM software as an example,analyzing the process of profile fairing,which can lay the theoretical and practical foundation for carrying out hull line fairing work in three directions based on CATIA software platform.Secondly,combining the analyzing functions of curve and surface of CATIA with hull line fairing process,based on which,the idea of pushing hull line fairing process from 2D to 3D is applied.And,the fairing method based on curvature bar is proposed,which can realize the function of real-time dynamic identification and adjustment.It makes the hull line fairing process more intuitive and efficient.And,fairing methods and process based on CATIA are concluded.Thirdly,based on CATIA secondary development technology,some useful automatic programs were developed,which can be embedded into the software platform,like batch import of offset value points and automatic discrimination of hull line fairing and so on.The small function programs can efficiently optimize the hull line fairing process.In this paper,the process of hull line fairing is pushed from two-dimensional to three-dimensional,which saves the consideration of the projection consistency of hull line fairing in three directions of the traditional software platform.And,a more intuitive fairing method based on curvature bar is applied based on CATIA.With the help of CATIA secondary development technology and some special functions of CATIA,the fairing process of hull line is completed on CATIA software platform.The results show that,through CATIA secondary development technology,CATIA software can be used to carry on ship hull line fairing in three directions,and it is more efficient to complete ship hull line fairing work on this platform.