基于 NURBS 曲面插值的船体曲面重构

摘要

A method for reconstructing the ship hull is presented. The ship hull surface is divided into numbers of panels according to the character curves on the surface. The nets in the wire frame model are dealt with homogeneously to get offset points, on which the character values are added, and the NURBS net is generated. B-spline surfaces with multiple knot points are used to interpolate the nets together with tangential vectors and multiple points, so as to get the panels connected to each other and to form a NURBS surface without gaps. Therefore the complex ship hull surface with a bulb bow, bulb tail, plane side curve, plane bottom curve, partly knuckle curve and transom stern can be constructed by smaller numbers of panels. It provides a favorable NURBS surface in the further design of ship structure, CAM and CFD.%论文提出了一种船体曲面重构方法。首先，用特征线把船体曲面划分为曲面片，便于表达复杂船体曲面和保留船体特征。其次，对船体线框模型的网格均匀化处理，得到型值点的位置，并给它们加上特征，生成NURBS 网格。最后，用带重节点的 B 样条曲面插值带切矢和重点的 NURBS 网格，并进行曲面片拼接，生成无缝隙的 NURBS 曲面。因此，可以用较少的曲面片（几至十几块）重构带有球首、球尾、平边线、平底线、部分折角线和方尾的复杂船体曲面。这给船舶结构设计、CAM 和 CFD 计算提供了良好的船体 NURBS曲面模型。