流线型列车头部外形设计方法

基于流线型的列车头部外形由三维空间自由曲面构成,提出采用NURBS曲线设计外形型线和用三维NURBS曲面描述复杂三维曲面的车头外形设计方法。按照流线型列车头部外形的设计要求,首先生成基本控制型线,根据需要自动生成中间控制型线;对一些型线进行空间动态修改,使所有控制型线构成空间网状结构;将这些控制型线在空间的交点处断开,形成首尾相连的NURBS曲线段;自动将首尾相连的NURBS曲线段连接形成外形曲面片,并保证曲面片在空间相切;最后对外形曲面进行光顺性检查,得到最终的外形曲面。运用NURBS曲线曲面的数学模型,在AutoCAD的ARX及I-deas的Open I-deas开发平台上,开发了流线型列车头部外形设计模块,实现了按照人们的意志,自由、快速地设计复杂的空间三维曲面流线型列车外形。

Shape Design Method for Streamlined Train Head

The shape of streamlined train head is made of the 3-dimensional space free form surface,whose shape outline curve uses NURBS curve and complex shape surface uses 3-D NURBS surface.Firstly the basic controlling outline curves of shape were built and then the assistant controlling outline curves were created according to the shape design need of streamlined train head.The whole controlling outline curves were made up of space grid structure after some modifications.The whole curves were broken at the point of space intersection and the NURBS curves were joined from beginning to end.They were connected to form shape surface which were ensured to be tangent in the space.Lastly the light-smooth check of shape surface were carried through,then the final shape of streamlined train head was gained.The shape design method of streamlined train head was realized on the ARX of AutoCAD and the Open I-deas of I-deas software flat roof on the Non Uniform Rational B Spline curve and surface mathematic model,the shape of streamlined train head was designed freely and quickly according to people's will.