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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。
In order to make the train head structure fit the streamlined shape completely, a planar curved beam is proposed along the longitudinal, transverse and horizontal planes of the train to form a design method of spatial grid-like structure. The main edge of the planar curved beam is obtained by the method of discrete NURBS surface segmentation and iteration. The three-dimensional solid curved beam is generated by the three-dimensional solid geometric modeling technology based on the main edge. Beam three-dimensional entity map data surface, the use of coordinate transformation, create CAD plan. Based on the intersection theory of NURBS surface and the three-dimensional solid geometry modeling technology, a streamline train head structure design module was developed on ARX, I-deas Open I-deas development platform of AutoCAD. By using NURBS curve segment fitting theory fitting According to the parameters of CNC machining equipment, the numerical simulation processing module of streamlined train head curved surface curved beam was developed on AutoCAD ARX development platform. The numerical control machining of curved curved beam was realized on different CNC machining equipment.