Study On Three-Dimensional Uniformity Checking And Fairing Modification Of Ship Form

Ship form is the foundation of the performance calculation, general arrangement, structure design and ship hull lofting. Ship form has a great influence on the performance, using and construction of the ship. Therefore, the accuracy and fairing of the ship form play an important role in the ship design.However, because of the errors or modifications of the local fairing, the ship form will not be three-dimensional uniform. It will lead to the inaccuracy of the ship form, and bring troubles for lofting so that effecting the accuracy and efficiency of shipbuilding. So the ship form must be checked to improve its accuracy. At the same time, the fairness of the hull surface must be ensured for the ship having perfect resistance performance and outer plate manufacturability,. Determining the fairness of curves and surfaces, on the one hand, can rely on the experience of designers. On the other hand, the fairing problem will be transformed into a mathematical problem. The mathematical method will be used to fair the ship form in this paper.There are some methods to fair curves, but the method of three-dimensional uniformity check of ship form is infrequent. Therefore, the study on three-dimensional uniformity checking, modification and fairing is going on, and the program is developed with ObjectARX. The contents are as follows.(1) Ship form has a great influence during the ship, design as well as the accuracy and fairing are significant to the ship form.(2) Check the nonuniform points in three directions, and deeply research modification method of the ship form. The principle of modification is considering the body lines at first. Secondly, check the other views about the situation of fairness. Then, determine the line that need to be modified.(3) Introduce the concept of curvature. Determine the inflexion points by curvature. Bad points selection is adopted to fair the ship form.(4) Based on AutoCAD2007, on the Visual Studio2005programming environment, ObjectARX development tool is adopted to develop software and achieve the functions above, including nonuniform points check, ship form modification, finding "bad points", and ship form fairing. It is hoped that this software provide reference for the future software development and application.