流线型列车头部结构设计方法

为使列车头部结构完全吻合流线型外形,提出沿列车的纵剖面、横剖面和水平面3个方向布置平面曲梁,形成空间网格状结构形式的设计方法。通过NURBS曲面分割离散与迭代相结合的方法得到平面曲梁的主棱边;以主棱边为基础,采用三维实体几何造型技术生成平面曲梁的三维实体;采用形体的Brep法读取平面曲梁三维实体图的数据面,利用坐标轴变换,创建CAD平面图。运用NURBS曲面的求交理论及三维实体几何造型技术,在AutoCAD的ARX、I-deas的Open I-deas开发平台上开发了流线型列车头部结构设计模块;应用NURBS曲线的线段拟合理论拟合平面曲梁的轮廓曲线,并根据数控加工设备的参数,在AutoCAD的ARX开发平台上开发了流线型列车头部平面曲梁数控加工模块,在不同的数控加工设备上实现平面曲梁的数控加工。

Structure Design Method of Streamlined Train Head

The space grid structure of the head structure of train tallied with streamlined shape completely was formed, whose bend sheet-beam were located along the three directions-vertical, transverse and horizontal section plane. The 3-dimensional geometric modeling technique was adopted to build the 3-D solid modeling of the bend sheet-beam based on the main edge which was calculated in this way of segmentation connected with intersection of NURBS surface. The CAD plane drawing of the bend sheet-beam was created through coordinate transform after reading the data face of its solid drawing adopted the frame Breplaw. The structure design module of streamlined train head was carried out on the ARX of AutoCAD and the Open I-deas of I-deas software flat roof based on the intersection theory between two Non Uniform Rational B-Spline surfaces and 3-dimensional geometric modeling technique. The outline curve of the blend sheet-beam was approximated applied the line approximation form of Non Uniform Rational B-Spline, and the NC machining module of the bend sheet-beam was developed according to the NC machining facility preferences. The NC machining of the blend sheet-beam was realized on the different facility.