Research On Fast Modeling Method Of Hull Structure Based On NX Platform

The 3D modeling of hull structure is a very important step for ship design and production.Not only the CAD model can guide the actual production process of shipbuilding,but also it is the input data for finite element analysis and the standard ship calculation.Through the analysis and calculation,the defects of original design can be found and the initial design scheme should be modified to achieve a more optimized version.Because of the complexity of hull structure,there are plenty of components.Usually a lot of repetitive work is involved in the process of modeling.Now the existing software such as are weak in parametric modeling function or not convenient for users.What's more,batch modeling function is not supported.Manual operation occupies a large proportion in these software.As a result,the efficiency of ship modeling is low.It is necessary to study the 3D modeling methods of hull structure to design a CAD system with high automation and fast modeling speed.This paper is based on the cooperative project of China Classification Society called Compass which is a new generation of marine engineering calculation software system.By making use of NX secondary development technology,the research takes the structural characteristics of each ship component into consideration and tries to find out suitable and practical methods for the modeling of ship structure.In order to meet the requirements of different kinds of components,this paper adopts the system design idea which combines general modeling with parametric modeling.In the general modeling module,the NX custom feature technology is used to describe the components and all the panels are characterized and managed by a unified feature.In the parametric modeling module,3 methods of parametric modeling based on the NX sketch are proposed.The parametric method based on feature replacement of sketch template is aimed at components that are attached to others,can't be fully parameterized and are difficult for batch modeling.The parametric method based on customized process and automatic drawing of sketch is for the rapid modeling of the components with complex structure and modeling steps,resulting in the time reduction of manual operation.The parametric method based on standard sketch template is for a variety of frequently-used standard components,decreasing the time of repainting the outline of a component.Finally,by carrying out the real ship modeling process and comparing the proposed modeling methods with the traditional ones,the CAD modeling system is proved to be efficient and practical.